whpennpnory tes sender tatccherene <ooeon oan ahs
AT
Y OF anny PAIGN
a eee ee ro Meee V43-Y99
ILLINOIS NATURAL AREAS INVENTORY
TECHNICAL REPORT
o ee
UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN
TECHNICAL REPORT
ILLINOIS NATURAL AREAS INVENTORY
performed under contract to the
ILLINOIS DEPARTMENT OF CONSERVATION
by the
DEPARTMENT OF LANDSCAPE ARCHITECTURE UNIVERSITY OF ILLINOIS - URBANA-CHAMPAIGN
and the
NATURAL LAND INSTITUTE ROCKFORD, ILLINOIS
This study was conducted for the State of Illinois pursuant to Contract #50-75-226 of the Illinois De- partment of Conservation. The study was financed in part through a planning grant from the Heritage Conservation and Recreation Service, U.S. Depart- ment of the Interior, under provisions of the Land and Water Conservation Fund Act of 1965 (PL 88-578).
Illinois Department of Conservation personnel re- sponsible for preparing the Request for Proposals and coordinating the work included John Schweg- man, contract liaison officer, and Dr. Edward Hoff- man, Dr. Robert Lee, Marlin Bowles, and Robert Schanzle.
Published November 1978
Illinois Natural Areas Inventory, Urbana
For additional Information
Natural Areas Section
Illinois Department of Conservation 605 Stratton Building
Springfield, Illinois 62706
Hwa
The Illinois Natural Areas Inventory was a 3-year project to find and describe natural areas for the Illinois Department of Conservation. The results of the inventory will be used to develop and implement a state natural area plan, to protect the diversity of natural features in Illinois.
Methods for finding natural areas consisted of compiling available information, examin- ing maps and aerial photos, aerial surveys, and on-site inspections. As many as 90 items of information were compiled for the significant sites. A computer-based system was de- veloped to store, retrieve, and analyze the information.
The 1,089 sites identified as natural areas have a total of 1,730 significant features. Six hundred and ten natural areas were identified because of their high quality, relatively undisturbed communities of plants and animals. There are 269 areas with endangered Species, 160 outstanding geologic areas, and 17 outstanding aquatic areas. Two hundred and fifty-one areas are nature preserves or school natural areas.
The approximate acreages of high quality, relatively undisturbed areas of land and water identified by the Inventory are as follows: 13,500 acres of forests, 2,300 acres of prairies, 1,300 acres of savannas, 6,000 acres of wetlands, 2,000 acres of lakes and ponds, and 600 acres of rocky glades and similar communities. These relatively undisturbed areas include seven-hundredths of 1% of Illinois’ total land and water area.
The natural areas represent a wide diversity of natural features. Most geologic forma- tions, major soil associations, and topographic features occur in at least one site listed by the project. Natural areas were found in all but three counties, but they are concen- trated in hilly regions, along rivers, and near cities.
About one-third of the natural areas are receiving some degree of protection, but only one-fifth of the significant natural features can be considered permanently protected. Half of the areas are threatened with destruction from changes in the use of the land.
Principal Investigator ROBERT B. RILEY
Director: Surveys JOHN WHITE
Director: Information System
CALVIN C. CORBIN (1977-78)
BRUCE HANNA (1975-77)
Director: Administration JOHN NELSON (1975-77)
Survey Personnel
Natural Area Ecologists JOHN A. BACONE FRANCIS M. HARTY MAX D. HUTCHISON DONALD R. KURZ
Senior Assistants MARILOU HINRICHS KATHRYN KERR
Field Assistants
DONALD COONS MARGARET M. FOSTER MICHAEL A. HOMOYA JULIAN J. LEWIS ROBBIN C. MORAN
Technical Assistants JEFFREY ACKER THOMAS BROWN STEPHEN ENGLAND DONNA EVANS
Information System Personnel JANET FININ MICHAEL GRADY
Administrative Personnel
JO POWELL
Natural Land Institute GEORGE B. FELL GLADYS CAMPBELL MAX D. HUTCHISON
Consultants
RANDY W. NYBOER GERALD PAULSON DOUGLAS C. WALLACE L. KEITH WILSON
MICHAEL H. MADANY
WARREN NETHERTON THOMAS POST WILLIAM P. PUSATERI JOHN T. REEVES ERICA L. ROWE
KATHLEEN FINNEY CAROL QUALKINBUSH DAVID STUDTMAN
JERRY SCHLESINGER RIKKI WELSH
CANDY WILLUT
GERALD PAULSON DR. CHARLES J. SHEVIAK RICHARD H. THOM
DR. FAKHRI A. BAZZAZ, University of Illinois: Urbana-Champaign DR. JOHN E. EBINGER, Eastern Illinois University
DR. LAWRENCE M. PAGE, Illinois Natural History Survey
DR. PHILIP W. SMITH, Illinois Natural History Survey
DR. H. B. WILLMAN, Illinois State Geological Survey
ILLINOIS NATURAL AREAS INVENTORY TECHNICAL REPORT
VOLUME I SURVEY METHODS AND RESULTS
John White
Illinois Natural Areas Inventory Urbana
November 1978
& JOe YA } LAR © tA Ped Aen
aid e ‘Tw esr AND Was a a 2 iBT nes st ideeeks. CAAtr Ca ed we Pr a Rie! Lew wx cee saee 6. 412 ~~ ls) Mh be vt Sa —~0he |) |
re me fate? i, SA7ZAl
ee peer 0, TRIPLE, Dee 0 Bee inner 08.(401 Se & PACE: Tee Neate) Wigan Gipeey Pah OD. iF > VOT’ D. pee Seeenal Wiet=+ eoee® 8 6 © Ut te fee Da [ereegpee Ore
WARLEN NFRD THOM. PL WULIANW YY, PEDATIRS (is v. WEB VRe rans. soe
LATHMLIIN vex “@ROl. OVAL AIMACSS OAVIG SIU MAM
Ray & DATAISNCILS VIKAS WEL ON
CARY
vrohravnl ease imumVv ond i 2ATD PAL saad t
DOR UMARLES | SNEVIAR
veme"Seof Ysdmatovt
ideouson @f Uberds 1°) Viege4 Teeeegenigp
CONTENTS
Part I. INTRODUCTION
1. Summary .
2. Introduction Purpose of the Illinois ‘Natural Areas Inventory Scope of this Report . 5 : Importance of Preserving Natural Areas : : Need for a Comprehensive Natural Areas inventory :
3. Basic Organization of the Inventory . Inventory Requirements and Guidelines
Definition of a natural area Sources of information Some basic guidelines .
Structure of the sa aad -
SURVEY Ss. - Offices and Saber Schedule
Basic Principles . : Information Requirements .
Basic information .
Location F
Natural oe ae F
Legal status and use , Discussion of preservation railues ‘ Supplemental materials
Part II. CONCEPTS AND TERMS
Natural Area Categories .
Introduction . c
Summary of Categories : : Category I: High quality terrestridi or “wetland
natural communities . Category II: Habitats with endangered species Category III: Habitats with relict species . Category IV: Outstanding geologic features . Category V: Nature preserves or lands that are
managed and used for natural science studies Category VI: Unique natural features . . Category VII: Outstanding aquatic features .
Natural Area Boundaries, Land Condition Classes, and Features p ‘ Introduction and Summary “
iii
5. Natural Area Boundaries, Land Condition Classes, and Features, continued
Land Condition Classes . Natural land Butter Vand... E Applicability of the land condition
classification
Boundaries
Features . aes Significant features. apa Exceptional features Notable features ; Artificial disturbance features Natural disturbance features
6. Natural Community Classification Geo eno ue SUMMARY | 2./hgee ty) 160 ict eich eae sl since eR
7. Natural Quality . Summary
Part III. METHODS
8. Compiling Available Information .
Purpose
RPEOCedune sn -al. : Gathering backeracndl faerie : Contacting people and agencies General publicity . Literature review .
Results
9. Examining Maps and Aerial Photographs Introduction ase enka te Map Resources Topographic ies Highway maps
Presett lement Vegetation “Atlas Re ieee
Soil maps . Geologic maps .
Aerial Photographs and Hi gh- aie itude Images ASCS aerial photographs . PHT pes Other aerial photographs Landsat images :
Procedure and Results
10. Aerial Survey . Purpose 6 Procedure and Results. General techniques Examples of techniques Effectiveness
iv
11. Initial Ground Survey Purpose . Procedure . Results .
12: Final Field Survey . Main Data Form . - Maps and Aerial Photographs - Vegetation Sampling . - Species Lists .
13. Information Collected about the Natural Areas Main Data Form ; Natural Area Files and Maps :
Part IV. SURVEYS
14. Category I Survey: Main Survey Summary . Oe LAER Ie
15. Category I Survey: Railroad Prairies
Summary .
Introduction
Procedure . é Preparation on ae Pei Se - Aerial survey : Initial ground survey Final field survey .
Results . Natural areas Disturbances .
16. Category I Survey: Cemetery Prairies and Savannas .
Summary .
Introduction
Procedure . = Office preparation : Pilot survey . Volunteer survey . Staff survey .
Results . 3 Natural areas Notable areas
17. Category II Survey: Habitats with Rare, Threatened, and
Endangered Species . Definitions and Procedures Introduction . : People and organizations involved’ with endangered species . Determining the status of species
Significant features and exceptional features
17. Category II Survey: Habitats with Rare, Threatened, and Endangered Species, continued Inventory procedures for animals Inventory procedures for plants Results . Number of significant: features ood excéptional features . Habitats and qiseedone toon Newly discovered species . 18. Category III Survey: Habitats with Relict Species . Definition yk recuted eve tusds Betocl fee Procedure . Results .
19. Category IV Survey: Geologic Areas Definition and Procedure Results .
20. Category V Survey: Natural Study Areas Definition : Se oe ork or pretae Procedure and Restiee
21. Category VI Survey: Unique Natural Areas Definition and Procedure Results
22. Category VII Survey: Aquatic Areas Definition and Procedure Results .
23. Literature Survey
Pen OSE 6 o 6 a
Procedure . :
Natural Area Bibliography : Summary : References to easllone References to biology and ecology SOWNKESS Ore jowiollseewewomS 5 o oo a 5 0 6 DRKEGS: Ose jawloiliceuenoiS 6 sg 5 5 656
Part V. RESULTS AND CONCLUSIONS
24. Effectiveness of the Methods .
Introduction
Finding Significant Features. Comparison of methods Adequacy of available information
Screening Potential Natural Areas . Source: Available information . Source: Maps and aerial photos Source; ~Acmialissurviey aise sald sie Source: Ground survey .
vi
24. Effectiveness of the Methods, conttnued
iiper cance OLREXPeVLONCe: (see eriicw eh am sk we fog. =n. +». «, « 04 Monplereness Of the) INVENtOLY as vem pees “aesmie@ = © 2 6 « 0105 ere On vere STIGNCY ee ete cco vets ss Ss» suse sm 6 = = ae LOS Catcoony: Mule SUTVCV esate omen. eos oop 6 poipete sues @, 0, 08 LOT Catreconv ant te SUV CVs cee Ciba cama hslehh «sc, +i a sg LOS CaCCEORY UV. SUEVCYS ns mck any fatars mama pieiabt se ese se UL GALeCOMy VESUTVEY ths RiSTAMS AS wae e CH te. oy soy ene mks Carean Va MIRISITEN CYR se ace n s Pamec Boer Teenage os 2 «ol LOS CAEGQODVEVEL SUEVCY, sa aecig« Ponte saenemd © «ca 2; 1s) LOS SUMTER ees 5, we ss DB ae Kins sgl geicaisinsmisly oa RUS 25. Summary of Natural Area Characteristics OT SD ep ty oa Number and Distribution of Natural eae ede Sipniticant,heatures, .. .-. shy aed const em slel Number and distribution by county aoe Pl Sos aero lula Number and distribution by Natural Division. and Section =. <u. ae Pee «GL A broad but uneven ease oe ea areas | aera: Oe, seas Distribution in “relation to “human population aoe er is: Nace laiGhanractbertstlCs i...) 0. 6 s) cee see ete een cna LO. ACTCACCHE TS SASS: ie Die gped- oo eee, ee otter fe VLG DEViCPS aC Ve ca se isc cig oh Ieuren to Sea's) cacteragici, SWuem ace Cane eee Topography .... ee ar eee er me Geologic formations De et ee es ea eke sf BavUirasS@CHAE IONS | 6.4 «. saiem.s. ose) sc aual aoe vee eee ee Watural commmities 205 5 os ys sJegic’ & Fo: See Cee Plane epmnMnidGies Vem eait. =e, onid«4 ieee ett baeereeee “alee FPOreSt COVED tVpes ...,+,».< -negstent Sneattinele = « 225 NatieeWUslTtyACAee: . Gee keh. GE. te we wn og 28 Pxeceprrouel™ reatutes**..s 12 hee, 207720, OO Sei aeeaS, 26420 Ownership, Use, Management, and Protection ....... . 120 Type-Of OWREESNADny hevcanabnd kok -benstuetAt sores «8°° WOMBLE ONNELSHLES ice ew Se ean me es ee a es ee on ee Usessotunacitalvareas 82" .* 5". ft. ss ee eee a eke mee Use of surrounding land cases.) slsgeysonet wot - 22 ManaicemenbeneedS: 4... sw yous © os <4 ce wool ae MN is te emt Management “agencies . 9. 2.0. es ee ee we ew he Preservation status: ...:...s.+,» apeltesetesieeless « , 124 TUG GeLSee th Ok Ee Uren. sie GES vaste ee a, wo LONER NE easy Ae ee Lee 26. Destruction and Preservation of Natural Areas ......... 125 Past Destruction of Natural Land and Water ....... . 125 Plant, Commonitti6S:<. s.d sub. vce. 3, s,s emer ee «ae Fata «.. eshte wits: Cafial ac 28 sie ink inh cen) Sg yas SUE Aquatic ecosystems youre TD SRA ade ee ee Present Destruction of Natural “Areas: <. wehmells tanta anes. ae) Wie urn AfegS Pelee. oy aa ke 6 yo, See Fe we AD PAST ANSE AOE Gots eo, Me oto Sak Ree ee ee ee ee Hosts: leaked: See 5 betas ant tah esde x _abievsawe «LeU PRAITLCS: 3 «x OS OT ORE EES ey Feu eI st Savannas and barrens tives ee ee Ree be mee
vii
26. Destruction and Preservation of Natural Areas, continued
Wetlands:andpondsit> . Fess * tae ees ne he eee Primary ycommuniities: iP: Ga iarere: As geste ee ee ree bee Canvies: (<9. ar ae. ES eee so Be Pee ae ig eng can er Habitats with endangeredtplants*™. Vo sus o «5 eeeueee Habitats with endanpered=anamailsie.) se sem. ene Habitarsmwatthe melkict espe Giles scm) wer arene scatllsns islet imemmrrnea Geollociic vareas 294% Pie sl eget gt School natural areas and nature preserves 2 © ue 9s eee Unique-natural areas: ; KAS Ass by. Wace. co. fl tel eee lakes: andi streams 4.80. % ss). st atte nc) weer en cs one Future “trends « -. “s«)345. pom e-cm ae Get hot atin Sake ac) oe ae ee 27. Future Needs. a: BL ts . sa ne Adequacy of the Present System cE Preserved INACEIS Gg oe Sharir teat tie ple or etait eG cae Las Updating the Inventory. us Re ee ee ae ce) oe ee eee Moni toraingenatunaltareasiey.s.) csr tee ee erie si emer eraE Updating the information... enh lB 5 Caner ey P= 12:2 Preserving All of Our Natural Heritage. Snr ce mie oily Suto sige Save amerepm ene
Part VI. REFERENCES CITED
Part VII. APPENDICES
1. Number and Distribution of Natural Areas and
Significant Featares®.:.5.). 4. ¢)SPase Age Sea nee ee
2. Summaries of Natural Quality, Natural Communities, and Naturals Divisions;andsSections, 2. .5- sats. cat «ets see 3. Rare, Threatened, and Endangered Species ............ 178 4. Phystographicrinaes’ tc &inloes cacenuRhodin 5. Sa eceeee oer eee 5.° Major Topographic Features,“ S)" BasOOTtie OO Gags. eee 6. Individual Topographic Features <i 5.<.-ssnceeneee © 9S) eee #.* Geologic Formations «.-..i+.+ 245 sb enee ch emesUee eee G5 a unos 8: “Soil Associations: <6 sg" 5 enya eee eee en ee 9. “Forest Cover TypeSio gc ke Te bem e othe nae anes. Sens en ee ee 10.- Stream: Systemsen) fi act Feattren tn FO4PAIVENOS SORES 5 ogee ee di. Uses of Natural: Areas” Seo 00 cs cgi c kn meee tienes ee ee eee 12. Management Needs st. 2°20, d2g07ee Be. GET, 2eeteet.. 2 eee 13. Management Agencies “S . 4 «¢..sc vue «tem Bee On 14. Ownership, Preservation Status, and Threats .......... 224 15. ‘Why Natural AreascExist ©... tet. vecsmseeaseeaLReee eee an eee
Vili
16.
LT. 18. Ao. 20. Za 22s 23. 24.
aa
26. Zi. 28. 29. 30. Sis 52).
Ga
Determining Boundaries of Natural Areas, Significant Features, and Land Condition Classes .
Main Data Form and Instructions
Examples of Natural Area Data
Presettlement Vegetation Atlas of Illinois .
Some Procedures for Identifying Natural Communities Some Procedures for Detecting Disturbances . Grading Natural Quality
Some Procedures for Finding Railroad Prairies
Selecting Cemeteries to be Surveyed for Prairie and Savanna Remnants .
Criteria for Designating a Species as Rare, Threatened,
or Endangered Field Survey for Endangered Plants . Determining Preservation Priorities Plant Communities Species Lists Classification of Natural Communities in Illinois Monitoring Natural Areas .
Scientific Names of Plants and Animals Mentioned by Common Name in the Text
List of Major Memoranda, Reports, Instructions, and Forms 5
ix
. 236 S a4 255
262 263 267 280 286
. 290
- 292
296
. 298 - o04 . 306 5 O09 . 406
. 408
. 414
TABLES
Natural area categories and significant features .
Comparison of significant features, exceptional features, and notable features .
Degree with which natural features are represented in preserved areas
Number of natural areas and significant features (by category) in each county .
Number of natural areas and significant features (by category) in each Natural Division and Section .
Summary of natural quality, natural communities, and Natural’ Ditva'svons and Sectionsiy a. iea\-ne anu
Acreage of Grade A §& B land and water identified by the Inventory in each Natural Division and Section... .
Acreage of Grade A §& B land and water, by community class, identified by the Inventory in each county
Rare, threatened, and endangered fishes
Rare, threatened, and endangered amphibians and reptiles .
Rare, threatened, and endangered birds
Rare, threatened, and endangered mammals .
Rare, threatened, and endangered vascular plants . Physiographic units
Major topographic features
Individual topographic features
Geologic formations
Soil associations
Society of American Foresters' forest cover types Stream systems .
Uses of natural areas
Summary of major management needs
Management agencies
Ownership type, according to natural area category .
Ownership type for Category I natural areas, according to
community class
Preservation status, according to natural area category
pil
26
140
164
166
170
7S
176 180 181 182 184 185 198 201 204 209 213 216 217 218 221 223 225
225 226
Ze
28. Zo.
30. yi lie ae 35. 34. <Seie 36. Si. 38.
Preservation status of Category I natural areas, according to community class .
Threat of destruction, according to natural area category
Threat of destruction of Category I natural areas, according to community class .
Threat of destruction, according to ownership type . Threat of destruction, compared with preservation status . Threats to significant features of natural areas
Why natural forests exist
Why natural prairies exist .
Why natural savannas and barrens exist .
Why natural wetlands exist .
Why habitats with endangered plants exist
Natural community classification .
Xi
. 226 ee)
yn227
228 228
, 229 Zou
232
. 250 - 234 AES - 3518
or Ga Ne
uw
FIGURES
Number of references to natural areas published in each decade .
Number of significant features (by category) in each county . : se oe eee. Sy ae A Meet Be
Distribution of natural areas according to 15-minute topographic quadrangles
Relative acreage of land and water that was identified by the Inventory as undisturbed or nearly undisturbed in each county
Main Data Form .
Example of a computer printout and topographic map for a Natural area . RIC OMe oi! ct ac. cnet
Example of a computer printout from a statistical program
Natural Divisions of Illinois PLATES
County map of Illinois . The Middle Fork of the Vermilion River . A canyon in Starved Rock State Park
A section of the Presettlement Vegetation Atlas of Illinois
An example of an aerial photo used to select potential natural areas
A bald cypress along the Cache River . A red squirrel along the Kankakee River Prairie plants surrounding a gravestone A cave in the Shawnee Hills
A calcareous seep community in the Morainal Section of the Northeastern Morainal Division .
mera!
95
112
114
121
244
256 261 512
SCL
146 162
309
ACKNOWLEDGEMENTS
We are especially grateful to the hundreds of landowners who granted
permission to visit their properties.
The Inventory's natural area ecologists were responsible for the majority of work on this project. The ecologists were as follows: L. Keith Wilson, Francis M. Harty, and Gerald Paulson (northern I1li- nois); John A. Bacone (central Illinois); Douglas C. Wallace (western I1li- nois); Randy W. Nyboer (southwestern Illinois); and Max D. Hutchison and Donald R. Kurz (southern Illinois). Each of these people was responsible
for all aspects of the survey work in a particular part of the state.
The following people were field assistants: Erica L. Rowe, John T. Reeves, William P. Pusateri, Thomas Post, Warren Netherton, Robbin C. Moran, Julian J. Lewis, Michael A. Homoya, Margaret M. Foster, and Donald
Coons.
Technical assistance in the main office was provided by David Studtman, Carol Qualkinbush, Kathleen Finney, Donna Evans, Jeffrey Acker,
Thomas Brown, and Stephen England.
Three assistants had major, independent responsibilities that were at the same level as natural area ecologists but were more specialized: Michael H. Madany (field surveys, classification), Kathryn Kerr (Category II, IV, and V areas; caves), and Marilou Hinrichs (preparation and com-
puterization of the natural area data).
Dr. Fakhri A. Bazzaz of the University of Illinois was always a will-
ing advisor and friendly critic of inventory methods.
The staff at the Natural Land Institute's main office in Rockford worked closely with the Inventory. George B. Fell provided advice and consultation throughout the project. Work was coordinated and shared with the Natural Land Institute's Endangered Species Project, directed by Richard H. Thom and Dr. Charles J. Sheviak. Jean Sheviak compiled sum- maries of collection records for the Inventory, and Mark Ritke worked with the Inventory on endangered species as a student intern from Eastern
Illinois University.
xiii
Clerical and secretarial work was provided by Marilou Hinrichs, Candy Willut, Jo Powell, Celeste Conner, Ada Siler, Darlene Graves, and Gladys
Campbell. Joyce Hipskind typed the final draft of this report.
Marilou Hinrichs prepared the photographic prints, and John Richard- son supplied photographic assistance. Plate 1 is from the University of Illinois Cooperative Extension Service. Plates 2, 3, 7, and 8 are by Marilou Hinrichs. Plate 4 is redrawn from the unpublished Presettlement Vegetation Atlas of Illinots, by John White. Plate 5 is from the U. S. Department of Agriculture, Agricultural Stabilization and Conservation Service. Plates 6 and 9 are by John White, and Plate 10 is by Marlin
Bowles. Donna Evans and Jo Powell prepared the figures.
John E. Schwegman of the Department of Conservation's Natural Areas Section served as project coordinator and contract liaison officer. Robert Schanzle and Marlin Bowles, also of the Natural Areas Section, helped define the Department of Conservation's information needs in rela-
tion to the natural area survey.
Many people outside the Inventory staff contributed to the project. These people gave freely of their time, skills, and knowledge as a con- tribution toward natural area preservation, without reimbursement and often at additional personal expense. The project benefited greatly from the ambitious efforts and diversity of interests of these volunteers.
The contributions of several people deserve special mention.
Dr. H. B. Willman of the Illinois State Geological Survey, in his typical style, provided an excellent compilation of geologic areas. Dr. Willman developed the classification systems for topographic features
that were used by the Inventory.
Dr. John E. Ebinger of Eastern Illinois University contributed hun- dreds of hours of enthusiastic fieldwork and herbarium work to the Inven-
tory.
Dr. Robert H. Mohlenbrock of Southern Illinois University generously shared his encyclopedic knowledge of vascular plants in Illinois, allowed
us to use a prepublication draft of Distributton of Illinois Vascular
Xiv
Plants, and loaned his unpublished notebooks of information about natural
areas in southern Illinois.
Dr. Robert A. Evers of the Illinois Natural History Survey graciously made available the information he had compiled during a career of studying
Illinois' natural areas and flora.
Dr. Philip W. Smith and Dr. Lawrence M. Page of the Illinois Natural History Survey shared the Survey's information about endangered animals and compiled a list of outstanding aquatic areas. Michael A. Morris of the Natural History Survey, working through the Endangered Species Pro- ject, compiled distribution records of endangered animals for the Inven-
tory.
Dr. Robert F. Betz inspired and encouraged the survey of cemeteries by sharing his knowledge gained by evaluating over 800 cemeteries for prairie remnants in northern Illinois. Dr. Betz has pioneered in the
study, restoration, and preservation of cemetery prairies.
Dr. Jean W. Graber and Dr. Richard R. Graber of the Illinois Natural History Survey provided a wealth of information and many hours of discus-
Sions about endangered birds.
Personnel at the Department of Conservation's deer hunter check sta- tions, coordinated by Forrest Loomis, distributed a questionnaire about
endangered animals to deer hunters.
Dr. Brooks M. Burr and students at Southern Illinois University con-
ducted surveys of fishes in certain lakes and streams for the Inventory.
Robert Walker and Donald Greene generously shared the results of an unpublished survey of outdoor classrooms by the Conservation Committee of
the Illinois Chapter of the Soil Conservation Society of America.
Don Roderick of the Illinois Office of Education assisted in mailing a questionnaire about use of natural areas to the elementary and second-
ary schools in Illinois.
Seventy people took responsibility for surveying cemeteries for prairie and savanna remnants. Other people who joined these 70 volun-
teers to survey certain counties remained anonymous to the Inventory.
XV
Perhaps it is best not to attempt an incomplete listing of participants, but one person deserves special mention: Dr. Paul Shildneck surveyed
cemeteries in all or part of 14 counties.
The Inventory benefited from a series of workshops on endangered species, conducted by the Endangered Species Project. In addition to staff from the Inventory and the Endangered Species Project, the follow- ing people participated in the workshop on fishes: Dr. William Southern (Endangered Species Protection Board), Dr. Philip W. Smith (Illinois Nat- ural History Survey), Dr. Lawrence M. Page (Illinois Natural History Survey), Michael A. Morris (Illinois Natural History Survey), Dr. Larry John (Western Illinois University), Dr. Leonard Durham (Eastern Illinois University), Larry Dunham (Department of Conservation), and Dr. Brooks M.
Burr (Southern Illinois University).
The following attended the workshop on amphibians and reptiles: Harlan Walley (Northern Illinois University), Dr. Gordon Thurow (Western Illinois University), Dr. Philip W. Smith (Illinois Natural History Sur- vey), John E. Schwegman (Department of Conservation), Alan Resetan (Field Museum of Natural History), John Murphy (Chicago Herpetological Society), Michael A. Morris (Illinois Natural History Survey), Dr. Edward 0. Moll (Eastern Illinois University), Richard Funk (Illinois State University), Dr..Lauren E. Brown (Illinois State University), Dr. Ronald A. Brandon (Southern Illinois University), and Dr. Ralph W. Axtell (Southern I11li-
nois University).
The mammals workshop was attended by: Harlan Walley (Northern Illinois University), Dr. Howard Stains (Southern Illinois University), Dr. Glen C. Sanderson (Illinois Natural History Survey), Dr. Donald F. Hoffmeister (University of Illinois), Dr. William G. George (Southern Illinois University), Dr. Dale E. Birkenholz (Illinois State University),
and Dr. Richard D. Andrews (Eastern Illinois University).
Participants in the workshop on endangered birds were: Dr. William E. Southern (Endangered Species Protection Board), Vernon Kleen (Depart- ment of Conservation), Dr. S. Charles Kendeigh (University of Illinois), Lee G. Johnson (Natural Land Institute), Dr. L. Barrie Hunt (Eastern
Illinois University), Dr. Richard R. Graber (Illinois Natural History
XVi
Survey), Dr. Jean W. Graber (Illinois Natural History Survey), Donald M. Elsing (U. S. Forest Service), Marlin Bowles (Department of Conservation), H. David Bohlen (Illinois State Museum), Dr. Richard G. Bjorklund (Bradley University), and Dr. Dale E. Birkenholz (Illinois State University).
The workshop on endangered plants included: Gerould S. Wilhelm (The Morton Arboretum), Dr. Julius Swayne (Rend Lake Community College), Dr. Paul Shildneck, John E. Schwegman (Department of Conservation), Raymond Schulenberg (The Morton Arboretum), Dr. Kenneth R. Robertson (Illinois Natural History Survey), Jerry Nilsson (U. S. Forest Service), Dr. Lorin Nevling (Field Museum of Natural History), Dr. Robert H. Mohlenbrock (Southern Illinois University), Roger McMannis (U. S. Fish and Wild- life Service), Walter Matia (The Nature Conservancy), Dr. Alfred C. Koelling (Illinois State Museum), Dr. Almut Jones (University of I1li- nois), Dr. Robert D. Henry (Western Illinois University), Dr. John E. Ebinger (Eastern Illinois University), and Carter D. Christenson (Soil
Conservation Service).
Participants in these workshops provided information to the Inven- tory not only at the workshops, but by sharing their personal knowledge and making available personal and institutional records and collections
at other times.
In addition to the people who participated in the endangered species workshops, the following people assisted the Inventory by providing in- formation about natural areas or by making facilities available to the project: Dr. John Warnock (Western Illinois University), Douglas Wade (Northern Illinois University), Floyd Swink (The Morton Arboretum), Doris Sublette (Illinois Natural History Survey Library), Dr. Paul D. Sorenson (Northern Illinois University), Dr. Peter Schramm (Knox College), Jean Ray (Morris Library, Southern Illinois University), Donald Pretzsch (Soil Conservation Service), Dr. W. D. Klimstra (Cooperative Wildlife Research Laboratory, Southern Illinois University), G. Tim Keller, Corliss I. Ingels, Dr. Stanley E. Harris, Jr. (Southern Illinois University), Dr. James Hardin (Cooperative Wildlife Research Laboratory, Southern Illinois University), Philip Hanson (Field Museum of Natural History), Neil Gaston
(Illinois Chapter, The Nature Conservancy), Thomas Walkington (Illinois
xvii
Chapter, The Nature Conservancy), Howard Fox (University of Illinois), Henry Eilers, Dr. Ben L. Dolbeare (Sangamon State University), Margaret
Irene Cull, and David Cobb (University of Illinois Library).
Many other people and agencies assisted the project. Conservation districts and forest preserve districts provided information about areas in their jurisdictions. The Agricultural Stabilization and Conservation Service (ASCS) of the U. S. Department of Agriculture provided work space for the Inventory staff to examine aerial photos in each county ASCS of- fice, loaned aerial photos, and provided information about potential natural areas. District Conservationists of the U. S. Department of Agriculture's Soil Conservation Service and District Foresters of the Illinois Department of Conservation provided information about many nat- ural areas. A skillful and enthusiastic group of pilots from flight services throughout Illinois contributed to the efficiency of the field- work. The Illinois Speleological Survey made its files on 300 caves
available to the Inventory.
This report should perhaps have at least a dozen authors, including each of the natural area ecologists. The staff members formed a dedi- cated and unselfish group, willing to work under continual deadlines and unwilling to produce less than their best possible efforts. They worked far longer than an 8-hour day on countless occasions and many continued to work for the project after they had left the payroll. The privilege of writing the final report fell to the survey director, but the field- workers continued to help. In a few instances, it was possible to share authorship of sections of this report with another staff member who wrote a part of the text. Ten former staff members reviewed the report and suggested many improvements. Francis M. Harty was especially adept and
diligent in constructive criticism of the report.
John White November 1978
Xviil
eel STEPHENSON | WINNEBAGO] 3 MC HENRY vee ° ° Ls] CARROLL OGLE DE KALB
WHITESIDE LEE
ROCK ISLAND
IROQUOIS
VERMILION CHAMPAIGN
DOUGLAS EDGAR MACOUPIN
EFFINGHAM JASPER Yvon] = ae
CLAY RICHLAND WAYNE JEFFERSON
HAMILTON RANDOLPH PERRY FRANKLIN co ald
uns
EDWARDS
Plate 1. County map of Illinois.
xix
PART I INTRODUCTION
The basic goals and accomplishments of the Inventory are pre- sented in Part I. The values of natural areas are described,
and the importance of an inventory is explained.
This outstanding aquat-
Plate 2. The Middle Fork of the Vermilion River. te area ts the only knowm habitat for the bluebreast darter tn Itltnots.
Four other natural areas were tdentified along this central Illinois
stream.
Section l.
SUMMARY
An inventory of natural areas in Illinois was completed in 1978 by the University of Illinois and the Natural Land Institute under a con- tract with the Illinois Department of Conservation. The 3-year project consisted of surveys to find, evaluate, describe, and classify natural areas of statewide significance. A computer-based information system was developed to store, retrieve, and analyze the natural area data. The re- sults of the inventory will be used to develop and implement a plan to
protect the natural features in Illinois.
The inventory was a search for the following kinds of significant
features:
(1) Relatively undisturbed terrestrial or wetland natural communities (2) Habitats with endangered or threatened animals or plants
(3) Habitats with relict species
(4) Outstanding geologic features
(5) Nature preserves or areas used for natural science studies
(6) Areas with unique natural features
(7) Outstanding aquatic areas
The following classification systems were developed to aid in col- lecting and analyzing the information: (1) Categories and lists of significant features, which are the features that allow a site to qualify as a natural area (2) A classification of natural communities of plants and animals
(3) A system of grades for describing the effects of disturbance to an area
(4) A classification of topographic features (5) Other terms for describing and mapping an area's natural and cultur- al features The various kinds of natural areas were inventoried with separate surveys, based on different sources of information. Sites with relative-
ly undisturbed terrestrial or wetland communities were found mainly
with original searches. Sites with relict species were also found by field surveys. Habitats with endangered species were inventoried by re- lying mainly on available information, supplemented with fieldwork. The Illinois State Geological Survey compiled a list of outstanding geologic areas. The Illinois Natural History Survey recommended outstanding natu- ral lakes and streams. Nature preserves and school natural areas were
found through publications and mailed questionnaires.
The surveys were processes of selecting potential natural areas, ex- amining them, and rejecting the sites that did not qualify. Each stage of the survey relied on the previous stage and examined the remaining areas in more detail. The stages were as follows:
Compiling available information
Gathering background material
Contacting people and agencies Reviewing literature
Examining maps and aerial photographs Aerial survey Initial ground survey
Final field survey
Inventories of geologic areas, aquatic areas, and school natural areas
were conducted almost solely by compiling available information.
Many people and agencies contributed information about areas, espe- cially habitats with endangered species. The Natural Land Institute's Endangered Species Project shared the responsibility for compiling rec- ords of endangered species from people, organizations, publications, museums, and herbaria. Specialists provided information about the cur- rent distribution and population status of endangered species in a series
of workshops.
A literature review revealed over 1,400 references to areas identi- fied by the Inventory and about 1,700 other publications about the ecolo-
gy or field biology of Illinois.
The survey of relatively undisturbed natural communities relied largely on maps and aerial photos to eliminate disturbed areas and to
select possible natural areas. All potential sites were surveyed in the
field. Approximately 5,000 potential natural areas were considered in this part of the inventory. Surveying from an airplane proved effective
and efficient for screening the sites.
Special surveys were conducted to find prairie and savanna remnants on railroad rights-of-way and in cemeteries. All 11,000 miles of rail- road in Illinois with potential for prairie remnants were surveyed, as
were 3,923 cemeteries in the prairie regions of the state.
As many as 90 items of information were compiled for the natural areas. These included (1) basic information such as the area's name, boundaries, significant features, location, and acreage, (2) descriptions of natural characteristics such as natural communities, plant communities, degree of disturbance, geology, topography, and soils, (3) information about the area's use such as ownership, management, preservation status, and threats of destruction, (4) a discussion of preservation values, and (5) supplemental materials such as species lists, vegetation sampling
data, and literature citations.
A total of 1,089 natural areas were listed. Some natural areas have more than one significant feature. The number of significant feature oc-
currences are as follows:
689 high quality terrestrial or wetland natural communities 521 habitats with endangered species
45 habitats with relict species
160 outstanding geologic features
266 nature preserves or school natural areas
30 unique natural features
17 outstanding lakes or streams
In addition, many other exceptional features were found. Exceptional features are not important enough to be the reason for identifying a nat- ural area, but they were listed when they occurred at a site identified for some other, significant feature. For example, 910 occurrences of hab-
itats with exceptional (rare or threatened) species were identified.
The acreages of high quality natural communities identified by the
Inventory are as follows:
FORGSES:.. cues Ga «. SPR aS Aire eho ee ee ee eo 4 Prairies «ices Gaels a igo PSameeOe- Cae Teme oR Oooe SAVANTIAS) «sei as: sy reBe> (25 Gee TeR ER ba ey oop eZ 96 Wetlands: < ee ia Hi ca li: bee ohare TR eo 64 eae O29 lhakestand sponds, wee aa beeen ts) tame one eI ST OG Glades and? simular icomunvttiesi es 2 9. 602
These relatively undisturbed areas include seven-hundredths of 1% of I1li-
nois' land and water.
The natural areas represent a wide variety of natural features. Most geologic formations, major soil associations, and topographic features in Illinois occur in at least one site listed by the Inventory. Natural areas were found in all but three counties, but they are concentrated in
hilly regions, along rivers, and near cities.
Slightly more than half of the natural areas are in private owner- ship, and are not protected by the owner; and half of the areas are threatened with destruction from changes in use of the land. About one- third of the natural areas are receiving informal or formal protection, but only one-fifth of the occurrences of significant natural features can
be considered permanently protected.
The project was as thorough as practical within limits of time and money and within the guidelines set by the Department of Conservation. The Inventory found that compiling available information must be supple- mented by original searches and fieldwork to assure accurate and uniform
information.
Section 2. INTRODUCTION
Purpose of the Illinois Natural Areas Inventory
The Illinois Natural Areas Inventory was a systematic effort to find, evaluate, describe, and classify natural areas for the Illinois Department of Conservation. The purpose was to provide accurate and detailed infor- mation about the location and characteristics of natural areas of state-
wide significance.
Scope of this Report
This report describes the methods and summarizes the results of the surveys. The Inventory's computer system is described in an accompanying report. The Illinois Department of Conservation and Illinois Nature Pre- serves Commission are using information compiled by the Inventory to de-
velop and implement a plan to preserve natural areas in the state.
Importance of Preserving Natural Areas
A detailed discussion of the value of natural areas is beyond the scope of this report, but others have treated the subject ably. A report entitled The Preservation of Natural Diversity: A Survey and Recommenda- tions by The Nature Conservancy (Humke, et al., 1975) reviews the need for preserving natural diversity and emphasizes the vital role of natural ecosystems in maintaining a healthy environment. Complex natural ecosys- tems are stable and can restore themselves when disrupted, provided that the diversity of natural organisms is maintained. However, disruption and destruction of natural areas is so widespread and continual that it
is now necessary to preserve and actively protect natural areas.
A discussion of the need for preserving natural areas is in the Guidelines for the Illinois Nature Preserves System (Fell, et al., 1972) These reasons are summarized in the Commission's Two-year Report (11li-
nois Nature Preserves Commission, 1973) as follows:
In this day of tremendous technological advancement there can be no question of the value of basic scientific research. Natural areas are resource materials from which new knowledge can be derived. As scientists learn more about the world of nature, they are increas- ingly aware of the tremendous loss that will be suffered with the impending annihilation of natural communities all over the world. The loss in real wealth from the extinction of living forms is be- yond comprehension. Natural areas can serve as check areas in stud- ies relating to air, water, and soil pollution. Gaining a greater knowledge of wild communities and populations can lead to a better understanding of the growing problems of human society, urban envi- ronment, and population control, and serve valuable functions in research in many aspects of land management.
Natural areas serve as outdoor classrooms for students of all levels, from grade school through college. They provide a teaching resource to fill the need of contact with the world of nature.
Plants and animals have evolved into a bewildering diversity of forms, varying in infinite detail with their adaptation to varying climates, soils, and living conditions. Researchers find that the wild relatives of domesticated species are valuable sources of new genetic material. The plants and animals man uses are only a tiny fraction of the wild things that inhabit the earth. The potential usefulness of the others is unknown but doubtless enormous. We are constantly discovering new uses and products from wild plants and animals previously unexploited.
Many forms of life will perish from the earth if we do not spare bits of their native habitats as havens from the flood of civiliza- tion. Simply to keep on earth the awe-inspiring myriad array of living things is our obligation to future generations. We should also recognize that these creatures have a right to a place on earth.
Natural areas are sources of beauty and inspiration, both as scenery and in the more intimate sense of the form and color of individual groups of living things.
Natural areas also serve as living museums--examples of the rich and diverse natural world from which the pioneers built this country. They are historic memorials that serve as living links with the primitive past in such a way as to enhance our understanding and perception of the world we live in.
Need for a Comprehensive Natural Areas Inventory
Many people and agencies own, manage, and use areas with outstanding
natural values. Private landowners hold and personally protect many nat-
ural areas, and interested citizens watch and manage nature preserves.
Federal agencies such as the Forest Service, Fish and Wildlife Service,
and Army Corps of Engineers manage lands with significant natural area
values. Local agencies, including forest preserve districts, conserva- tion districts, park districts, zoning boards, and planning commissions participate in the protection and use of natural areas. Schools at all levels own and use natural areas for teaching and research. Private preservation groups such as the Natural Land Institute and The Nature Conservancy are responsible for preserving many of Illinois' most out- standing natural areas. The State of Illinois is involved with natural areas through its various departments and commissions, especially the De- partment of Conservation and Nature Preserves Commission. Our natural heritage is assured increased protection when these concerned individuals and groups are aware of the location and significance of natural areas. More natural areas are destroyed through ignorance than are lost because
people are aware of them and abuse them.
The Department of Conservation protects natural areas by acquiring and managing certain areas, by analyzing proposals for publicly regulated development projects, and by distributing money to local governments for land acquisition. The Illinois Nature Preserves Commission and the De- partment are responsible for the Illinois Nature Preserves System, which provides for dedication and protection of nature preserves under State law. Accurate and detailed information about natural areas is needed to
fulfill these protection goals.
There might be some question about the need for a large-scale, de- tailed natural area survey, but the Department of Conservation foresaw the potential benefits. Now that it has been completed, the value of a
comprehensive effort is even more apparent.
One question is, "We already know of more natural areas than we can posstbly save, so why look for more?" The answer is that, given limited resources for preserving areas, one should be certain that time and money
are spent on the most important areas.
Another argument is, "We already know the most important areas--they are obvious without a detailed inventory." This did not prove to be the case in Illinois. Prior to the Natural Areas Inventory, information about natural areas had been compiled by the Nature Preserves Commission, Natu-
ral History Survey, and Department of Conservation. So little is left of
10
Illinois' original natural communities that it might appear that the sig- nificant natural areas would have been readily apparent and would already have been found, but 61% of the 610 sites with high quality natural com- munities that were identified by the Inventory were previously unknown to the Department of Conservation and the Nature Preserves Commission. These new areas include not only small, obscure areas but large forests, wet- lands, and other communities. In terms of acreage, these newly discovered areas include 42% of the high quality natural communities identified by
the Inventory.
"But how many of these new areas could have been found by just com- ptling the avatlable information and not dotng original research?" The Inventory compiled information available from people, agencies, and the literature, as well as doing its own surveys, so it is possible to show how many significant natural features would have been found if the pro- ject had stopped after compiling existing information. The project would have been able to identify with certainty 29% of the areas with high qual- ity natural communities. Information that would have required further checks to substantiate would have been available for 14% of the areas,
and 57% probably would have been overlooked.
In addition to finding as many significant areas as possible, the Inventory acquired accurate and uniform basic information about the sites. The staff visited all areas with relatively undisturbed terrestrial or wetland communities, and they checked sites for endangered species if current and adequate information was not available. If the project had relied solely on information from secondary sources, the amount of data that could have been collected in a uniform manner for all areas would have been very limited, and nonqualifying areas would have been included by mistake. The Inventory had a trained and coordinated staff of ecolo- gists to collect and evaluate information, rather than relying on other sources such as publications that might be out-of-date. An analysis of how much accuracy and completeness would have been sacrificed by omitting
fieldwork is presented in Section 24.
An inventory brings information together into one information sys-
tem, so that areas can be readily compared and evaluated. Requests for
It
information from planning agencies and for environmental impact analyses can be answered with less effort. The Department of Conservation reviews the potential impact of 10 or more proposals for development of water areas, highway corridors, and other sites in a typical week. Unneces- sary conflicts with developers are avoided by planning ahead. Less time is spent responding to emergencies, and the time that is saved can be
used to protect areas.
A comprehensive inventory provides information needed to determine which natural areas are most significant and needed to complete a nature preserves system. A plan based on a solid background of information is more likely to be accepted by the people of Illinois and by the owners and managers of natural areas. Time and money for a systematic invento- ry are well spent to assure that the right areas are given priority for preservation. It costs money to inventory a natural area, but it costs even more money to negotiate preservation or to acquire an area, and Management costs continue indefinitely. Dedicating an area to preserva- tion as its highest and best use is a big commitment to the future, and public agencies have an obligation to make correct decisions about which
areas should be preserved.
The Illinois Natural Areas Inventory will continue to be updated. However, as much information as possible was collected in an initial ef- fort instead of relying on gradual accumulation of information as it be- comes available. Otherwise, doubt would continue about the relative value of areas because significant sites might have been overlooked. In the meantime, natural areas would continue to be destroyed. Threats of destruction were identified for half of the natural areas, and certainly more are threatened with disturbances unknown to the Inventory. The im- pact of development on the remaining natural areas is described in Sec-
tion 26.
12
Section 3. BASIC ORGANIZATION OF THE INVENTORY
Inventory Requirements and Guidelines
Definttton of a natural area
A natural area was defined as a tract of land or water with a natu- ral configuration or sufficient buffer land to insure its potential for protection and proper management, that: (1) contains relatively undisturbed terrestrial or wetland natural com-
munities, which have fauna and flora that reflect as nearly as possible the conditions at the time of settlement,
(2) is a habitat with an endangered animal or plant, (3) is a habitat with relict species, (4) has an outstanding geologic feature,
(5) is used and managed as a nature preserve or as a natural area by a school,
(6) has a unique natural feature, or
(7) is an outstanding natural aquatic area.
The definition was refined and further defined in the natural area cate-
gories discussed in Section 4.
Sources of tnformatton
As specified by the Department of Conservation, various kinds of nat- ural areas were surveyed in different manners. Information about areas with relatively undisturbed natural communities and with relict species was gathered from field surveys. The inventory of endangered species relied mainly on existing records, but species were checked in the field when necessary and practical. Many sites with endangered species were discovered through other phases of fieldwork. The inventory of geologic areas was compiled by the Illinois State Geological Survey. The inven- tory of lakes and streams relied on recommendations from the Illinois Natural History Survey. The survey of school natural areas was conducted
by mailed questionnaires and review of publications.
13
Some baste guidelines
Acreage standards.--Minimum size standards were defined for areas with high quality natural communities. Such areas were included if they were 20 acres or larger, with the following exceptions: (1) If a parti- cular type of natural community is not normally as large as 20 acres (such as seeps and glades), then the 20-acre minimum did not apply. (2) Natural prairie remnants as small as one-quarter acre were inventoried. (3) An area smaller than 20 acres was recognized if it was the least dis- turbed remnant of a particular kind of community. Minimum acreages were not defined for sites other than the ones with high quality communities. Geologic areas, habitats with endangered or relict species, and school natural areas could be any size that adequately represented the signif-
icant feature and provided potential for protection of the area.
Degree of disturbance.--Outstanding representatives of natural com- munities were selected on the basis of relative lack of disturbance, but disturbed areas could qualify in the other natural area categories. Al- though the term natural area was applied to any site listed by the Inven-
tory, many are not undisturbed sites.
OQunershtp and preservation status.--All of Illinois was surveyed, and areas were inventoried without regard to the type of ownership or whether an area was preserved. Information was collected about all natu-
ral areas to provide a complete base of information.
Structure of the Inventory
The project consisted of two parts: (1) surveys to find and to col- lect information about natural areas, and (2) an information system to store, retrieve, and analyze the data. The information system consists of maps, files, and a computer system that is described in an accompany-
ing report.
Surveys Surveys of different categories were often conducted at the same
time. Fieldwork was conducted in the following surveys:
14
Main Survey (for relatively undisturbed natural communities) Railroad Prairie Survey
Cemetery Prairie and Savanna Survey
Endangered Species Survey
Relict Species Survey
The surveys were usually conducted within individual counties, but it was sometimes more efficient to ignore county boundaries, as in the railroad
prairie survey and searches for hill prairies along rivers.
Each survey was a process of selecting potential natural areas, then determining which ones were significant. Each successive stage examined the remaining candidates in greater detail. The survey stages were as follows:
Compiling available information
Gathering background material
Contacting people and agencies Reviewing literature
Examining maps and aerial photographs Aerial survey Initial ground survey
Final field survey
The inventories of geologic areas, aquatic areas, and school natural areas relied on compiling available information, so the last four survey
stages usually were not conducted for these areas.
Offices and staff
The main office at the University of Illinois in Urbana housed the project director and usually two senior assistants, a secretary, and technical assistants. The state was divided into five districts with one or two natural area ecologists in each district. Most of the ecologists had a Master's degree in botany, zoology, or forest ecology. Ten field assistants were employed during the summer of 1976, and there were eight summer assistants in 1977. Most of the field assistants had recently completed or were enrolled in graduate studies in a biological science. Additional part-time staff was provided as needed by the Natural Land
Institute's office in Rockford.
15
Schedule
Pilot studies began in March 1975, and natural area ecologists were hired and began a 3-month training session in July. The first stages of the Main Survey (compiling available information, examining maps and aer- ial photos, aerial surveys, and initial ground surveys) began in Septem- ber 1975 and continued until June 1976. The final field survey of areas found during the first year's work was completed in the summer of 1976, and the Main Survey of the remainder of the state was completed during the following year. More training sessions and pilot studies were con- ducted as new parts of the project were started. The preliminary stages of the Railroad Prairie Survey were completed in late 1975, and the final field survey of railroad prairies was done in the summer of 1976. Ceme- teries were surveyed to find prairie and savanna remnants from August to October 1976. Most work on endangered and relict species was com- pleted in 1977.
Basic Principles
To the greatest extent possible within limitations of time and money and within the guidelines set by the Department of Conservation, the In- ventory conducted a thorough inventory of Illinois' natural areas. Making sure that areas were not overlooked was emphasized as much as describing
and evaluating the significant sites.
This project differed from many other natural area surveys in that the staff devoted much effort to searches for relatively undisturbed natural communities. Many techniques were developed for finding and evaluating high quality natural communities, and a large part of this re- port is devoted to these topics. This does not mean that information from existing sources was ignored or that the elements of natural diver- sity that occur in disturbed areas were slighted. A wealth of informa- tion was compiled from the work of others, including over 1,400 published references to biologically significant areas. Although the degree of disturbance was the criterion for identifying one category of natural area, 60% of the natural areas have significant features other than lack
of disturbance.
16
Instead of choosing natural areas and then deciding why they were im- portant, the project developed a list of significant features and then found occurrences of these features. A further step was taken by drawing natural area boundaries around the significant features to include the natural diversity of the site and to provide potential for protection of the features. If one significant feature occurred with another, then both were included in the same natural area, but each significant feature kept its separate identity and remained an independent reason for recog-
MabrALMs ela Sales
Information Requirements
The Department of Conservation requested certain items of informa- tion about each area, which were refined into the following data items. A description of each item and the source of the data are described in Section 13 and Appendix 17. Not every item was appropriate or was col-
lected for every category of natural area.
Baste tnformatton County Name of area Significant feature.--The reason why a natural area is significant
Exceptional feature.--A feature that adds to the value of a natural area
Preservation value score Evaluator
Date of evaluation
Locatton
Legal location.--Township, Range, Principal Meridian, section and quarter-quarter section
Access
Topographic quadrangle Stream system
Specific stream drainage Legislative district Municipality
Governor's Region
ily
Natural characteristics Altitude. --Maximum and minimum
Topography.--Physiographic unit, major topographic feature, and individual topographic feature
Geologic formation
Soil association.--Statewide classification and county classifica- tion
Natural community classification.--Natural community, community class, and Natural Division and Section
Rarity index.--For each natural community Diversity index
Natural quality.--Acreage of each natural community in each natural quality grade; description of natural quality
Total acreage of natural area
Society of American Foresters' forest cover type.--For each natural community, where applicable
Plant community.--For each natural community
Legal status and use Ownership type Number of ownerships Owner or custodian Use of natural area Use of surrounding land Nearest Standard Metropolitan Statistical Area (SMSA) Distance to nearest SMSA Number of nearby universities and colleges Name of nearest university or college Number of nearby Department of Conservation facilities Land management facility Manageability Management problem description Zoning of area Zoning of surrounding land Regional planning commission Forest preserve district
Conservation district
18
Legal status and use, cont. Preservation status
Attitude of owner or custodian toward preservation
Threat of destruction Discussion of preservatton values
Supplemental materials Species lists Vegetation sampling data Topographic map with boundaries Aerial photo with overlays Additional notes and other materials
Literature citations
PART II CONCEPTS AND TERMS
Part II explains the basic terminology of the Inventory. The categories of natural areas are described, as are the terms used to describe and classify natural areas. A clear under- standing of the concepts and terms in the following four sec-
tions is necessary to understand the rest of this report.
20
ee Be hie Se eT RC a
Plate 3. A canyon in Starved Rock State Park. This area on the Illinois River qualtfied as a natural area under five categortes. It has high qualtty natural communities, habitats with endangered and threatened spe- etes, and assemblages of relict spectes. The park contains outstanding bedrock outcrops, and porttons are dedicated as an Illinots Nature Pre-
serve.
21
Section 4. NATURAL AREA CATEGORIES
Introduction
The Inventory recognized seven kinds of natural areas. The seven categories, each defined by its significant features, are in Table l. The natural area categories are listed below, and they are further de- fined in Part IV.
Table 1. Natural area categories and significant features.
Natural area category Significant feature I. Ecological area High quality terrestrial or wetland
natural community
II. Endangered species habitat Habitat with endangered species
III. Relict species habitat Habitat with relict species IV. Geologic area Outstanding geologic feature V. Natural study area Nature preserve or land that is managed and used for natural science studies VI. Unique natural area Unique natural feature VII. Aquatic area Outstanding aquatic feature
Summary of Categories
Category I: Htgh quality terrestrial or wetland natural communities These areas have natural communities that are relatively undisturbed,
so that they reflect as nearly as possible the natural condition at the
time of settlement in the early 1800's. Areas in this category were cho-
sen because of their high natural quality, as explained in Appendix 22.
Category II: Habitats with endangered species These sites have vertebrate animals or vascular plants that are in
danger of extirpation from Illinois.
Die
Category III: Habitats with reltet spectes Sites were recognized as natural areas if they have outstanding as-
semblages of plants that are relicts of a past climatic period.
Category IV: Outstanding geologic features
Localities that are outstanding representatives of the state's geo- logic diversity were listed as geologic areas. In addition to natural features, artificial sites such as abandoned quarries could qualify as geologic areas. Category V: Wature preserves or lands that are managed and used for natural setence studies
Lands that are specially managed and used as natural areas for teaching and research or as nature preserves were included in this cate- gory, even though the natural communities might have been disturbed. This category includes areas such as dedicated Illinois Nature Preserves and
Federal Research Natural Areas, as well as areas maintained by schools.
Category VI: Unique natural features
A few significant natural areas did not fit into any of the above categories. These are sites of unique natural features, which are often small areas with unusual floristic, faunistic, or ecological features. Examples include (1) a cave with an outstanding invertebrate fauna, (2) a large bat hibernaculum, and (3) a cliff habitat that has an unusual as-
semblage of plants that cannot be considered endangered or relict species.
Category VII: Outstanding aquatic features
Some streams and lakes were listed as natural areas because they are relatively unpolluted and natural habitats for native aquatic life. These areas are distinct from Category I wetlands because the water quality and the fauna were the bases for recognizing the area; in contrast, the undis- turbed character of the vegetation was the primary consideration in Cate-
gory I wetlands.
23
Section 5S.
NATURAL AREA BOUNDARIES, LAND CONDITION CLASSES, AND FEATURES
Introduction and Summary
According to the Illinois Department of Conservation's definition, a natural area must be: (1) a tract of land or water, with a natural configuration or sufficient
buffer land to insure its potential for protection and proper management, that
(2) meets one or more of the criteria (described in Section 4) for rec- Ognition as a natural area, such as a relatively undisturbed natural community or an outstanding geologic feature.
The first part of the definition states that a natural area should have a natural configuration. That is, the boundaries of a natural area should coincide with the boundaries of natural features such as the edge of a forest, which may or may not be the same as artificial lines or boundaries such as a road. To insure that it has potential for protec- tion and proper management, a natural area may include land that has little natural value but is needed as buffer. Accordingly, a natural area may be divided into two land condition classes: matural land and buffer land.
The second part of the definition requires that a natural area must have at least one stgnificant feature, which is the reason for recogniz- ing a natural area. Other important features besides the significant
feature may be present in a natural area.
In summary, a natural area can be described according to its land
condition classes and features, outlined as follows:
Land condition classes Natural land Buffer land
Features Significant features Exceptional features Notable features
24
Artificial disturbance features Natural disturbance features The concept of natural quality and grades (Section 7) is important in the
discussion that follows.
Land Condition Classes
Natural land
The part of a natural area that is relatively undisturbed is termed natural land. It is defined according to natural quality, and it includes Grade A, B, and C natural communities. Although the boundaries of natu- ral land and the significant feature may coincide, natural land often ex- tends beyond the significant feature. When natural land does extend beyond the significant feature, it consists of Grade C natural communi- ties or Grade A and B stands that are too small to qualify as significant
features.
Buffer land
This consists of land within the natural area boundaries that is not natural land. Buffer land consists of Grade D or E natural communities that are included in the natural area to insure potential for protection
of the significant feature.
Applicabtltty of the land condition classtficatton
The land condition classes are mapping units based on natural quali- ty. The classes were mapped for Category I natural areas and Illinois Nature Preserves. For other kinds of natural areas, the only parts of the natural area that were mapped are the features described in the re-
mainder of this section.
Boundartes
Guidelines for determining the boundaries of the natural area, natu- ral land, buffer land, and significant features are detailed in Appendix 16. The rules for determining the boundaries of a natural area are sum- marized as follows: (1) Boundaries should be conservative, but adequate to include the sig-
nificant features and to provide potential for protection of the area.
25
(2) Natural area boundaries should follow the boundaries of natural fea- tures if possible.
(3) Acquisition factors such as access and monetary value of the land should not be considered.
(4) Boundaries should not be drawn arbitrarily.
Features
Any part or characteristic of a natural area is a feature. Although components such as topographic features and natural communities are also features of an area, this discussion is limited to the basic classes of features that were introduced above: Significant features, exceptional features, notable features, artificial disturbance features, and natural
disturbance features.
Stgntficant features
A feature that allows a site to qualify as a natural area of state- wide significance is a stgnificant feature. Table 1 lists the kind of Significant feature for each natural area category, and Table 2 gives examples of significant features. A natural area must have at least one Significant feature. The boundaries of a significant feature may coin- cide with the boundaries of a natural area, but the natural area often extends beyond the significant feature. For example, a tract may consist of a steep hillside with a mature second growth forest (not a significant feature) and a series of one-quarter to 2-acre Grade A hill prairies (the Significant features). The mature second growth forest is designated as natural land; but, in the absence of the hill prairies, the hillside would not be outstanding and the tract would not qualify as a natural
area.
Exceptional features
An exceptional feature is a feature that increases the preservation value of a natural area but is not important enough to be the reason for identifying a natural area. After a site was recognized as a natural area because of a significant feature, then the presence of exceptional features on the tract was recorded. A summary of exceptional features is
in Table 2.
26
“soinjeoays
‘oinjeojy OTQenbe yesrowoydy [esowoyde ydooxe ‘ainjeez otQenbe Auy
“9URDTFLUBTS apIM -a}e 4s JO ‘WRa1yS JO Oye, Butpuezsing “JIA
*9}IS [ROTSO[OAYIAe IO 9341S ITIOISTH *kLUOLOY
*QOURITFTUBTS
[euotse1 FO St ey. oInNjeaz [eanjzeU Tensnun 194,30 10 ody [Ios Tensnup
*Q0URDTJTUSTS [ROOT ‘1ouTU FO ST }eY} O1N}eOF [TeAINJeU TeNsnNUy
*QOUBITFIUBTIS aptmajzeys Jo ‘ainjeazy [eanqeu onbtun “IA
*aarasaid aInjeu & SEP poJeoTpap st .eYy} pur, 10
‘yoaresei pue Buryove} 1oj vere [einjeu
eB Se pasn pue paseuew st yey. pueT “A
“339 ‘poq [Issoy ‘aAeD ‘aansodxa yItToser 10 yD01peq Auy
*90URDTJIUSTS [TeUOTSaI FO ‘squetd JOTTeL JO aselquesse ue yIM 1eITGeH
*QOURITJFIUSTS OpTMaqeIsS FO ‘ainjesz ITZOTOeS Burpueysing ‘AI
“Q.URITJIUSTS aptmazeqs Jo ‘squetd JIT[eI FO aBe[quasse ue YIM JEITGeEH “III
“STOUTTT] UT [BOT *satoads IO oteit AIBA St YNq ‘paraduepue AT UsT yTensnun 10 atei ev YIM }eITQeH -ind JOU ST ey. Satoads Be YyIIM IeITGQeH
*(SaTQTunWWOS Ie, TUTS pue satiteid 10} o19e % uRYy. SssaT ing “sat TunwWod [TeIn}eu SOW TOF satoe ¢
qyseotT qe AT [e19Ues) pues eB pataptsuod
*AyLunuwod atiteid [es 2q TITS 0} ysnous o31e7T st (¢) ING
-njzeu e you fATuo squerd atatesg ‘atdwexe paqinjstp ysestT 10 ATuO ay. se Ajtyenb jou ssop (z) pue ‘aseere wnu
*saei2 y Mors pro -IULW oy} UPYI ToTTewWS st ([T) ey. set?
jo dnois [[ews IO TeNptAtpu] -Tunwwod [einjzeu g IO y apeiIg YIM Bory
aainjeaz aTqeiON aainjzeaz TeRuotzdadxy
*STOUT[T] Woz uoTJedi131x9 Jo Jasuep UI ST 3eYyi Satoeds eB YIM YPATGeEH “TI
*AYTunuMOD 1epnotqzed e Jo atduexo peqinjstp yseeyT 10 a[dwexa ATuo ayy se satjtyenb yey. (azts Jo ssaTpiresar) SoTjJTuNWWOD TeIN}eU D 2peIO YIM Peary
*AYTunuwod ietnotqszed e jo atduwexsa Ppeqinjstp yseel 943 10 atdwexa ATuo ay} se satzitjenb ey Inq ‘aseveroe wnU -IUIW oY} UPYI TeT[eWS ST Jey} SaTITU -nuwod Teinjeu g Io Y epety YIM vosy
*(saeTzTunwUOS
IayjO 10} satoe QZ pue ‘satatead
Io} o19e % ATTeNsnN) o3ea19e WNWTUTW
ay. spesoxe io sjTenba ey. satzTunW -wod [Rin}eu g IO Y apet YIM ePaoly ‘I
ainjeey JUBITJIUSTS *3eD
‘soinjeoy oTqejou pue ‘soinjzeoF [TeuoTydeoxe ‘soinjeoy jUuedOTFIUSTS Fo uostiedwoD “7 eTqeL
27
Significant features and exceptional features are equivalent to ele- ments of natural diversity in the State Natural Heritage Programs of The Nature Conservancy. The Heritage Programs make a distinction between elements and element occurrences: for example, the bald eagle is an ele- ment of our natural diversity, and an actual nesting site for bald eagles is an element occurrence (see Jenkins, 1978). Although the distinction between elements and element occurrences is important, the Illinois Natu- ral Areas Inventory usually applied the terms significant feature and exceptional feature to both the abstract concept and the real occurrence.
The meaning is usually clear by the context in which the terms are used.
Notable features
A notable feature is any feature of a natural area that is less im- portant than a significant feature or an exceptional feature. A notable feature does not increase the preservation value of a natural area, and recording the presence of a notable feature was optional. The summary of notable features in Table 2 is incomplete because many features may be
listed as notable.
Artificial disturbance features
Cultural features such as roads, trails, fences, buildings, and pow- er lines are artificial disturbance features. These are local disturban- ces, as opposed to broad disturbances that lower the natural quality of a natural community. For example, a narrow pipeline right-of-way is a disturbance feature, but a cultivated field is a Grade E area, not a lo- cal disturbance feature. Similarly, a drainage ditch in a marsh is a disturbance feature; but the entire wetland is not a disturbance feature,
even though the ditch may lower the natural quality of the marsh.
Natural disturbance features
Examples of natural disturbance features are (1) a stand of trees killed or damaged by a windstorm, fire, insects, or disease, (2) an area flooded by a beaver dam, and (3) a stand of shrubs invading a prairie. These are considered natural disturbance features because they are the results of natural agents, even though the disturbances may be attributed indirectly to human activities. In the above examples, the fire may have
been started by a person; the disease, insects, and beavers may have been
28
introduced by humans; and the woody invasion may be the result of unnatu- ral fire suppression. However, since the disturbances result from natu- ral processes instead of direct human activities, they are considered
natural disturbance features.
29
Section 6. NATURAL COMMUNITY CLASSIFICATION
Summary
The Inventory's classification of natural communities was a basis for identifying Category I significant features, and it was used to clas- sify all natural areas. The classification system is detailed in Appen-
dix 30 and is briefly reviewed in the following paragraphs.
The natural community classification uses the concept of the Natural Divistons of Illtnots (Schwegman, et al., 1973), which recognizes regions of the state on the basis of topography, glacial history, bedrock, soils, and the distribution of native plants and animals. A map and a brief description of the Natural Divisions are in Appendix 30. The Inventory's classification further subdivides the Natural Divisions and Sections into nine community classes:
Forest
Prairie
Savanna
Wetland
Lake and Pond
Stream
Primary
Cave
Cultural
The smallest unit in the classification is the natural community, which is a subdivision of a community class. A natural community is a group of organisms interrelated with each other and their environment. Although a natural community might be defined at any scale, it was used as the smallest unit of land or water that could be mapped on large-scale
(1:7,920) aerial photos.
Natural communities were classified and named by considering a vari- ety of natural features and choosing the dominant features that distin- guish one community from the others. One or two important descriptive features are usually included as modifiers in the natural community name,
as in dry sand savanna.
30
There are 93 different kinds of natural communities (Table 38), in- cluding eight cultural communities. Each Natural Division and Section has its own, distinct set of natural communities, and the name of the Natural Division and Section is part of the natural community name. For example, a dry-mesic prairte of the Springfield Section of the Grand Prairie Divi- ston is a community distinct from a dry-mesie prairie of the Western Sec- tion of the Grand Pratrie Diviston. For practical reasons, the shortened name, dry-meste prairie, is used unless a distinction needs to be made be-
tween communities in different Natural Divisions or Sections.
an
Section 7. NATURAL QUALITY
Summary
Natural quality is defined as a measure of the evidence of distur- bance to a natural community. The Inventory used the relative lack of disturbance to identify Category I significant features, and described the degree of disturbance of all communities in all natural areas. A system of letter grades was developed to express degrees of natural qual- ity. The grading system is based on degree of disturbance, alone: other factors such as acreage and the presence of endangered species were not considered when determining natural quality. Although these other fac- tors are important for determining the overall preservation value of a natural area, they were kept separate so that natural quality described
only the degree of disturbance.
The grading system provides terms for describing the relative amount of successional instability or change in a community's natural diversity, species composition, and structure due to disturbance. The grades are
summarized as follows:
Grade A: Relatively stable or undisturbed communities. Example:
Old growth, ungrazed forest.
Grade B: Late successional or lightly disturbed communities.
Example: Old growth forest that was selectively logged 5 years ago.
Grade C: Mid-successional or moderately to heavily disturbed com-
munities. Example: Young to mature second growth forest.
Grade D: Early successional or severely disturbed communities.
Example: Severely grazed forest of any age.
Grade E: Very early successional or very severely disturbed com-
munities. Example: Cropland.
The natural quality grades are described in more detail in Appendix 22. Some procedures for evaluating and describing disturbances are in Appen- GIL eZ1
yz
t akenen ; x aSeeaveers? hbvssien , S$ 1 aS LRM wd Oop ware it i Ae ays cine -» we bal =e dodo
; = “Tein etsssm 2 2s bsiicsh zt wzbipun ion a
hs Snsvni seit ssmamang Letul ta 4 oF
moitinnie ) con 9te') hans) oF eonnga
sat stiianmon ite to wanndtursth 2e
1 bouolevel suw febets ste! esorgeb fo beaed af mojeve $fibatg sonsesig Sit-bak ogguria az fous ¥
wION Barat wT 30h) Satlw borabke
a) } gv inisretsb 202 Jnesougel or Jest o2 ote2oune IJqed excw yanks ,eon0 .eotedzuset to ssqyeh ohF ¥E b $1. debi 1 msJeye Gotharg SAT = = it io % ‘idesznl ieieleesooue t is afar Be us ,foi i isequcs perros wolfe? gabe { u xo sidete vylevizalah tAehad
.Jesi102 besergey \dewoTty O10
riysigil +o L[anoteenoote 37h) (8 She A —
a Bs JeoTo? ee | 51D sal 3 | a &
te2eooua-biv 20) See rolqmezh . »23l
62 TO [ano eC 32Me ita ive
=) , aa & rowed
tery Yieoreved
one yling Gara 44 abe walqor? ssi esty
Vaup tau:
sh ora eobham yobieup tes
gorsauleye ret eon 7 ~ ..
_
. rs
iv
nidftoted Ofe
PART III METHODS
This part of the report describes the stages of the inventory
and the items of information collected for each area.
34
y q LA
iE -| @
re
. oY : (B)
poet et 4 Ps Pe el
y OQ.
bee a ee oe
\)
es os |
N at
\)
Ane A Hi 7 _PRAIRIE
histetc\s ZY
"ae Ay i oer t
i \ “15 4 oid 17 Ic « 7] U o
Plate 4. A sectton of the Presettlement Vegetation Atlas of Illinois. The maps were used to select cemeteries to survey for prairie renmants. For example, the cemetery at A ts more than a mile instde the forest, and has no potenttal for pratrie vegetation. The cemetery labeled B is on pratrie sotl, one-half mile beyond the limits of the forest. The rear of thts cemetery has a remnant of nattve prairte vegetation.
a a
Plate 5. An example of an aertal photo used to select potential natural areas. The tract labeled A shows evtdence of grazing damage: the trees are widely scattered, and whitish livestock trails extend into the trees from a stock pond (B) and a barn (C). The timber stand labeled D has a dense, even canopy of large-crowned trees, indicating an old, undisturbed
forest.
35
Section 8. COMPILING AVAILABLE INFORMATION
Purpose
Information was gathered from sources such as publications to (1) identify natural areas, (2) compile resources that would aid the search for areas, and (3) collect information that would help describe and eval-
uate areas.
Procedure
Gathering background matertal
This involved obtaining soil reports, maps, unpublished reports, and Similar information, usually related to specific counties or areas. Much information was from the Illinois Nature Preserves Commission, Department of Conservation, and Natural History Survey. Work in cooperation with the Illinois Endangered Species Project to find records of endangered
species in herbaria and museum collections is described in Section 17.
Contacting people and agencies
As part of the survey of each county, the fieldworkers asked the following professionals for information about natural areas: district foresters for the Department of Conservation, district conservationists for the Soil Conservation Service, and county executive directors for the Agricultural Stabilization and Conservation Service. The staffs of for- est preserve districts and conservation districts were also contacted. Enquiries often led to other citizens who knew about natural areas in a particular region. Other people with known interests in natural areas
were contacted, especially faculty members at colleges and universities.
General publicity
The Inventory was widely publicized to solicit information about natural areas. The Department of Conservation taped five interviews during various phases of the project and distributed the tapes to about
80 radio stations. There were two live radio programs, a television
36
presentation, four statewide news releases, and several articles in news- letters and local newspapers. The staff presented 27 talks, attended by an estimated total of 2,000 people, at conferences, universities, and
meetings throughout Illinois. Schwegman (1977a, 1977b) and Madany (1977)
wrote feature articles about the project.
Iiterature revtew The literature review is listed here as a part of the process of com- piling available information, but it was such a large effort that it is
discussed separately in Section 23.
Results
Compiling background information was a necessary preparation for the rest of the inventory, and it revealed some previously unrecognized natu- ral areas. Because many Inventory staff members were already familiar with the files of the Department of Conservation, Natural History Survey, and Nature Preserves Commission, the amount of new information gained from these files cannot be determined for certain. However, collecting and organizing these resources provided a sound background for further work. The amount of information gained from various conservation-related agencies varied according to the personal knowledge and interests of the individual contacted. Faculty members at colleges and universities and amateur naturalists were the most valuable sources of information about potential natural areas in many counties. General publicity efforts through the news media and presentations to groups yielded very little new information about significant natural areas, but it did make more people aware of the Illinois Nature Preserves System. The effectiveness of compiling existing information for finding and screening potential natural areas is discussed in relation to other stages of the inventory
in Section 24.
37
Section 9. EXAMINING MAPS AND AERIAL PHOTOGRAPHS
Introduction
Maps and aerial photos of each county were systematically examined to (1) select potential natural areas, (2) determine what land had no Significant potential for natural areas, and (3) map, describe, classify,
and evaluate the identified natural areas.
Topographic maps were the basic maps used by the Inventory. There are many useful sources of information about the use of topographic maps, including publications by the U. S. Geological Survey (1969), Beveridge, et al. (1957), Cote (1967), and the U. S. Department of the Army (1969). Atlases by DeBruin (1970) and Richason (1972) provide excellent illus- trations of representative geologic, vegetation, and cultural features on
topographic maps.
There are also many useful references about aerial photo interpre- tation. Books by Strandberg (1967), Avery (1968), and Way (1973) are among the best sources of information about using aerial photos; and Avery (1969) provided a practical discussion of interpreting aerial photos of forested land. The following atlases have examples and de- scriptions of geologic features, vegetation patterns, and cultural fea- tures that are relevant to Illinois: Ray (1960), Wanless (1969), Richa- son (1972), and Baker and Dill (1970, 1972).
Map Resources
Topographic maps
The project used 7.5-minute U. S. Geological Survey quadrangles with forest overprint when available, but only the 15-minute series is available for about 40% of Illinois. The 15-minute maps were studied in addition to the 7.5-minute maps when both were available, because many
of the 15-minute maps date from 1910-1940 and they show old clearings,
38
homesites, roads, and other disturbances that may no longer be shown on
the 7.5-minute series.
Highway maps
County highway maps produced by the Illinois Department of Trans- portation proved useful for general planning, summaries, and aerial navigation. The maps are available at the scale of 1 inch equals 2 miles, and a bound atlas of smaller-scale copies of these maps is commercially
available.
Presettlement Vegetatton Atlas of Illinots A set of county maps showing presettlement vegetation based on the original Public Land Survey was used to find areas with potential for
prairie vegetation. The atlas is described in Appendix 19.
Soil maps
The soils of almost every county have been mapped. The county soil maps vary in age, quality, and detail. The general soil association maps were most helpful for finding unusual kinds of soils. A small-scale state soil association map by Fehrenbacher, et al. (1967) was used for a
uniform, statewide classification.
Geologic maps
The Geologte Map of Illinois by Willman and others (1967) was ef- fective at 1:500,000 scale for much of the work. Detailed surficial geologic maps for most areas of Illinois that have bedrock outcrops are available in Master's theses and Illinois State Geological Survey reports
and files.
Aerial Photographs and High-altitude Images
The Inventory relied on relatively low-altitude, conventional black and white aerial photographs as one means to find, evaluate, describe, map, and classify natural areas. This section describes the aerial photos and briefly discusses the advantages and disadvantages of the various kinds of aerial photos and other remotely sensed images. All kinds of terrain imagery, from low-altitude aerial photos to satellite
"images'' (which are not photographs) are classified as remote sensing.
39
Sabins (1978) presented a comprehensive and recent analysis of remote
sensing techniques.
ASCS aerial photographs
The Agricultural Stabilization and Conservation Service (ASCS) of the U. S. Department of Agriculture periodically produces aerial photo- graphs of every Illinois county. The land is photographed during the growing season on panchromatic black and white film, with a minus-blue filter. The negatives are 1:20,000 scale, and the photos overlap to allow stereo viewing. Contact prints from the most recent flights are on file at the state ASCS office in Springfield; the ASCS office in each county has a set of enlargements at the scale of 1:7,920 (8 inches equals
1 mile, or 1 square inch equals 10 acres).
The ASCS enlargements are of good quality and were suitable for the Inventory's needs. Many vegetation and cultural features are easy to recognize, and resolution is adequate. Ground resolution is usually 2 to 3 feet (U. S. Department of Agriculture, Economic Research Service, 1969), and the smallest object that can be identified without some clue such as its relation to its environment is about five times the ground resolution (Strandberg, 1967). For example, cattle can sometimes be identified on ASCS photos as light-toned, rectangular features at feed bunks and watering tanks. Linear features and objects that contrast with their surroundings are most readily distinguishable. For example, the faint pattern of lines in a field plowed several years ago is often visi- ble, and the crown of a solitary tree is distinguishable. Under unusual circumstances even the painted center stripe on a highway or large elec-
trical transmission cables can be seen.
ASCS photographs are taken of each county about every 7 years, and the earliest photos of most counties were taken between 1938 and 1941. These earlier photos are valuable because they show how an area appeared in the past. The county ASCS offices keep enlargements from at least one previous flight, and university libraries receive the outdated con-
tact prints.
40
Other aertal photographs
Other kinds of aerial photos are available for parts of Illinois, but only ASCS aerial photos were used by the Inventory, mainly because the resolution of other photos is not fine enough or the photos are not widely available. Infrared color photos (also known as false-color infra- red) would have been preferred instead of ASCS panchromatic photos, be- cause the infrared film provides better contrast among vegetation types and better detection of wetlands. However, infrared photos are not easily obtained: they have been taken of only small parts of Illinois for specific projects by agencies such as the U. S. Army Corps of Engi- neers. The state has been photographed from high-altitude military aircraft and spacecraft, but the coverage is incomplete, the scales vary, and ground resolution is much less than for low-altitude aerial photos. Other low-altitude black and white photos, similar to ASCS photos, are available from agencies such as the U. S. Geological Survey. However, coverage of the state is incomplete, the photos are not easily obtained,
and most are winter photography, which greatly limits vegetation analysis.
Landsat tmages
Interest is developing in satellite imagery as a means of studying natural resources since the launching of the ERTS-1 satellite in 1972. Two more satellites (now named Landsat) have been launched, and the Na- tional Aeronautics and Space Administration has supported research to evaluate uses of Landsat imagery. Williams and Carter (1976) edited a collection of papers describing such Landsat research in many disci- plines, including vegetation mapping. Relatively nontechnical publica- tions that are helpful for learning about Landsat imagery are by Dickson (1977), Short, et al. (1976), and Lineback (1975). The Illinois Environ- mental Protection Agency (1978) presented a basic explanation of Landsat
images and their use.
Landsat has a low resolving power, which limits its usefulness for natural area inventories. Relatively small or narrow features with great contrast (such as highways) can sometimes be detected, but pro- cessed images usually have a ground resolution between 200 and 250 me-
ters. The recently launched Landsat 3 reportedly has better resolving
41
7
power than the earlier satellites, but even these new images would not have been suitable because the Inventory workers needed to see thin graz- ing trails and the gaps in the forest canopy caused by the removal of Single trees. In a test of ERTS-1 imagery, Fentress and Frye (1975) were able to map land in a Texas county with 10 land use or cover classes, portraying every fifth picture element (57 meters by 79 meters), with 82% accuracy. In contrast, the Inventory staff did not map large areas, but studied areas smaller than one picture element, recognized a practically unlimited number of land use and vegetation cover combinations, and
strived for 100% accuracy.
Landsat images are useful for regional surveys, broad classifica- tions, small-scale maps, and detection of large, faint surface features. They allow a quick, general overview of an area, but they cannot replace topographic maps and large-scale aerial photos for finding and describ-
ing natural areas.
The satellite images have a feature that might be used to an advan- tage: Landsat records the sunlight reflected from the earth in four spectral bands. Different kinds of earth, water, and vegetation reflect sunlight differently, so some features are more apparent on one spectral band than on another. By processing images in certain ways, certain vegetation types are most vividly portrayed. Despite problems with low resolution, Landsat images do have potential for determining unusual habitats and natural communities of limited extent. By choosing the cor- rect season, light wavelengths, and processing, it might be possible to find a unique spectral reflectance, or "signature" to identify prairies. Although there is much potential for study in this field, the Inventory found no need for detailed experimentation because standard map and aer-
ial photo interpretation techniques worked well.
Procedure and Results
Examination of maps and aerial photos was conducted within individ- ual counties and proceeded by legal township and section. The procedures for detecting natural areas and disturbances on maps and photos are dis-
cussed in Appendix 21. Areas that had potential as significant natural
42
areas were outlined and numbered on topographic maps. Brief notes about the potential natural areas as well as the disturbed areas were recorded
on the maps and on forms.
After the current ASCS enlargements were reviewed, the potential Category I natural areas were examined on the oldest available ASCS photos. The old photos (often as early as 1938) showed previous distur- bances not apparent on the newer photos, and they helped the investigator
to interpret apparent disturbances detected on the newer photos.
The 1:7,920 scale aerial photo enlargements available in ASCS offices were used for the main screening instead of contact prints because sig- nificant details can be overlooked on contact prints. Although the en- largements have no more detail than the contact prints, studying the enlargements is less tedious and causes less fatigue and eyestrain.
Other advantages of using enlargements were: (1) the photos were the most recent available, (2) acreages of some tracts were marked by the ASCS on the photos, and (3) using the aerial photos in the county ASCS office provided an opportunity to talk to local people and to check areas
during the examination procedure.
The map and aerial photo examination required from 3 to 5 days for a typical county, and usually 20 to 40 potential natural areas were found. In a few counties the procedure required less than a day, and no areas were found. A few counties with many wetlands required 2 or 3
weeks of study and resulted in over 100 sites to be checked.
43
Section 10. AERIAL SURVEY
Purpose
The aerial survey was a means of (1) screening potential areas, (2) finding new areas, and (3) determining boundaries and characteristics of
natural areas.
The aerial survey was an extension of the map and aerial photo exam- ination stage. It provided a closer and more recent view than possible with maps and photos, and it allowed fieldworkers to reject many non- qualifying areas quickly, without completing the time-consuming initial ground survey. New areas were found and areas were studied in a detailed manner not possible with maps and photos. The aerial survey allowed a
quick comparison and overview of many areas in a short time.
Procedure and Results
General techniques
Cessna 172 aircraft were used, which are single-engine, four-seat airplanes with high wings. Areas were viewed generally by flying as slowly as practical and safe (80 to 90 miles per hour), at 500 to 800 feet above the ground. Between sites, the planes could cruise at 110 to
120 miles per hour.
Before each flight, the sites to be checked were marked on a county highway map, and a flight plan was drawn on the map. Topographic maps with the sites outlined were also assembled, and Potential Natural Area Record Forms were put in order so that notes could be recorded for each area. The tracts usually were observed while circling each site from one to four times. Emphasis was placed on noting disturbances and spe- cial features, refining boundaries, and deciding whether the site still qualified as a potential natural area. Effective surveying from an air- plane came with practice. Efficiency was gained by studying areas from
an airplane that were already well known to the investigator. Knowing
44
the actual size of certain objects on the ground helped the surveyor to
make other size estimates from the air.
Examples of techntques Clues for identifying disturbances and natural communities are de- tailed in Appendices 20 and 21. Following are examples of how an air-
plane was used for finding natural areas.
Surveying from an airplane was useful for determining the boundaries of a natural area, which may differ from preliminary boundaries from aer- ial photos. The photos may not show some disturbances clearly, or the disturbances may have happened since the area was photographed. For instance, by circling 2,000 feet above a 1,000-acre swamp, fieldworkers were able to accurately and precisely map the extent of recent clearing and logging. In 14 minutes a task was accomplished that could not have been done as well on the ground, even with 2 days work by a two-person
team.
Although most forested natural areas were found by examining aerial photos, the aerial survey was sometimes helpful for determining the exact boundaries of the highest quality stands of timber in large tracts of mature forest. The exact boundaries of the oldest stands of trees cannot always be delimited precisely from aerial photos if the forest in general is mature and has a natural structure. For example, there are many square miles of forest along the lower Kaskaskia River--mostly logged at various times and to different degrees, but with large, well formed trees because the land is so productive. The most promising tracts along the Kaskaskia were outlined from aerial photos, but the extent of some of the tracts was uncertain because the largest-crowned trees seemed to in- tergrade with younger stands. Bur oaks are common in the floodplain, growing on all but the wettest soil, and any tract of old growth bottom- land timber in the region has large bur oaks. The task during the aerial survey was to select stands with large bur oaks, which are easy to dis- tinguish from an airplane in the winter because they have thick, grayish
limbs and twigs.
A technique similar to the preceding was developed during surveys
over the Shawnee Hills. Old growth stands of dry upland forest could be
45
detected by spotting groups of very old post oaks. These trees have large crowns with gnarled, spreading limbs. They are easy to see from an airplane because the limbs are covered with greenish lichens. As with the bur oaks in the floodplain, the staff was able to find the old growth dry upland forests by searching for large, old post oaks after narrowing
the possibilities by examining aerial photos.
Hill prairies occur along major river valleys on dry, exposed slopes, and they are highly visible from an airplane. Although hill prairies can be found by studying maps and aerial photos, it was not necessary to find every potential prairie before the aerial survey. Instead, the ecolo- gists decided which sections of river valleys had potential for prairies, and flew along the bluffs marking the location of every hill prairie.
The fieldworkers noted the ones that appeared to be relatively undis- turbed and had potential as natural areas. Along some stretches of river bluff, color slides were taken of the prairies as an aid for finding
small prairie openings on the ground.
Sand prairie remnants occur on plains along major rivers in central and northern Illinois. By examining aerial photos and soil maps it was possible to mark on topographic maps the uncultivated, grassy areas on sandy soil that were not obviously disturbed by grazing. The aerial sur- vey was a systematic search of sand areas, examining the sites chosen by the map and photo examination and looking for small remnants that were not apparent on the photos. The disturbed areas were rejected, and color
photos were taken of the largest sand prairies to aid the ground survey.
Natural seep communities occur along major rivers, so the aerial survey of seeps shared some basic techniques with the search for hill prairies. In the winter, seeps appear as prominent blackish patches, especially if the surrounding land is snow covered. (The ways in which snow enhances features observed from an airplane are discussed in Appen- dix 21.) Seeps sometimes are dark green because of horsetail colonies or emerald green because of water cress. By surveying after a light snow- fall, it was possible to find the seeps along the 200-mile length of the
middle Illinois River and lower Sangamon River in less than 5 hours.
46
Effectiveness
An average of 10 to 12 sites could be viewed in an hour from an air- plane, which is the number that could be visited in 2 to 4 long working days on the ground. The potential natural areas in most counties could be surveyed from the air in 1 to 3 hours, but some counties required as many as 8 hours. Between 50% and 90% of the areas in an average county were eliminated during the aerial survey. In some counties, several new sites were found from the air. Although the aerial survey accounted for less than 5% of the survey budget, surveying without an airplane would have required seven to 10 times as much time and seven to 10 times as much money for fieldwork, and it would not have been possible to accomp-
lish some tasks and find certain areas.
There were some difficulties with scheduling flights and with air- sickness. The weather was suitable for flying only about half the time. Flights were often scheduled a wegk in advance, so a cancellation caused inconvenience and lost time, particularly since other activities had to be scheduled around the flight. Planes and pilots were hired from sever- al different airports, and it took some effort to find pilots that pro- vided reliable and skillful service. Circling in an airplane and studying areas intensely can cause airsickness, but the problem could be avoided by flying on calm days, circling gently, and taking airsickness
drugs. The fieldworkers became less prone to sickness with experience.
In Lake, McHenry, and Cook counties, where there are many complexes of prairies and wetlands, an airplane was not as effective as desired because it was too fast. A helicopter was used for about 8 hours to sur-
vey these areas.
47
Section ll. INITIAL GROUND SURVEY
Purpose
The purpose of the initial ground survey was to prepare for the fi- nal field survey by evaluating the sites selected during prior inventory stages. The initial ground survey also served to check the accuracy of the map and aerial photo examination and the aerial survey, and it was
used to develop techniques for the final field survey.
Procedure
Initial ground surveys were conducted only for Category I areas.
The surveys were completed during the dormant season so that the summer could be reserved for final field surveys. Other advantages to doing the initial ground survey in the late fall, the winter, and early spring were: (1) interspersing initial ground survey work with aerial surveys helped the fieldworkers develop their field evaluation techniques, (2) general surveys of forests were easiest when they were leafless, and (3) surveys of wetlands were quicker when they were frozen. Initial surveys were not made for potential endangered and relict species sites because these were usually small areas that required searching habitats during
the spring and summer months.
During the initial ground survey the fieldworkers determined whether a potential natural area was significant. If an area was not significant, it was investigated only enough to record the reasons why it did not qual- ify. Significant areas were surveyed in more detail, to define the bound-
aries and locate features so that the final field survey could be planned.
Results
About two-thirds of the potential areas were rejected during the initial ground survey of a typical county. About 15% of the rejected
sites were recorded as notable areas, of local significance.
48
Section 12. FINAL FIELD SURVEY
Final evaluation, description, and classification of each natural area were completed during the final field survey. The information was
recorded as described in the following paragraphs.
Main Data Form
Standard information was recorded on a Main Data Form, which is de- scribed in Section 13 and Appendix 17. If an area was not visited, then the Main Data Form was completed by using information available in the office. Some items on the Main Data Form (such as the legislative dis- trict) were not determined during the final field survey, but were com-
pleted, later an) the office:
Maps and Aerial Photographs
The boundaries of the natural area were drawn on a copy of a topo- graphic map. If an area was an Illinois Nature Preserve or had a Cate- gory I significant feature, then the natural communities, natural quality, land condition classes, and other features were mapped with over- lays on aerial photos. For other kinds of natural areas, topographic maps or sketch maps were used instead of aerial photos, and less detail
was mapped.
Vegetation Sampling
Plant communities in Category I significant features were sampled to help determine the dominant species and to help assess the natural qual- ity of the communities. In herbaceous communities, species frequency data were gathered from 20 or 30 one-quarter square meter circular quad- rats in each plant community. Sampling techniques for forests were influenced by research by Lindsey, et al. (1958) and Ohmann (1973). Basal area was measured with a 3-basal area factor metric wedge prism (see
Avery, 1967; Hovind and Rieck, 1970) at 20 points in each plant community.
49
Density of the overstory was recorded in l-decimeter size classes in 0.025- hectare circular plots centered at each sampling point. Density of woody plants taller than 1 meter but less than 1 decimeter in diameter at 1.2 meters above the ground was recorded from a 0.00l-hectare circular plot
at every other sampling point. Absolute and relative values were calcu- lated for the data. Initially, sampling points and plots were random, but later a systematic grid pattern was used to give a more even distribution of sampling points and to simplify fieldwork. A total of 492 stands were
sampled.
Species Lists
Checklists were completed for amphibians, reptiles, birds, mammals, ferns and fern allies, and woody plants. In addition to ecological samp- ling of herbaceous communities, the vascular plants in prairies, glades, and wetlands were listed. Some high quality communities that could not be sampled with standard techniques (such as cliffs) were described with detailed plant species lists. A total of 2,511 species lists were com- pleted. The relative abundance of each species was recorded as described
in Appendix 29.
50
SEGtrony lS.
INFORMATION COLLECTED ABOUT THE NATURAL AREAS
Main Data Form
The following numbered items appear on the Main Data Form, which was completed for each natural area. A Main Data Form and instructions for completing the form are in Appendix 17. A description and the source of each item are given below unless the meaning and source of the data can be
understood from the instructions in Appendix 17.
Not every item was collected for every area. For example, aerial photos with detailed overlays were completed only for areas with Category I significant features and for Illinois Nature Preserves. The boundaries and features of other kinds of natural areas usually were shown only with
topographic maps and sketch maps.
Data for all items except those designated by a prime mark (') were computerized. Items designated with two asterisks are numerical values that can be analyzed with the computer's statistical programs. Items marked with one asterisk are encoded for computer searches and retrievals, but univariant statistics do not apply directly to these items. The re- maining items are computerized as text, and they can be displayed but not
analyzed by the computer.
(1) Index number (*).--An index number was assigned to each natural
area by the computer. The number is used in computer operations. (2) County (x)
(3) Reference number.--This number, in combination with the name of the county, is a unique identifier for the area. Reference numbers were assigned by the fieldworkers to identify areas in each county. Because all potential natural areas were assigned reference numbers, there are usually gaps between reference numbers for natural areas in the same county. For example, the two natural areas in Piatt County are Piatt 6 and Piatt 9 because numbers 7 and 8 were assigned
to potential natural areas that were rejected.
(4) (5) (6) (7)
(8) (8') (9)
(9") (10)
(11)
(12) (13)
(14)
51
Natural area name Natural area categories and significant features (*).--See Section 4. Excepttonal features and notable features («*).--See Section 5.
Preservation value score (**).--This gives the evaluator's overall judgment of the value of preserving an area. The Department of Con- servation requested that no guidelines be developed for determining the preservation value score, but that the evaluator record an esti- mate of the site's value relative to other natural areas. The pres- ervation value score ranges from a low of 1 to a high of 5. (See
Appendix 27.) Evaluator Date of tnvestigation
Legal locatton.--Location was recorded by section, Township, Range, and Principal Meridian. Each quarter-quarter section that included part of the site was recorded. The information was encoded for com- puterization, and the computer displays the information to the nearest quarter section. Also, the quarter-quarter section that includes the center of the area was encoded and computerized for a
possible future computer mapping program.
Access
Topographte quadrangle (x)
Strean system (*).--This item was termed watershed on the Main Data Form. Each natural area was classified according to the stream sys- tems recognized by Smith (1971). The source for determining the stream system was a 1:500,000 scale base map of Illinois. (See Appendix 10.)
Spectfie strean.--Source: Topographic map.
Legislative district (*).--Source: Legislative district map.
Municipality. --Source: County highway map or topographic map.
(1S) Altttude (**).--Source: Topographic map.
52
(16) Topography (*).--The physiographic unit, major topographic feature, and individual topographic feature were recorded according to the
classifications in Appendices 4, 5, and 6.
(17) Geologie formation (*).--Dr. H. B. Willman of the Illinois State Geological Survey determined the geologic formation for most natu- ral areas from geologic maps, Geological Survey files, personal knowledge, and information recorded by the fieldworkers. Bedrock formations were recorded only if they were exposed. (See Appendix Hs),
(18-19) Soil assoctatiton («).--To determine the soil associations in each natural area, the staff used the Sotls of Illtnots book and statewide map by Fehrenbacher, et al. (1967) and county soil asso- ciation maps available either in county soil reports or as separate maps. Both the county reports and the statewide reports were used because each had its own advantages that partly offset the disad- vantages of the other. The statewide treatment in Sotls of Ilit- nots (Appendix 8) provides the only complete map and uniform classification of soil associations in Illinois, but the classifi- cation is generalized (26 associations) and the map is small. The county soil association maps are more detailed (often 10 to 20 associations in one county), but the equivalent association is often given different names on either side of a county line. As a result, the county soil association maps were considered to be relatively detailed and descriptive, but not part of a uniform classification system. The more general state soil association map was used to provide a uniform system for classifying soils in natural areas
statewide.
(20) Natural community classtfication (*).--The term community-type on the Main Data Form was changed to community class in the final natural community classification system. (See Section 6 and Appen-
dix 30.)
53
(21) Rarity index (**).--This is an estimate by the fieldworker of the
(22)
(23)
(24)
(25)
abundance of each natural community relative to its presettlement
extent. The index ranges from 1 for abundant to 5 for very rare.
Diversity index (**).--This is a count of the number of natural
communities in the natural area that have a natural quality of Grade’ “A,B; “or C.
Natural quality
(a)
(b)
Acreage of natural communtttes by grades (**).--If the natu- ral area was mapped with overlays and an aerial photo, then the acreage of each community in each grade was measured with an area measurement grid. If the acreages were not measured, then a "'P" for "present" was entered, and the computer dis- plays the word "unknown" instead of an acreage figure. Deseription of natural quality.--Source: Field observations, aerial photo interpretation, and other sources such as dis-
cussions with landowners.
Total acreage (**).--Sources: Measured with a grid from an aerial
photo or topographic map, or occasionally taken from a plat book.
Vegetation types
(a)
SAF cover type (*).--When applicable, each plant community was classified according to the Society of American Foresters' (SAF) forest cover type (Society of American Foresters, 1967). The cover type was determined by field observations or vege- tation sampling, but the classification was difficult to apply to this inventory for four reasons: (1) The definitions of some cover types are not broad enough to accommodate some communities. (2) The cover types are sometimes biased toward trees of economic importance. (3) Secondary successional com- munities are sometimes in the same cover type with stable, un- disturbed communities. (For example, the red cedar--hardwood cover type is applicable to both abandoned farmland and sand- stone glades.) (4) The "predominant" species in a cover type are supposed to be determined by density, but density was
found to be so misleading that dominance was substituted. A
54
(26)
(27)
key to SAF cover types in Illinois was prepared to aid the fieldworkers. The SAF cover type classification is being revised, but the Inventory used the current classification because it is widely used in other natural area information
systems. (See Appendix 9.)
(b) Plant community («).--Sources: Field observation, vegetation
sampling, aerial photo interpretation, and published studies.
Ounershtp type (*).--Sources: Plat books or information gained by
fieldworkers.
Number of owners (x«).--Sources: Plat books or information gained
by fieldworkers.
(27') Owner or custodian
(28)
(29)
(30)
(31)
(32)
(33)
(34)
Use of natural area.--Sources: Field observation, maps, and aerial
photos. (See Appendix 11.)
Use of surrounding land (*«).--Land use within 1 mile of the bound- aries of each natural area was estimated according to three categories:
(a) Wildland (forest, natural aquatic areas, abandoned farmland) (b) Farmland (cropland, pastureland, orchards, farmsteads)
(c) Developed land (towns, factories, quarries, reservoirs) Maps and aerial photos were the sources of the estimates.
Nearest SMSA (*).--Source: Standard Metropolitan Statistical Areas
(SMSA's) were drawn on a 1:500,000 scale map of Illinois. Distance to the nearest SMSA (**).--Source: Same as item 30.
Number of nearby schools (**).--Source: The location of every aca- demic college or university was drawn on a 1:500,000 scale map of
Illinois. Nearest school (*).--Source: Same as item 32.
Number of nearby DOC faciltttes («*).--Source: The location of every Department of Conservation (DOC) land management facility was
marked on a 1:500,000 scale map of Illinois.
55
(35) Land management facility (*).--This is any agency that is an actual or potential manager of the natural area (Appendix 13). Sources: (1) Illinois Department of Revenue tax maps showing the boundaries of park districts, river conservancy districts, soil and water con- servation subdistricts, forest preserve districts, and conservation districts, (2) plat books, (3) other maps showing the holdings of major land management agencies such as the U. S. Forest Service, and
(4) information obtained by fieldworkers. (36) Manageability (**).--Source: Field observation.
(36') Management problem description.--Source: Field observation. The problem and the probable effort needed to correct or contain the
problem were described. (See Appendix 12.)
(37) Preservation status (*).--Source: Discussion with owner or custo-
dian, or other means.
(37') Attitude of owner or custodtan toward preservatton.--Source: Dis-
cussion with owner or custodian, or other means.
(38) Threats (x).--Source: Discussion with owner or custodian, or other
means.
(39) Diseusston of preservation values.--This is a brief, nontechnical
description of the area's important natural values. (39') Addittonal notes
(40) Species lists (*).--This is a record of the kinds of species lists that were compiled for the area. The actual species lists are not
computerized. (41) Sampling forms (*).--Same as item 40.
(41') Other matertals.--Other materials such as significant feature forms
were noted.
(42) Publications («*).--This item was labeled Ziterature citations on the
Main Data Form.
Four other items were collected for each natural area, but it was
not necessary to record the information on the Main Data Form:
56
Governor's Region (*) Regional planning commission (*) Forest preserve district («)
Conservation district (*)
Because the boundaries of these regions coincide with boundaries of coun- ties or groups of counties, the computer was programmed to retrieve the item by comparing the natural area's county with the proper value or de- scription for the above items. Zoning information was not computerized for the natural areas, but a partial set of county zoning maps was assem-
bled for reference.
Natural Area Files and Maps
Each natural area has a file consisting of a computer printout, Main Data Form, and boundary maps. Other materials include species lists, vegetation sampling forms, aerial photos with overlays, unpub-
lished reports, and photos.
The natural areas were plotted on highway maps of each county, at a scale of 1 inch equals 2 miles. This set of maps was developed because they show at a glance the location of natural areas in each county. All natural areas were also marked with colored pins on a large-scale map of
Pianos.
PART IV SURVEYS
The purposes, procedures, and results of the various surveys are described in the following pages. Each kind of signifi- cant feature, from Category I through Category VII, was in- ventoried as a separate survey, but the surveys of different
categories often were conducted concurrently.
58
A few dozen of these
A bald cypress along the Cache River. anetent trees survive in the swamps of extreme southern Illinois.
Plate 6.
59
Section 14.
CATEGORY I SURVEY MAIN SURVEY
Summary
The Main Survey was a search to find areas with relatively undis- turbed natural communities, except for (1) prairies and savannas along railroads and in cemeteries, which were inventoried in separate Category I surveys, and (2) lakes and streams, which were included in the Category
VII survey.
Although the Main Survey for Category I significant features was the largest effort of the Inventory, it is not detailed at this point because the standard techniques of compiling available information, examining maps and aerial photos, aerial surveys, and ground surveys are detailed in Part III and in appendices. The results of the entire Category I sur-
vey are summarized in Part V.
Special procedures were involved in surveying cemeteries and rail- roads, so these surveys were separate from the Main Survey and they are
discussed in some detail in the following two sections.
60
Section 15.
CATEGORY I SURVEY RAILROAD PRAIRIES
Summary
A systematic survey was conducted to find prairie remnants along railroads. An aerial survey, followed by brief checks on the ground, was conducted in the fall and early winter of 1975. The most significant prairie remnants were revisited to complete the final evaluations and de- scriptions in the summer of 1976. Sixty areas with a total of 123 acres of high to very high quality prairie communities were included in the
inventory.
Introduction
Prairie remnants occur on railroad rights-of-way because many rail- roads were built before the prairies were cultivated. Prairies have persisted along railroads in the occasional places where they have es- caped heavy disturbance during construction and maintenance of the tracks. Factors that have favored the persistence of prairie vegetation include (1) burning and mowing of the right-of-way to reduce woody in- vasion, (2) a great distance from any source of seeds from trees and shrubs, and (3) dry embankments and wet depressions, which favor native vegetation over exotics. Although prairie plants grow along nearly every mile of railroad that crosses a prairie region, prairie of the highest natural quality is on land that has been least disturbed by construction
and maintenance of the railroad.
A large amount of literature demonstrates the importance of these remnants along railroads for scientific research and nature preserves. The value of remnant prairies along railroads was recognized by early plant ecologists such as Shimek (1925) in Iowa and Pepoon (1915, 1916, 1927b, 1928) and Vestal (1918) in Illinois. Botanists in Wisconsin have relied on railroad prairies for many studies; examples are by Gould (1941), Thomson (1940), Curtis and Greene (1949), and Wilson (1978).
61
Zoologists in Illinois also have frequently used railroad rights-of-way: examples of invertebrate studies are by Adams (1915) and Rapp (1946). Examples of vertebrate studies are by Hankinson (1915, 1917), Shackle- ford (1929), Koestner (1941), Goodnight and Koestner (1942), Long (1968), and Stupka, et al. (1972). Soil scientists use railroad prairies to study undisturbed soil profiles (see Douglas, et al., 1967). Prairie remants are valuable natural preserves in other states as well, as is shown by articles and abstracts by Betz (1978) for Indiana; by Scharrer (1972), Thompson (1972), Kohring (1978), and Chapman and Pleznac (1978) for Michigan; and by Ramey (1978), Troutman (1978), and King (1978) for Ohio. Because of their value in Illinois, Vestal (1931) and Miller (1943)
urged preservation of railroad prairies; Evers (1963), and Evers and Page (1977) described the natural values of railroad prairie remnants.
Procedure
The survey had four stages: (1) preparation for the field survey, (2) an aerial survey to find potential prairies, (3) an initial ground survey to determine the significant sites, and (4) a final field survey to describe and evaluate the significant prairies in detail. The first three stages were completed in the fall and early winter of 1975, and the
final survey was conducted in the summer of 1976.
Preparation for the field survey
Preparation consisted of (1) learning and refining survey procedures, (2) compiling available information about railroad prairies, and (3) examining maps and aerial photos to determine which railroads have
potential for prairie remnants.
Pilot study and training session.--As part of the contract proposal, a 70-page plan for surveying railroad prairies was written. Later, during the earliest stages of the project, more railroad prairies were visited and people were contacted to (1) refine the estimates of the size of the survey, (2) learn more about evaluating prairies, and (3) further test and develop survey techniques. The staff ecologists participated in a
6-day training session that included instructions in an airplane and on
62
the ground, fieldwork as individuals and in teams, and discussions and
reviews of techniques.
Compiling avatlable tnformatton.--Reports from the Illinois Depart- ment of Conservation, Natural History Survey, and Nature Preserves Com- mission were the main sources of existing information. The information consisted of locations and brief descriptions of stands of prairie vege- tation along railroads, and it was used to choose sites for testing the
survey procedures.
Examining maps and aertal photos.--Various maps and aerial photos were used to decide which railroads should be surveyed. A discussion of the factors that affect the potential for significant railroad prairies
is in Appendix 23. Briefly, the stages were as follows:
(1) A series of railroad maps was examined to find lines that were built so recently that the prairie would have been destroyed before the tracks were laid. Railroads built after 1891 were not selected for surveying unless they were on sandy or wet soil. Relatively few railroads were eliminated in this manner because the great majority
were built by 1891.
(2) Railroads were eliminated if they followed forested floodplains or crossed wooded hills. A presettlement vegetation atlas (Appendix
19) was used in this stage.
(3) Examination of topographic maps and aerial photos revealed that some rights-of-way were so narrow that they could accommodate only the railroad roadbed, embankments, and ditches. These lines, which
have hardly any undisturbed soil, were not surveyed.
The product of this stage was a set of county maps and a state map with the railroads color-coded to show their potential for prairie rem- nants. Of the 11,000 miles of railroad track outside of urban areas,
7,000 miles needed to be flown.
Aertal survey The aerial survey was conducted in the fall, when the prairie
grasses are brightly colored and highly visible from the air. Surveying
63
from an airplane during the growing season is not effective because prairie cannot be distinguished from weeds and naturalized grasses when
the vegetation is green.
Before each flight, a flight plan was drawn on a 1:500,000 scale map of Illinois and on larger-scale (2 miles per inch) county highway maps. The rights-of-way were viewed from a Cessna 172 at 500 to 800 feet above the ground, and a few hundred feet horizontally from the tracks, at anywhere from 70 to 120 miles per hour depending on the amount of prairie. Potential prairies were marked on county highway maps, and observations were recorded on tape during the flight. Since most tracks are paralleled by utility poles, a typical observation would be, "Dense stand of big bluestem on south side of tracks in section 23, beginning four poles east of blacktop and extending 13 poles farther east.'' For some lengths of right-of-way, the only observation might be, "Right-of-way consists of brushy and weedy embankments with occasional clumps of prairie grass.'"' After the flight, the tape-recorded observa- tions were transcribed onto the aerial survey section of a preliminary
data form.
Selection standards were kept relatively low to avoid overlooking Significant sites. At first the fieldworkers were overly cautious and selected sites that later would have appeared obviously too small or degraded. A total of 667 potential prairies were selected during the
aerial survey.
Intttal ground survey
The sites selected during the aerial survey were given an initial ground survey during the fall and winter to briefly determine the natu- ral quality and characteristics of each area and to select the least disturbed remnants for detailed description and evaluation during the next summer. Degree of disturbance was the basis for evaluating the prairies. The most prominent indicators of disturbance of a railroad
prairie are the soil and the vegetation.
Sotl.--Disturbance to the soil is the major reason prairies have
been destroyed or degraded. The soil on rights-of-way has generally
64
been disturbed by (1) construction of cuts and fills to make an even grade for the roadbed, (2) ditching, (3) grading to remove brush and smooth the surface contours, (4) bulldozing to repair the roadbed, (5) excavations to obtain fill for the trackway or road crossings, (6) spreading of cinders and ballast, (7) service roads, (8) cultivation, (9) local disturbances such as derailments, and (10) changes in
drainage patterns. Soil disturbances were detected and evaluated by
(1) looking for unnatural surface contours such as ridges and depres- sions paralleling the tracks and abrupt changes in the surface contours, (2) studying soil profiles, and (3) examining the species composition of
the vegetation.
Vegetation.--This is one of the most complex and variable features of a prairie. The following features were noted when evaluating the species composition: (1) presence of characteristic prairie species, (2) presence of rare species with narrow ecological tolerances, which cannot tolerate disturbance, (3) presence and relative abundance of
species that increase with disturbance, and (4) diversity of species.
Natural quality.--This measure of the degree of disturbance is dis- cussed in more detail in Appendix 22. In relation to railroad prairies,
the grading system was used with the following guidelines:
Grade A: Natural pratrte.--Species composition is natural or nearly so, with a full diversity of forbs and without an over- abundance of weedy species. Soil is undisturbed by earthmoving; or it may have been lightly disturbed but the vegetation appears
natural.
Grade B: Dtsturbed prairie.--Species composition is altered from the original natural condition. Some characteristic prairie plants are absent; others are overly abundant. There may be patches of native weeds and many exotic species. Soil is typical-
ly lightly graded or otherwise disturbed.
Grade C: Degraded pratrie.--Species composition is unnatural. There may be only scattered clumps and irregular, discontinuous
patches of grass, with a dominance of weedy vegetation.
65
Grade D.--Occasional prairie plants grow on soil that is either
disturbed or undisturbed.
Grade E.--Prairie plants are essentially absent because of distur-
bance.
Preliminary data collectton.--Each of the sites visited was brief- ly described on a preliminary data form. The significant sites were described in more detail with an initial ground survey form, species checklists, and a sketch map. The initial ground survey form provided a means for recording (1) basic information such as the location of the prairie, (2) descriptions of the natural features, and (3) evaluations of the natural quality and preservation values of the prairie. Check- lists allowed notation of the presence and relative abundance of prairie plants, and sketch maps showed the general location, size, boundaries, and characteristics of the sites. The procedures for the
initial ground survey are described in a report listed in Appendix 33.
Final field survey
Forty of the 104 prairies that passed the initial ground survey were found to not qualify as natural areas during the final field sur- vey because they had low diversity. This relatively high percentage of areas was eliminated because the staff was conservative while learning during the previous fall and winter, thinking that too many prairie species might be overlooked in the dormant season. In the following summer the staff learned that it would have been possible to adequate- ly judge a prairie's relative diversity in the winter, because the prairie remnants that appeared to have low diversity in the winter ac-
tually did prove to lack many species when revisited in the summer.
Results
Of the 64 prairies that were not eliminated during the final field survey because of past disturbances, 60 were designated as natural areas; four had been plowed or bulldozed since they were visited the
previous autumn.
66
Natural areas
The 60 railroad prairies have 40.25 acres of Grade A and 82.45 acres of Grade B land in 11 natural communities: dry prairie, dry-mesic prairie, mesic prairie, wet-mesic prairie, wet prairie, dry sand prairie, dry-mesic sand prairie, mesic sand prairie, wet-mesic sand prairie, wet sand prairie, and dry gravel prairie. The railroad prairies are in 29 counties, along tracks owned by nine different companies. The railroad
prairies are the only natural black-soil prairie remnants in 12 counties.
Disturbances
Since such small remnants were found along the railroads, a dis- cussion of the disturbances that have nearly eliminated the natural areas is pertinent. The major disturbances to railroad prairies have been grading of the soil during construction and maintenance of the tracks, cultivation, and herbicide spraying. Rights-of-way are usually only wide enough to accommodate the roadbed, embankments, and ditches; if the right-of-way is wider, then the extra land has usually been graded, which removes the topsoil and encourages weeds. If ungraded land has been left so that it could have supported prairie, it is al- most invariably cultivated. Prairie plants often grow on the most dis- turbed soil, where the land is too roughly graded to cultivate, or on excavations, dry cuts, and unnaturally wet areas where the native spe- cies can compete successfully with exotic plants. The third major disturbance, herbicide spraying, has recently damaged many prairies by either killing the native cover so that it is replaced by weeds or by
eliminating the forbs and leaving only grasses.
67
Section 16.
CATEGORY I SURVEY CEMETERY PRAIRIES AND SAVANNAS
Summary
This section discusses the procedures and results of a survey to find remnants of prairie and savanna vegetation in Illinois cemeteries. The survey, conducted from August to October 1976, relied heavily on volunteer help and previous surveys. Information was compiled for 3,923 cemeteries. Twenty-four sites were listed as natural areas be- cause of their relatively undisturbed vegetation and soil, and 111 other
cemeteries have native vegetation with potential for recovery.
Introduction
Settlers of the Illinois prairie established cemeteries on land that had never been plowed or intensively grazed. Some of these early graveyards support native prairie and savanna vegetation in parts that have not been mowed frequently. Other cemeteries have savanna vegeta- tion because they are mowed or burned often enough to suppress woody plant succession, but they have not been so closely manicured that the
Native forbs have been replaced by other species.
Dr. Robert F. Betz has pioneered in finding, preserving, and study- ing prairie remnants in cemeteries. He advised the project and contrib- uted knowledge gained from visiting over 800 cemeteries in northern
Illinois.
A few papers have been prepared about cemetery prairies in I1li- nois to stimulate interest in preservation of the remnants. These include articles and abstracts by Betz (1972, 1976), Betz and Lamp (1973), the Illinois Nature Preserves Commission (1977), and Keller
(1978).
68
Procedure
Procedures were developed for the cemetery survey in a 3l-page plan that was part of the contract proposal. Instructions to the fieldwork- ers are in two reports listed in Appendix 33. The basic stages of the
survey are discussed below.
Office preparatton
Preparation consisted of (1) finding cemeteries on maps and from other sources such as genealogists, and (2) deciding which ones should be checked in the field. All topographic maps and county highway maps for the state were reviewed, except for nine counties that had no prai- rie at the time of settlement. Both kinds of maps were checked because each kind had cemeteries that the other omitted. The Presettlement Vegetatton Atlas (Appendix 19) and soil maps were used to decide which cemeteries had potential for prairie or savanna remnants. The result was a set of county highway maps with cemeteries color-coded to indi-
cate which were to be field checked.
The staff attempted to reduce the number of cemeteries to be sur- veyed by learning which ones were established after 1900, when almost all upland prairie would have been farmed. Use of the following sources was explored: old atlases, State agencies, genealogical soci- eties, historical societies, libraries, church organizations, morti- cians' organizations, and cemetery associations. These approaches were not productive because most cemeteries were established well before 1900, and the sources did not have exactly the information needed (Ap-
pendix 24).
Pilot survey A staff member and a volunteer surveyed 73 cemeteries in four counties to test and develop the survey methods. Suggestions to volun-
teers on equipment and procedures were based on this survey.
Volunteer survey Individuals volunteered to do a county or counties, and the basic requirement was that one volunteer per team be able to identify prairie
plants. The volunteers were given county highway maps with cemeteries
69
marked to show which ones needed to be checked, and they were given forms and instructions. The fieldworker did the following: (1) record- ed basic information such as the date and name of the investigator, (2) visited each cemetery and assigned it a number on the map and form, (3) noted whether the cemetery was on prairie, forest, or transitional soil, (4) made a list of prairie plants in the cemetery, (5) gave an opinion about whether the cemetery was a nonqualtfying area, notable area, mar- ginal area, or natural area, and (6) recorded any other pertinent obser-
vations.
Staff survey
The species lists that were completed by volunteers were studied by the staff, and a ranking system for prairie plants was used to help decide which cemeteries should be revisited. The prairie plants were
placed in five groups:
I. Weedy native plants, often present in prairies because of distur- bance, and common or abundant in non-prairie habitats. Examples:
Whorled milkweed, frost aster, tall boneset, and tall goldenrod.
II. Typical prairie plants that can withstand heavy disturbance or readily invade disturbed sites. Examples: Big bluestem, Cana-
dian tick-trefoil, big-toothed sunflower, and pasture rose.
III. Typical prairie plants, often eliminated by heavy disturbance, but not by light to moderate disturbance. Examples: Pale coneflower,
downy sunflower, rosinweed, and Culver's root.
IV. Prairie species similar to Group JII, but less likely to invade disturbed areas. Examples: White wild indigo, prairie willow,
and compass plant.
V. Conservative prairie species, usually indicating lack of distur- bance. Examples: Lead plant, cream wild indigo, wood lily, and
white prairie clover.
The cemeteries were scored with a point system according to the number and kind of species present. Group I and II plants scored one point, Group III plants were given three points, and Group IV and V
plants received five points. As a general guideline, cemeteries with
70
about 40 or more points were rechecked by the staff, although the volun- teer's description of the cemetery's potential as a prairie preserve and
the degree of confidence in the volunteer's work were also considered.
The staff noted whether the cemetery was: (1) a natural area; (2) a notable area with (a) high, (b) medium, or (c) low potential for re- covery with management; or (3) a nonqualifying area. A brief form was completed for each cemetery visited, and the natural savanna or prairie
remnants were surveyed with the standard Inventory forms and procedures.
Results
Natural areas
Twenty-four cemeteries were judged to have significant natural areas. These areas total 14.8 acres of Grade A and 26.6 acres of Grade B communities. Eight communities are represented: mesic prairie, dry- mesic prairie, dry-mesic sand prairie, loess hill prairie, glacial drift hill prairie, dry-mesic savanna, and dry sand savanna. The cemeteries contain the only black-soil prairie remnants in seven counties and the
only dry-mesic savanna natural areas in Illinois.
Notable areas
One hundred and eleven notable areas of disturbed prairie or savanna, valuable for teaching or research, were identified. Thirty-five of these areas have high potential for recovery to high natural quality, probably with 5 years or less of management. Although it often is necessary to study the vegetation with several visits throughout the growing season to determine a remnant's potential for recovery, 33 cemeteries were tenta- tively classified as having medium potential and 43 cemeteries as having low potential for recovery with management. Work by Dr. Betz and others has shown that some mowed cemeteries do not show their true potential for
recovery until they have been protected and managed for a few years.
a
Section 17.
CATEGORY II SURVEY HABITATS WITH RARE, THREATENED, AND ENDANGERED SPECIES
Definitions and Procedures
Introductton
The Category II survey included vertebrate animals and vascular plants that are rare, threatened, or endangered in Illinois. The term endangered is used in the following discussion as a general adjective, equivalent to rare, threatened, or endangered, unless the context of the
discussion dictates otherwise.
People and organizations involved with endangered spectes
Many people and groups have studied, protected, and compiled lists of endangered species and their habitats in Illinois. The Illinois Endangered Species Protection Board is the official State agency con- cerned with endangered species. The Illinois Department of Conservation administers the Endangered Species Protection Act, protects certain en- dangered animals through fish and game laws, and manages some areas to maintain endangered species. The Illinois Nature Preserves Commission is involved with the acquisition and protection of habitats with endangered species and has been involved with determining the status of endangered animals and plants. The Illinois Natural History Survey has contributed much work and knowledge toward development of endangered species lists and conducts research and management work on endangered species. The Illinois State Museum has compiled information about endangered species and has contributed this knowledge to help determine the population sta- tus of Illinois' native flora and fauna. The Illinois Department of Transportation has published a summary of endangered species records, and the U. S. Forest Service has funded studies in the Shawnee National For- est. Many people have conducted research and contributed knowledge as individuals or as members of various museums, environmental organizations,
and academic institutions.
72
The Natural Land Institute received a grant in 1977 from the Joyce Foundation to conduct a year-long Endangered Species Project. The pur- pose of the project was to compile information on the distribution, pop- ulation status, and habitats of vertebrate animals and vascular plants that are rare, threatened, or endangered in Illinois. With contributions from specialists, the Endangered Species Project is preparing a publica- tion that will cover the above points and make recommendations for pro-
tection and management of species.
The Natural Areas Inventory and the Endangered Species Project shared the tasks of compiling information from museum and herbarium searches, reviewing research files and literature, field surveying, and interviewing biologists. The Inventory concentrated its efforts on iden- tifying and describing specific sites for endangered species, and the Endangered Species Project was oriented toward determining the population status and management needs of endangered species. Consequently, the Endangered Species Project took the major responsibility for compiling distribution records and making a preliminary determination of each spe-
cies' population status, and the Inventory concentrated on fieldwork.
Determining the status of spectes
The Inventory and the Endangered Species Project had the benefit of various endangered species publications and preliminary lists contributed by many cooperating individuals and agencies. The Inventory hosted a series of workshops conducted by the Endangered Species Project, at which specialists discussed fishes, amphibians and reptiles, birds, mammals, and vascular plants. Interim lists prepared by the Nature Preserves Com- mission and Department of Conservation served as the bases for discus- sions. For animals, the workshop participants designated each species as either: (1) recommended for state endangered status, (2) recommended for state threatened status, (3) assigned to rare, restricted, uncertain, or exploited status, or (4) deleted from the list because the species is either too common, probably extirpated, or of questionable occurrence in Illinois. Because of the large number of plants considered (about 500) the designations by the botany workshop were more general, and more
effort was spent simply adding or deleting species. The status of each
73
species was determined by using the criteria outlined in Appendix 25 as guidelines, but in practice the workshop participants usually reached a consensus without lengthy analysis. This screening process was a practi-
cal and expedient way to prepare for further work.
As a result of the workshops, the Natural Land Institute's Endan- gered Species Project submitted to the Endangered Species Protection Board a list of plants and animals recommended for official designation as endangered and threatened species in Illinois. The Board invited com- ments from the public on its own preliminary list, and in December 1977, the Department of Conservation issued an administrative order listing the vertebrate species adopted by the Endangered Species Protection Board as endangered and threatened in Illinois. The Board adopted the following
definitions:
Federally endangered spectes.--Any species which is in danger of ex-
tinction throughout all or a significant portion of its range.
Federally threatened specites.--Any species which is likely to become an endangered species within the foreseeable future throughout all
or a significant portion of its range.
State endangered spectes.--Any species which is in danger of extinc-
tion as a breeding species in Illinois.
State threatened species.--Any breeding species which is likely to become a state endangered species within the foreseeable future in
BET n07S .
Significant features and exceptional features
When the Inventory began its survey for endangered species, a final list of endangered species based on sound information was not available. The Inventory did not attempt to make a final determination of each spe- cies' status, but used the concept of stgntficant features and exception- al features instead of the terms endangered and threatened. Significant feature status was limited to species so rare in Illinois that they merit special preservation efforts. If a species was given significant feature status, then every known occurrence of the species in Illinois was a
Category II natural area.
74
A plant species was considered a significant feature if currently known from three or fewer sites in Illinois. A plant would qualify as a Significant feature if known from five or fewer stations on a vulnerable site such as a wetland, prairie, or mineable mineral. Exceptional fea- ture status was given to any plant species that was too common to qualify as a Significant feature, but was rare enough to add exceptional value to an area. Because the Inventory lacked comprehensive knowledge about the relative abundance of these less-threatened species, an upper limit was not set for the number of sites from which a plant could be known and still be considered an exceptional feature. However, a plant usually was
not listed as an exceptional feature if known from more than 15 sites.
Animals were treated in a manner similar to plants, but species were not as readily assigned significant feature status. Most animals are mo- bile or secretive, so their numbers and distribution are not determined as readily as for plants. For example, several birds are listed as en- dangered by the Endangered Species Protection Board but few natural areas were included as habitat for endangered birds, for two reasons: (1) Par- ticularly for birds of prey, rarely could sites be identified where the species nests reliably from year to year. (2) In the case of marsh birds and waterfowl, the staff sometimes had reports of 10 to 15 possible nest- ing sites, but none was listed as a significant feature because the best breeding sites could not be determined. Most likely many of these secre- tive wetland inhabitants are more common than is readily apparent, and the Inventory could not confidently choose the sites most critical for
the species' survival in Illinois.
Although large areas were recognized for the river otter and greater prairie chicken, another problem is illustrated by the bobcat, which ranges so widely that it was not possible to identify specific areas as critical habitat. Fishes known only from Lake Michigan or from a few collections in the Mississippi or Illinois rivers were not listed in the
inventory.
During the endangered species workshops, the terms rare, restricted, or uncertain status were assigned to some species that appeared on ear-
lier preliminary lists. The term rare was used in reference to species
75
that have low population levels but are not threatened or endangered with extirpation. Restricted status was assigned to species with very limited ranges in Illinois. Uncertain status was given to species for which in- sufficient information was available regarding population status. These terms are not used or defined in Illinois or Federal endangered species laws. Species in these categories were usually treated as exceptional
features.
Inventory procedures for animals
The project relied largely on information from other people and agencies to identify habitats with endangered vertebrates. Gathering this information was a joint effort between the Inventory and the En- dangered Species Project. The main sources of locality records are de-
scribed in the following paragraphs.
Fishes.--The project relied on the computerized records of the I1li- nois Natural History Survey, which has data from its own long-standing
collections as well as records of collections made by other investigators.
Amphtbtans and reptiles.--The Natural History Survey compiled rec- ords of endangered amphibians and reptiles for the Endangered Species Project. The work involved gathering collection data from scientific
organizations and herpetologists throughout the state.
Birds.--A wealth of information was available from amateur birders, the Department of Conservation, Natural History Survey, other profession-
al ornithologists, and the literature.
Mammals.--Information from published sources and museum collections was used, but most knowledge of the current populations of endangered mammals came from fur trappers, wildlife biologists, and mammalogists at universities. The project sought information about bobcats, swamp rab- bits, and other conspicuous mammals by distributing questionnaires to hunters at deer check stations, but the information gained in this manner
was of little value.
Field searches.--Although special surveys to find new populations
of endangered vertebrates were not a part of the inventory project, the
staff did some fieldwork to verify reports of endangered animals and
76
searched for these species during other field surveys. The project pro- vided travel expenses for volunteers who checked specific sites and searched for certain species. Returns from these efforts were minimal, because surveys for vertebrates require more time and persistent effort
than was exerted.
Inventory procedures for plants
The main sources of plant locations were herbaria, literature, per- sonal knowledge of botanists, and files of various agencies. The Endan- gered Species Project took responsibility for organizing this information, and the Inventory helped gather the records. The Endangered Species Project compiled lists of sites for each county, giving the pertinent collection data for each species. The Inventory staff chose sites from these lists with recent and precise enough locality data that there was some promise that the plant could be relocated. The collector was con- tacted when possible and necessary in an attempt to get current informa- tion and directions to the site. The effort expended in the field depended on how promising a site appeared once it was visited: some Sites had been destroyed and other sites offered no clues about specific areas in which to concentrate the search. Between five and 20 sites were
visited in a typical day.
Some sites were not visited, if enough current information was available about the species' population, location, and habitat. About 18% of the Category II plant significant features were found because of fieldwork unsupported by past collection records or observations. These were either species found by specially searching suitable habitats or species found during the Category I and III surveys. Appendix 26 details some of the survey procedures and relates some experiences that might
help other endangered plant surveys.
Results
The animals and plants are listed in Appendix 3, with the following information for each species: (1) status according to the Endangered Species Protection Board (for animals), (2) status recommended by the
Natural Land Institute's Endangered Species Project (for plants), (3)
i ar,
+ das
.
77
number of sites identified as significant features, and (4) number of
sites identified as exceptional features.
Number of stgnificant features and excepttonal features The number of significant feature (SF) and exceptional feature (EF)
occurrences in natural areas are as follows:
SF's EF's CTS Ves Se ee ee ee 7 44 Amphibians and reptiles. .... 18 67 a SE a eee A 145 LE ea ee eee ee 25 Waseca planes. ose. o. ss 0 oy 2, 462 629
Habitats and distribution
Endangered animals and plants occur in a wide variety of habitats throughout the state, but the greatest numbers are in wetlands in extreme northeastern and southern Illinois (Figure 2). Wetland and prairie spe-
cies are most often endangered because the habitat is endangered.
Endangered plants were most often found in high to very high quality Natural communities, as shown by the number of significant features in
each natural quality grade:
Grade A: 146 Grade B: 114 Grade C: 161 Grade D: 25 Grade E: 16
Twenty-five of the Grade A habitats are cliffs and bluffs, but most are prairies and wetlands. Many endangered plants require early successional communities, but they are usually in naturally disturbed areas or primary successional communities rather than artificially disturbed sites. A few endangered plants were found in artificial sites, especially ponds and ditches.
Endangered animals appear to be more tolerant of disturbances, as shown by this tabulation of significant and exceptional feature occurren-
ces:
78
Grade A: 3 Grade B: 6 Grade C: 34 Grades Dae! Grade E: 5
Part of the reason that more animals are in disturbed communities is that many species are mobile and require rather large territories, and the only sizeable habitat remaining for them has been disturbed by hu- mans. The most extreme example of an artificial habitat is an abandoned underground limestone mine that has the only known hibernating colony of
the endangered Indiana bat in Illinois.
Newly discovered spectes
Three aquatic plants were discovered for the first time in Illinois. Other plants that had not been seen in Illinois in many decades were re- located, and some species thought to be endangered were found in so many localities that they were deleted from the tentative endangered species
liplisyee
Prior to the inventory, the red squirrel was thought to have been extirpated from Illinois by the early 1900's. The red squirrel is a small animal of northern forests, unlike its larger, reddish relative, the fox squirrel, which is common throughout the state. Although the red squirrel had not been listed as part of the current Illinois fauna, the
staff found red squirrels in four northern Illinois counties in 1977.
79
Section 18.
CATEGORY III SURVEY HABITATS WITH RELICT SPECIES
Definition
Category III significant features are habitats with relict species. A relict species is one that occurs in a small, disjunct population that is a survivor of a formerly more widespread population. The range of the relict species has disintegrated or retreated because of climatic changes, and the species remains in a local, specialized habitat that provides a suitable microclimate and allows it to survive competition
from other species.
An operating definition of a relict habitat--exactly what to include in the inventory--required much study and discussion by the Inventory staff. Theories of the geographic origins and climatic changes that have affected the modern flora were debated. There were sometimes questions about whether a colony was an outlier of an expanding population or a relict of a contracting population. Some small, scattered populations might be relicts or they might be the result of a lack of suitable habi-
tat at the edge of a species' range.
The following guidelines were established: (1) A plant should be disjunct by at least 100 miles from its normal range. (2) Assemblages of more than one relict species, rather than sites with single species, were considered. (3) An open-ended list of possible relict or disjunct spe- cies was made, and two or more of these species had to be present on the same site because of approximately the same unusual habitat requirements in order for the site to be a relict habitat. Although animals, especial- ly invertebrates, are sometimes part of relict associations, analysis was
limited to plants.
Procedure
The Category III survey used the same techniques of compiling back-
ground information, contacting people, examining maps and aerial photos,
80
aerial surveys, and ground surveys as for the Category I survey. These survey stages were usually conducted at the same time as the search for Category I and II significant features. The survey was a search for hab- itats rather than individual species, so sites with unusual soil and topography that were known in general to have relict species were sur- veyed. These habitats include seeps, sand areas, moist cliffs, and ravines and bluffs along Lake Michigan. Some other communities, such as hill prairies, might be considered relict habitats, but they were simply
considered as part of the Category I survey.
Not all of the thousands of cliffs and seeps in Illinois could be searched for relict plants, and such a detailed search was not necessary because only the largest seeps and shaded cliffs are likely to maintain an adequate habitat for relicts. For example, the smaller bedrock out- crops are more likely to have been periodically covered by soil; also, they have relatively little effect on the microclimate and provide little area for colonization. Similarly, small seeps are likely to go dry periodi- cally or to lose species through local extinction. The approach was to check the largest first; if these largest sites had relicts, then smaller sites were visited. It was found that relict assemblages were nearly all
restricted to the largest and most extreme sites.
Results
Thirty-nine sites with a total of 45 Category III significant fea- tures were listed. Twenty-five sites are cliff habitats, six are on bluffs or in associated ravines, five are seeps, and three are in sand
prairie or barren communities.
In northern Illinois, the relict sites are on cliffs, in seeps, or along the Lake Michigan bluffs. The most common relicts are white pine, Canada yew, and sullivantia. There were a few relict sites in sand areas and seeps in central Illinois, but no relict species can be named as par- ticularly frequent in these communities. In southern Illinois, the rel- ict assemblages occur on moist, shaded sandstone cliffs and in seeps. Cinnamon fern, hay-scented fern, clubmosses, and sphagnum moss are the
most frequent relicts, but about 12 other species are relict associates.
8]
Section 19.
CATEGORY IV SURVEY GEOLOGIC AREAS
Definition and Procedure
Category IV significant features are outstanding representatives of the state's geologic diversity. This category includes areas that are outstanding because of stratigraphy and sedimentation, igneous rocks, geologic structures, topographic features, and fossil localities. Geo- logic areas differ from other categories of natural areas in the follow-
ing respects:
(1) Geologic features are in general not threatened because they are
usually large, numerous, and not vulnerable to destruction.
(2) Many significant geologic features extend over large regions, and it is not always easy to designate a small site to represent a large-
scale feature.
(3) Human disturbances such as roadcuts and mines are often important advantages to geologists, because the disturbances provide fresh
rock exposures for study.
Because of the above factors, geologic areas were inventoried in a dif- ferent manner. Unlike ecological areas, where the goal was to list every occurrence of a particular significant feature, only representative sites were chosen for geologic areas. Areas were selected to form a system
that, taken as a whole, represents the geologic diversity of the state.
The inventory of geologic areas was compiled by Dr. H. B. Willman of the Illinois State Geological Survey. In addition to the information re- corded for other kinds of natural areas, Dr. Willman described the nature of the exposure (streamcut, roadcut, etc.) and noted whether the site has
a type stratigraphic section.
Selecting geologic areas.--Because there were often several out- standing examples of the same geologic feature, preference was given to
areas with the following characteristics:
82
(1) Natural exposures (2) Sites with a variety of geologic features (3) Sites where preservation might be practical
(4) Sites with type geologic sections or published studies
Determining boundaries.--Boundaries were drawn to adequately repre- sent the significant feature. For example, in some cases a small section of a cliff was chosen even though the same rocks are exposed for a mile or more along the valley wall. Some sites were mapped somewhat larger than needed to make an adequate example because the precise location of the most significant exposure could not be determined without a field
examination.
Results
One hundred and sixty Category IV significant features were identi- fied. The following kinds of geologic features were represented (with the
number of significant features selected):
Stratigraphy and sedimentation. ... . 106 NeMeOUS TORS 5 5 6 6 6 00 0 oO oO 2 CSo@iloeae Sirius 6 so 5 6 6 & 5 6 oo 8 NGOpOAceyaine wWSZeHESS, 5 5 6b eb 6 oo oo OSS! WoOceltEIeS ¢ 6 5 oo 6 6 6 6 oe A
Of the 106 stratigraphic areas, 53 are natural exposures and 16 are part- ly natural. One hundred and twenty of the 143 geologic formations in
Illinois are in geologic areas. None of the geologic areas are in active quarries, pits, or mines, except for an outstanding crinoid locality that
is in the inactive part of an active quarry.
In listing geologic areas, many sites were considered and many dif- ficult choices were made. As a supplement to the sites listed as Category IV significant features, an annotated list of 119 major alternative sites
and 10 historically important geologic areas was compiled.
Section 20.
CATEGORY V SURVEY NATURAL STUDY AREAS
Definition
Natural study areas are sites managed and used as nature preserves
or natural areas for teaching and research. A site qualified as a natu-
ral study area if managed and used for natural science studies, even
though it might have been disturbed and lacked any other significant fea-
ture.
This category of natural area includes two groups: (1) areas
maintained and used by local groups and schools, and (2) areas protected
as nature preserves.
nize
(1)
(2)
(4)
Sehool natural areas.--The following guidelines were used to recog-
these areas:
Protectton.--If the area is owned by a school, then the school ad- ministration must have given the area some type of protected status. If the area is not owned by a school, then the school must have a lease or written agreement with the owner to maintain the tract as
a natural area.
Permanence.--The area must have at least a 3-year program of use. That is, the area must have been used for at least 5 years, or it must be committed to a 3-year program if it has recently been estab-
lished.
Use.--Research and education must be the main use of the area. Land that is primarily used for recreation or simply as a wildlife refuge does not qualify. Experimental areas (for example, mowed or plowed areas) do not qualify. A tract does not qualify if it has been set
aside but is not studied.
Natural quality.--The area must be relatively undisturbed, or it must have recovered from disturbance so that the vegetation is domi- nated by native species and is not in the earliest stages of second-
ary succession. In general, the area must have natural communities
84
that are Grade C or higher. However, abandoned fields may qualify if natural succession is being studied. Prairie restorations may
qualify as natural study areas.
Many areas used by schools did not fit well under these criteria, which is understandable because the schools did not establish areas under the Inventory's guidelines. The two most common problems were that the school set aside an area for nature study but never established exact boundaries, and that the area has other uses in addition to nature study. In such cases the boundaries were drawn for the inventory using the best available information to include only land that has nature study as its
main use.
Nature preserves.--The second group of natural study areas are sites that are specially protected as nature preserves or are part of a formal system of natural areas. This group includes Illinois Nature Preserves (Illinois Nature Preserves Commission, 1977), Federal Research Natural Areas (Federal Committee on Ecological Reserves, 1977), Registered Natu- ral Landmarks (Wieting, et al., 1977), Society of American Foresters’ natural areas (Buckman and Quintus, 1972), and lands held by The Nature Conservancy, the Natural Land Institute, and similar land preservation
organizations.
Procedure and Results
Elementary and secondary schools.--With help from the Illinois Office of Education, a questionnaire was sent to all 211 private second- ary schools and to all 1,030 public elementary and secondary school dis- tricts (representing 4,536 schools), asking whether they used an area for nature study. The schools were asked to return the questionnaire even if they did not use such an area. Of the 1,241 schools or dis- tricts surveyed, 642 (or 52%) replied, and 135 (or 11%) reported that they owned or used natural study areas. If a school responded positive- ly, a second questionnaire was sent, asking for more detailed informa- tion and asking for a map showing the boundaries of the area. Some of the positive responses were not included in the inventory, usually be-
cause the area did not meet the project's criteria or because the school
gave insufficient information about the area. As a supplement to the questionnaire survey, Donald Greene and Robert Walker generously shared the results of an unpublished 1976-77 survey of outdoor classrooms in Illinois by the Illinois Chapter of the Soil Conservation Society of America. The final number of sites listed because of the survey of ele-
mentary and secondary schools is 45 areas.
Colleges and untverstttes.--The 113 academic colleges and universi- ties that have biology or related curricula were surveyed in a manner similar to elementary and secondary schools, but the staff also relied on personal knowledge and contacts to supplement the mailed question- naire. Forty areas were listed as Category V areas because they are used or managed by colleges or universities. Some of these sites had been listed in a previous survey by the Illinois Board of Higher Educa- tion (1975).
\ Nonacademie organtzattons.--Forest preserve districts and conserva- tion districts were asked about land that the district specially main- tained as nature preserves or education areas. Thirteen of the 17 districts responded, with descriptions of 31 areas. The largest park districts were contacted, but the Inventory relied on the questionnaires that were sent to schools to learn about most park district areas. Other organizations involved in natural area preservation were contacted, such as the Natural Land Institute, The Nature Conservancy, the Parklands Foundation, and the Forest Park Foundation. Information was solicited in several statewide news releases and various newsletters, including a
mailing to all the soil and water conservation districts in the state.
As a result of the survey, 266 Category V significant features were listed in 251 areas, including 66 Illinois Nature Preserves, 16 Federal
Research Natural Areas, and nine Registered Natural Landmarks.
86
Section 21.
CATEGORY VI SURVEY UNIQUE NATURAL AREAS
Definition and Procedure
Some sites were recognized as natural areas because they have unique features: these are areas worthy of preservation efforts that do not fit well in the other natural area categories defined by the Department of
Conservation.
For example, two tracts were recognized because of their ancient bald cypresses and tupelos. The trees themselves--with their great age and their own plant and animal communities--are sufficient reason to pre- serve the swamps. (In both tracts with these trees, the swamps did ac- tually qualify as Category I significant features. Other significant features usually occur with Category VI features, and only five areas
were simply Category VI.)
Several caves were included as Category VI sites because of their outstanding invertebrate fauna. Otherwise, invertebrates were not used as Significant features because our knowledge of invertebrates was too limited to avoid making arbitrary choices about areas. However, compre- hensive knowledge about the invertebrate fauna of Illinois caves has been summarized by Peck and Lewis (1978); and after some more fieldwork, it was possible to confidently list the caves with the most outstanding
invertebrate faunas.
Another relatively large group of unique features includes sites with unusual assemblages of plants. These are unusual habitats with dis- junct species, but they do not qualify as Category III sites under the Inventory's definition. However, scientists agree that such sites are
valuable and should be listed in the inventory.
An area might be considered "unique" if it is the only undisturbed
example of a particular natural community, but such areas were included
87
in the regular Category I survey rather than considering them as Category
VI significant features.
Results
Thirty Category VI significant features were found in 29 areas.
They can be summarized as follows, with the number of occurrences in each group:
Pnrque’ ccologteal features . 2. ./5 5°. 49 Unique floral assemblages
Outstanding invertebrate cave faunas . . 13 Varge™batihabernacuilla’. 3). sy < - » « 4
Otherhunigquestaualvassemblages..as.". 2.435
88
Section 22.
CATEGORY VII SURVEY AQUATIC AREAS
Definition and Procedure
Aquatic areas include streams and lakes, which were not evaluated as part of the Category I survey. Vegetated ponds and natural wetland com- munities were evaluated by the Inventory staff and were included as Cate- gory I areas, but streams and lakes were inventoried as Category VII
features.
The Illinois Natural History Survey provided recommendations for listing outstanding streams and lakes, based on years of accumulated data and experience with the natural waters of the state. Smith (1971,
1973) and Evers and Page (1977) of the Natural History Survey summarized information about outstanding aquatic areas in Illinois and gave their
criteria for recognizing significant sites.
Dr. Philip W. Smith and Dr. Lawrence M. Page of the Illinois Natural History Survey compiled a list of candidates for outstanding natural aquatic areas. They listed 30 sites or groups of sites, almost all of
which were included as Category VII sites or in other categories.
Results
Seventeen areas with outstanding lakes or streams were included in the inventory. The five lake areas include Illinois Beach State Park and glacial lakes in Lake County, as well as backwater lakes along the Mississippi and Illinois rivers. The 12 stream segments, totaling about 210 miles, range from the Rock River and Apple River in northwestern Illinois to Big Creek and Lusk Creek in the southeastern corner of the state. However, large parts of the state, particularly western Illinois and (except for the Embarras River) south-central Illinois, have no Cate-
gory VII streams.
89
Section 23. LITERATURE SURVEY
John Whtte and Donna Evans
Purpose
A literature review was conducted to (1) find articles useful for developing survey procedures and classification systems, (2) learn about natural areas that were not previously known, and (3) compile a bibliog-
raphy of literature pertaining to sites listed by the Inventory.
The usefulness of the literature review proved to be as follows: (1) The survey of published works was an integral part of developing in- ventory techniques and classification systems. (2) Except for a few endangered species sites, no natural areas were identified solely as the result of the literature search: although many areas were cited in pub- lications, they were readily identified through other means. (3) Some publications provided information that was of immediate value to the In- ventory, but the bibliography should be more useful to future researchers than it was to the Inventory. The bibliography should help researchers choose sites and topics for further study. Scientific studies increase the preservation value of a natural area, and the studies themselves are
more valuable if they are done in areas that have had previous studies.
Procedure
The literature review required about 1,000 hours of searching, con-
ducted in the following stages.
Selecting the literature sources.--Periodicals were chosen that would give a high return of articles from a wide variety of disciplines.
About 25 journals were chosen for thorough review.
Revtewing the publicattons.--It usually was most efficient to scan the table of contents of each volume, looking for key subject words. Using the table of contents was almost always faster and more accurate
than using the subject index. Articles with promising titles in the
90
table of contents were searched for references to natural areas or other useful information. All articles about the ecology of Illinois or neigh- boring states were recorded. This method was more efficient and effec-
tive than using indices such as Biological Abstracts.
Computer search.--The computer services of the Library and Informa- tion Retrieval Research Laboratory at the University of Illinois was employed to find articles written after 1970. This computer retrieval service uses Biological Abstracts, Comprehensive Dissertation Abstracts, and Science Citation Index. Citations were retrieved by using a list of subjects (fauna, cave, glade, etc.) and a list of place names (Illinois, Iowa, Indiana, etc.); the computer retrieved articles with keywords that overlapped from both lists. This computer system had some shortcomings: (1) not all relevant keywords could be anticipated; (2) some keywords had more than one meaning, so irrelevant citations were retrieved; (3) many known articles were not retrieved, creating doubts about the completeness of the database and the effectiveness of the search; and (4) each promis- ing article had to be read individually instead of being read as part of the regular review of periodicals. The search service retrieved 2,152 citations; 56 pertained to natural areas, and all but 15 of these were
also found by the regular literature review.
Graduate theses.--Every academic unit that has a graduate degree program in biology, ecology, geology, or related subjects in Illinois was asked for a list of Master's and Ph.D. theses. Most departments did
not respond or reported that they had no such list.
Bibliographies and reference lists.--Several published bibliogra- phies were searched for references to natural areas. The most important general bibliographies for Illinois are by Vestal (1934), Isfort (1949), and Pemble, et al. (1975). The literature cited in many articles led to
new references.
Natural Area Bibliography
Summary The bibliography of Illinois natural areas covers 1,484 titles.
This includes 1,413 references to biology and ecology and 71 references
91
to geology. About half of the natural areas (527 out of 1,089) have pub- lished references. The 10 natural areas with more than 40 references are
as follows (with the number of citations for each):
Brewease, Woods’ (Champaneny Co. )hihwe “setae? nny 213 AlierGon Park (PitattCol). Saal sbee cb Mele ta haere. 164 Pine Hills--LaRue Swamp--Wolf Lake (Union Co.) ... . 143 PelamoasmBeache(LakerCon)). OPAC Gh). 2 On Gy . GAC, o.-N97 Browmstedd Woods «(Ghamparen Col )i.re*. v.78. Oe 2 2 8 879 Grane iGncyen(UnLon rand (Jackson tcoss))..%) BOLUS! PGs... 61 ServecmeRochkes (laSal Mes CO) a em Peel ccm ley ols, <sc0'S ia a dee, OD Horseshoe jake i(Aliexander (Gopi. s we fer us Heh sa ei eds hss. s,~ (Dl Heron Pond--Wildcat Bluff--Little Black Slough (Johnsong_COs)ycasesy oes ont score mele rvers on tend buske Creeks (PopeiCosdeya sitter! -e31e}34-neisevrasere 243
In addition to citations for areas listed by the Inventory, approximately 3,500 other references about field biology, ecology, and inventory tech- niques were compiled. About 1,700 of these pertain to Illinois, and about
1,300 refer to other Midwestern states.
References to geology
Relatively few references to geology were selected for the bibliog- raphy because they were included only for geologic areas. Although each geologic area might have an average of five or more important articles, usually one reference that cites previous publications was included. Geologic references were not compiled for all natural areas because lit- erature about Illinois geology through 1965 has been indexed in a bibli- ography by Willman, et al. (1968). This bibliography includes about 4,400 publications by the staff of the Illinois State Geological Survey, and it lists about 400 graduate theses.
References to btology and ecology The 1,413 references other than geology papers can be placed in the
following groups:
Detailed scienttfie references.--Describe a feature or features of one or more natural areas, giving detailed information about the site. Examples: Klimstra (1969), Lindsey (1962), and Park, et al.
92
GISSS) PS .-soSvartrclest
General sctentifie references.--Results of studies that relied on collections and observations in several sites, including one or more natural areas. Examples: Pepoon (1927a), Smith and Parmalee (1954), and Zetek (1918) . . . 430 articles.
Incidental sctenttfie references and brief notes.--Results of stud- ies that were based on observations or collections from a natural area, but that could probably have just as well been based on some other area; and brief notes about a feature in a natural area. Ex- amples: Hoffmeister and Grebner (1948), Lord (1959), Schanzle C875), and Zar (19608) 2s 74 cartulcles:
Preservation articles.--Promoting the preservation of areas, de- scribing preservation efforts, listing areas that are preserved, and
lamenting the destruction of areas . . . 113 articles.
Popular artteles.--Mostly about state parks. Examples: Malkovich (1962) and Mohlenbrock (1971) . . . 102 articles.
Publications relating to the use of areas.--Management and develop- ment plans, historical and archeological accounts, and visitor
guidebooks’+ 2?2-Sil@artielesr
Articles from newspapers and newsletters were included in the natural
areas bibliography only if they had important information not available
in other publications. Many important studies were excluded because the
authors mentioned no specific natural areas. Some studies, especially
old ones, were not included because the study area was not named or de-
scribed well enough to be identified.
Sources of publtcattons
The biology and ecology references came from the following sources
(with the number of references from each source):
Scientific: perioditalisms) Aces SiSlOepepers =.) ores Books, special publications, and reports .... 215
Newspapers, magazines, and periodicals of conservation’ eroups' 272) ete Lee te . eens
Master's theses2°%' 2 (9508 bE. > Ute 2” eee (eee
93
Phewendissertataonsia! gieisrili bee satatd seers 36
Other graduate student research papers ..... 10
The 774 articles in scientific periodicals came from 119 different series of periodicals. The following journals have the largest number and vari- ety of papers about the ecology or biology of natural areas: Transac- tions of the Illinots State Academy of Setence (with 237 articles), American Midland Naturalist (63 articles), Ecology, and Ecological Mono- graphs. Also, the Bulletins and Bitologtecal Notes of the Illinois Natural
History Survey have 38 articles that mention natural areas.
The most prolific sources of popular articles about natural areas are Illinois magazine (formerly Outdoor Illinois, with 78 articles), Illtnots Audubon Bulletin (75 articles), and Freld Museum of Natural His- tory Bulletin (17 articles).
Although a broad representation of disciplines was sought, there were more articles about botany than any other subject referring to spe- cific natural areas. Papers on the botany of natural areas are most common in Rhodora, Botanical Gazette, American Fern Journal, Castanea, Bryologist, and Mycologia. There are many studies about birds in Wilson Bulletin and Auk, and several natural areas are included in breeding-bird censuses and winter bird-population studies in Amertcan Birds and Audubon Field Notes. Other papers about vertebrate zoology are most often found in Journal of Wildlife Management, Herpetologica, and the Natural History Miscellanea of the Chicago Academy of Sciences. Most papers about inver- tebrate zoology in natural areas appear in the Transactions of the Amert-
ean Entomological Soctety and Illinots Natural History Survey Bulletin.
Dates of publications
Early descriptions by non-scientists.--The earliest descriptions of Illinois' natural landscape do not often have recognizable place names. Unless the site was described in detail or is a prominent landmark, it is rarely possible to identify specific natural areas in the earliest writings. French explorers described sites along major rivers; but other than the notes of the Federal land surveyors, the earliest refer- ence that was found is the journal of Colbee C. Benton, who visited
Indians in the Chain O'Lakes region in 1833. He described landmarks now
94
known as Cedar Lake, Grass Lake, and Elizabeth Lake (Angle and Getz, 1957). Beginning in the 1830's there were several booklets and articles in Eastern magazines that described the economic potential of the I1li- nois landscape. Examples include the booklet by the Illinois Central Rail-Road (1856) and others listed by McManis (1964), Poggi (1934), and Krohe (1978).
Early publicattons by naturaltsts.--The earliest known publication in which a naturalist described sites listed by the Inventory is a refer- ence to Bald Knob (Union Co.) and Equality Cave (Saline Co.) by Andrews (1860). There are earlier important publications, but they do not de- scribe specific natural areas. For example, Kennicott (1855, 1857) dis- cussed the animals of Illinois, and Short (1854) described the prairies. Engelmann (1863) described some natural communities of southern Illinois; and similar articles appeared in two series of books edited by A. H. Worthen, entitled the Geological Survey of Illinots and Economical Geol-
ogy of Illinots, beginning with the first volume by Worthen (1866).
Publtcations in thts century.--Sixteen articles about natural areas are known from the 1800's, but most are from this century. The Inventory found pertinent articles published in every year since 1901. Figure 1 shows the rapid increase in the literature about natural areas, which has coincided with the development of the science of ecology. The number of publications has roughly doubled every 20 years, apparently unaffected by economic conditions except for a decline during World War II. The rela- tively large number of publications listed for the last 20 years is in- fluenced by the current availability of special reports that will become scarce once they are out of print, but this hardly begins to account for the tremendous increase in natural areas literature beginning about 1960. Part of the increase can be attributed to the National Environmental Policy Act, which requires studies of the environmental impact of certain proposed development projects, but much literature is the result of an increase in environmental awareness and an increased understanding of the value of natural areas for research. Over 200 articles have been written about Illinois Nature Preserves since 1964, when the first nature pre-
serve was dedicated. One hundred and five permits have been issued since
96
1973 for research projects in Illinois Nature Preserves, including 40 per-
mits in 1977 (Illinois Department of Conservation, 1978).
PART V RESULTS AND CONCLUSIONS
The results of the project are summarized in Part V. Survey methods are evaluated, and major characteristics of natural areas are described. Activities are suggested for using and
updating the results of the inventory.
98
Plate 7. A red squirrel along the Kankakee River. Thts spectes, also knoum as the pine squirrel, was thought to have been eliminated from the state shortly after 1900. Investigations by the Inventory staff revealed that the red squtrrel tnhabtts at least four northern Illinots counties.
99
Section 24. EFFECTIVENESS OF THE METHODS
Introduction
This section analyzes the effectiveness of various sources of infor- mation for identifying natural areas. Both compiling available informa- tion and conducting new surveys are necessary for an adequate inventory. Because a partial inventory can be done by compiling only the existing information, an estimate is made of the number of areas that would have been found if the project had stopped at this stage. The number of areas
that may have been overlooked despite all efforts is also discussed.
Finding Significant Features
Compartson of methods
The next several paragraphs are based on a study of the way in which each Category I, II, and III significant feature was found. No useful comparisons can be made with Category IV, V, and VII features because the surveys of these sites relied almost solely on existing information. Too
few Category VI sites were identified to allow a useful analysis.
The following tabulation analyzes the number of areas that would have been found--or would have been missed--if the Inventory had relied solely on accumulating the existing information about natural areas, with- out new surveys (such as examining aerial photos, etc.):
Cat aylGat. pli Gate Lit
A. Number of significant features that could have been found by compiling available information:
1. Number that could have been found only by compiling available information. ..... 60 403 13
2. Number that could have also been found by MeWwesUrveyse- ses toe BSTh O64 BEMOns Foye. 235 32 23
B. Number of significant features that could have been found only by conducting new surveys. . 394 86
TOTAL significant features, found by all methods. 689 521
> uw |
100
The above figures are broken down in the following three tabulations to
show the actual or potential source of information for each area.
For significant features that could have been found only by compil-
ing available information (line A-1 above), the source was:
Cake Cat. bl Cate pms
Contaccsmwath Peopllciiear-al lien menu 2, 156 8 Unpublished files, herbarta, ete... e - 23 7S 4 Review ror literature.) es 2 yee eee eee 10 74 1
For significant features that could have been found either by compiling available information or conducting new surveys (line A-2 above), the source could have been either:
Catal Gacy ule Gace
Compiling available information:
ComEAGES Watelh reels, 5 5 6 o 6 on © Pi 14 20
Unpublished files, herbaria, etc. . 206 18 3
RYenialey” he Isrts, 6 yp 5 6 6 6 Zz 0 0 Or,. conducting new surveys:
Mapssand dertale plOCOS amine me 193 3 16
NETH SURAT eB GEG 0) Oy Deed Seon ec 23 1 4
GroundysunVeyecem ea." omenc ORCI on - 19 28 3
For significant features that could have been found only by conducting
new surveys (line B above), the source was:
Gatti" Cat. Mie Cabreeece
Maps and saeraall phiotos sm -mr-n-mromr-l nn 290 1 1 Nereeil GURAWENE 5 5 6 6 6 a 0 6 50 6 6 0 € 81 3 4 (Gretobigiel SwneyEfe pen 6 6 6 po oO 6 o oe 23 82 4
In the above analysis, compiling available information was given priority over conducting new surveys. That is, if it would have been possible to find an area by compiling available information, then the area was counted as such--even though the area may actually have been found by examining aerial photos or other means. The next tabulation shows how effective each method would have been if it were the only method used. Significant features that could have been found by either
method are counted twice in this summary.
10]
Catemie Cats ehhiCat Mil
Significant features that could have been found by: Relying on previous information Only SIs Bele S5Fiat2 Bit 295 435 36
Relying on new surveys only . - - 629 118 32
Adequacy of available information The information gained from available sources is often not adequate for determining whether an area is significant. The following analysis applies to significant features that could have been found by compiling existing information: Cat apie Cat el Gabe ye ul Would not have required fieldwork to check Smomiga cance. tne seve. 72 1 200 381 23 Would have required fieldwork to check S1oniereances MOF. SLO Ole. G8s 95 54 12 This tabulation includes only significant features that were actually listed by the Inventory. If the project had relied solely on past work without checking sites to learn whether they were significant, then many sites would have been included that do not qualify as natural areas. Less than half of a list of 500 potential natural areas compiled from the files of researchers and natural resource agencies qualified as sites of statewide significance. If the Inventory had accepted this information without further investigation, about 260 areas would have been included
that did not qualify in the inventory.
The value of current information based on field surveys is illus- trated by the inventory of hill prairies. Dr. Robert Evers published Hill Prairies of Illinois (Evers, 1955), based mainly on fieldwork in 1950 and 1951. He described 61 hill prairies and limestone glades, most of which were relatively undisturbed. The Inventory recognized 16 of these 61 sites as natural areas, and added 102 more areas with natural hill prairies or limestone glades. Dr. Evers' classic, pioneering work was completed 25 years ago, and he found most sites by driving along river bluffs. The Inventory relied on maps, aerial photos, and aircraft,
followed by ground checks. The Inventory staff discovered many more hill
102
prairies and learned that some that were significant in the 1950's had
succumbed to woody invasion and grazing.
Published natural area studies do not necessarily include areas of statewide significance, because the studies use different criteria. Two recent county inventories (Wilhelm, 1978; Bell and Zales, 1977) included a total of 63 areas, but only 34 of these sites were listed by the Inven- tory. Without investigations beyond a literature review, the staff would
not have known whether some of the sites met the Inventory's criteria.
Surveys of individual counties are likely to include areas that are not of statewide significance, but an inventory of nationally significant areas should not include any areas that are not of state significance. Shepard and Boggess (1971) and Goodwin and Niering (1975) compiled lists of sites in Illinois recommended for possible registration by the nation- al Natural Landmarks Program. They included 10 forests, prairies, and wetlands--by compiling information available from literature, people, and agencies. Three of these 10 sites did not meet the Inventory's criteria as ecological areas of statewide significance, and the Inventory found 50 additional sites that probably would have exceeded the minimum standards
for the previous studies.
Aside from the problems of overlooking significant areas and mis- takenly including areas that are not significant, an inventory that omits field surveys is limited by the uneven amount of information available for different areas. A bare minimum of information for all areas can be
considered uniform as a basis for making comparisons.
Screening Potential Natural Areas
The previous tabulations dealt with the numbers of significant fea- tures that were actually identified by the Inventory. This revealed how effective each of the inventory methods was for producing the end results. The following tabulations consider the methods from a different point of view, by analyzing how effective each of the inventory methods was as a
practical means of finding and screening potential natural areas.
The following analysis is based on 1,000 potential natural areas from 33 randomly selected counties. The figures in the tabulation have been divided by 10 and (usually) rounded to whole numbers so that the numbers can be read as percentages. Only areas with potential Category I significant features were considered, and the cemetery survey was ex- cluded because of its unusual methods. The inventory methods are con- densed into four stages: (1) compiling available information (reviewing literature, contacting people, etc.), (2) examining maps and aerial pho- tos, (3) aerial surveys, and (4) ground surveys (including initial ground survey and final field survey). Each of these four stages is treated in a separate tabulation as a source of potential natural areas, and the following figures are given for each: (1) total number of natural areas considered, (2) number of sites that qualified as natural areas, (3) num- ber of sites out of the total that were rejected by each of the inventory
stages.
Source: Avatlable tnformatton
Compiling available information had one of the highest rates of re- turn (38%) in terms of the number of natural areas identified for the number of potential natural areas considered. A high percentage of the areas identified from existing information consisted of Illinois Nature
Preserves and other well known natural areas.
Percent “ofpareas, considered... .hektianeh: «sete J ends Natural areas adentifitledton? er sere .lericies ei toeS
Potential natural areas rejected, by: Available information. : Maps and aerial photos Aerial survey.
Ground survey.
BNR Re
Source: Maps and aertal photos
Examining maps and aerial photos produced 73% of the potential natu- ral areas, and 62% of these were quickly screened by the aerial survey. About one out of 15 of the potential natural areas selected during the map and aerial photo examination stage actually qualified as a signif-
icant natural area.
104
Percentiior faréas aconsadered's) situs are eee een. en Natural’ arcas lidentitieda lit. -sionee saaaae 5 Potential natural areas rejected, by:
Ava lable sin formatlOn.a cmc ssn ecu mncune 1 Maps and aexal® photos tee. s. ee enema 5 Aenvallosumvieyia NS, « VORAULEAON See Sa TIES Ground ‘survey: swe: Gigs ce con meCLn ey Melis
Source: Aertal survey
About two-thirds of the potential natural areas selected by the aer- ial survey were potential railroad prairies. One out of 11 of the poten- tial railroad prairies qualified as a natural area. Most of the other
sites found during the aerial survey were hill prairies.
Percent, of sanecas scons dered. 9a. creel alec ace co nee oe Natural vareas, -1adeniGadted..” sas) a4 ipa leanne) Womucnes 1) a!
Potential natural areas rejected, by:
Available information. : s ae, et 0 Maps -andeaerialesphotosie.se. hs at. eee eee 0 Aerial survey. eed ck 4 ; 0.1 Grotmid) -SuUrViGVien cso: yo. io ueg Son ac ea eee ee
Source: Ground survey Less than 1% of the potential Category I natural areas were found by
ground surveys unsupported by previous investigations.
PenHeerierone Bide (comculclesdecln | gee. em er - 0.4 Natural. areas) didenticiied cn capcaneecmen eich ee 0.2
Potential natural areas rejected, by:
Available information. . . 0 Maps and aerial photos 0 Aerial survey. oat Ground survey. (aul
Importance of Experience
Experience was an important factor in determining work efficiency. With practice, the fieldworkers became proficient at aerial surveys and at map and aerial photo examination techniques. Time was saved in two ways: (1) As the ecologists became familiar with procedures, they worked more quickly. (2) More importantly, in the early part of the survey
fieldworkers chose potential areas of questionable value to avoid over-
looking significant sites. After the staff had checked enough sites on the ground, they learned how to increase selectiveness but still have a
reasonable margin of safety.
For example, during the second year of the Main Survey, a larger pro- portion of the forested areas were rejected by examining old aerial pho- tos. The staff had learned that if a forest had a long history of heavy grazing, it would not recover to a natural structure and composition even after 20 years of protection. If a forest had a natural-appearing canopy on a recent photo, but examining a series of photos from the 1930's through the 1950's revealed that the forest had been heavily damaged by
grazing, then it was safe to reject the area.
During the second season's aerial survey, it seemed more difficult to evaluate many forested tracts. Usually the evaluation was either in- stantaneous--the forest had recently been logged or cleared--or it was difficult to determine from an airplane whether the forest had been dis- turbed. The fieldworkers had become so proficient at studying aerial photos that it was difficult to see any more disturbance from an airplane unless the disturbance had occurred after the photo was taken. Increased proficiency at aerial surveying is demonstrated by the fact that many of the sites selected during the early part of the aerial survey of railroad prairies were obviously insignificant to the fieldworkers when they flew
along the same tracks at a later time.
Completeness of the Inventory
Category I survey
The staff was able to quickly screen potential areas and concentrate on describing and evaluating the most significant sites. All of Illinois was studied with maps and aerial photos. Every site found with signif- icant potential for undisturbed natural communities was examined in the field. For example, all river valleys were checked for hill prairies and seeps. All open land on sandy soil in prairie regions that was not ob- viously disturbed was checked for sand prairie. All railroads and all cemeteries that could be found in prairie regions were checked for prai-
rie remnants. Every tract of timber of 20 acres or larger with a natural
106
appearing structure was selected from aerial photos and checked in the field. All wetlands were studied on maps and photos, from an airplane,
or on the ground.
It is difficult to estimate what may have been missed. The field- workers eliminated the obviously disturbed areas and checked the remain- der. The relatively large number of potential natural areas that were eliminated during the screening process indicates that preliminary stan- dards were low enough that few significant sites were overlooked. Consid- ering that 88% of the potential natural areas did not qualify as natural
areas, it is unlikely that many undisturbed areas were overlooked.
The number of sites that would have been missed if the available information accumulated through the years about natural areas had been completely ignored gives some idea of the thoroughness of the Category I survey: 60 out of the 689 Category I significant features probably would have been missed. This includes 22 caves, 14 prairies, eight seeps, and two forests. The remaining 14 sites include barrens, fens, bluffs, over-
hangs, and a pond.
The high percentage of caves identified by existing sources is because there was little searching for caves beyond what was necessary to check the significance of ones that had already been identified as impor- tant. Although caves were considered to have Category I significant fea- tures just as any other kind of natural community, the Inventory relied on information for about 300 caves compiled by the Illinois Speleological Survey. Work by the Speleological Survey, by Bretz and Harris (1961), and by Peck and Lewis (1978) shows that the most outstanding cave ecosys-
tems are usually the caves that are large and generally well known.
Eight of the 29 seeps listed as significant features would not have been identified if available information had been ignored. This is a high ratio because many of the seeps are small (some less than one-tenth acre) and the small ones are not always evident on maps, aerial photos,
or from an airplane.
The Category I significant features that have been overlooked are
most likely small natural communities or remnants that cannot be found
107
by conventional map, aerial photo, and aerial survey techniques. In over a year since the survey to find Category I natural areas ended, informa- tion from others has added three more areas: two seeps and one eroding bluff. Two possibly significant prairies have also been reported. Only time will tell how many new areas will be discovered, but most of the areas that were missed probably will remain unknown. In terms of total acreage of Grade A and B significant features, the inventory probably is
close to complete.
Category II survey
Much work remains to be done with endangered species. Even though the Inventory listed 1,431 occurrences of the species considered in the Category II survey, no natural areas were identified for 18% of the ani- mals listed as endangered or threatened by the Endangered Species Protec- tion Board and 26% of the plants listed by the Endangered Species Project. The Inventory's contract with the Department of Conservation required only a compilation of available information for the endangered species survey, but field surveys were conducted when possible to add new sites and to confirm previous reports. The staff helped the Endangered Species Project organize information from other sources, but in some cases the Inventory did little more than identify large gaps in the knowledge about
the state's flora and fauna.
Category III survey
The inventory of Category III significant features probably was thorough. Relatively few new sites met the Inventory's criteria. The significant ones were almost always in extreme sites that had already been investigated because they were so obvious. Many other sites that had less potential were searched to assure that initial selection stan-
dards were liberal enough to avoid overlooking sites.
Category IV survey
The geologic areas were chosen to make a system of sites represent- ing the geologic features of Illinois. Some areas are obviously the best choices for representing certain features; but in many cases, any one of
several sites could have been chosen. Depending on the emphasis given to
108
the different kinds of geologic features (rock outcrops, landforms, fos-
Sils, etc.), other sites could have been listed.
Category V survey
The survey of school natural areas and nature preserves relied on compiling available information, especially a mailed questionnaire survey. A response was requested from every school, even if the school used no natural area, and a 52% response was received from elementary and second- ary schools--which is creditable by some standards but was not satisfac- tory for a survey that emphasized thoroughness. Persistence in contacting people allowed a nearly complete coverage of colleges and universities. However, at least 40 more areas are known that would probably qualify as
Category V areas if enough information about them could be obtained.
Category VI survey
The Category VI significant features are unique features that did not fit in any of the other categories. Thirty such significant features were listed, and a few more may eventually be added. If the Department of Conservation decides to list areas outstanding because of their inver- tebrate fauna or nonvascular flora, then this natural area category could
be greatly expanded or another category could be added.
Category VII survey
As described in Section 22, the Inventory listed only lakes and streams that were recommended by the staff of the Illinois Natural His- tory Survey. The Survey listed areas that, based on studies of aquatic fauna, are exceptionally outstanding and in need of preservation. Other lakes and streams of lesser significance could have been added, and new field surveys specifically to evaluate the natural quality of lakes and
streams might reveal other significant sites.
Summary
All of the inventory methods were necessary to complete a comprehen- sive natural areas survey. Compiling available information was a basic step; but, except for most endangered species occurrences, this informa- tion was often too incomplete to determine whether a potential site
qualified as a natural area. Examining maps and aerial photos revealed
109
most of the Category I significant features but revealed relatively few endangered species sites. Studying maps and photos assured that the search was systematic and thorough, and it provided a large number of potential natural areas at a low cost. Most of the candidate areas were screened with an aerial survey, which was quite effective: the aerial survey cost less than one-twentieth of the total survey budget, and screening sites without an airplane would have taken seven to 10 times as much time and money. Also, many significant natural areas could have been overlooked without the aerial survey. Almost no natural areas were discovered during ground surveys unsupported by the previous inventory stages such as examination of maps and aerial photos. Within the limita- tions set by the Department of Conservation's guidelines, the surveys were as thorough as practical. The most likely categories for finding new areas in the future are the kinds of areas for which the Inventory
relied on available information.
Yate bros Thee sta? eotumeeyrts wn nl ; iP Reed son a ck had
_ tn. totmun_opte! @ bebiverg ai bis typeof bw 93
axé siehj bans af 3a 2204 9 .2ep4, Api, 2 an speeded
Ingman oft pec aaate, eahup, ax, ot ae dela Ost
bis. .joghs votive J8jo7 Att. Loeb negeens fugt2, azat,
mer. | h teves, podad, suns hfe one sieay a 2azt,
' (J OD. mae. Cpe tins tipok? dum be Mr eed, = “OeMIOM, DAR, ¢
ow, eee, Lomita on seal, | ravine tate, ait, wate >
; wet # 1% Ott ud Dartoggue(iL. Rye vee. Luma czaabs, dy
pli. eosin Lattos, bie gute 3p Apts timekes ee
vat oot. toni absig: 24 ot Saye oRe) FOF Reb allele
t 10% esitogete> yloAll Jeom ofl ...eotzoery 28 Aguozor a
novel af? Hoditw yO? 2gexe Yo 7 stata ods ete emsut adt ob spate,
Lae: ; nije *eaturet that cue
POL? wero seh sidaliova on 1 cane 1
: bol i ] dd 4 é 4 chi os i - , ' ’ seavee of thelr tt ; floragy > the nral arom CQlagusy ee : —_
9 s ’ @
re — ; : otexir tr?
whetho a
Section 25. SUMMARY OF NATURAL AREA CHARACTERISTICS
Number and Distribution of Natural Areas and Significant Features
Number and distribution by county
Figure 2 shows the total number of significant features that occur in natural areas in each county. This information is summarized in Table 4. Sites were recognized in all but three of the 102 counties. Natural areas with high quality communities were found in all but eight counties. Sixty-one counties have endangered species sites, 15 counties have relict species sites, and 56 counties have geologic areas. There are nature preserve and school natural areas in 76 counties, unique natural areas in 20 counties, and outstanding aquatic areas in 17 counties. The aver- age county has 10 or 11 natural areas. Eight counties have over 30
areas: Cook, Lake, Pope, Will, Winnebago, McHenry, Johnson, and Union.
Number and distribution by Natural Divtston and Section
Table 5 gives the number of natural areas and significant features in each Natural Division and Section. The factors that have influenced the number of natural areas in the different natural regions of the state
are discussed below.
A broad but uneven dtstrtbutton of natural areas
One of the best ways to see how natural areas are distributed is to study their location by topographic quadrangle, because the quadrangles form a regular grid, as opposed to the irregular sizes and shapes of counties. Two hundred and eighty-nine 15-minute topographic maps cover Illinois, including about 80 maps that cover only part of Illinois be- cause they extend into another state. There are natural areas in 226
(78%) of these quadrangles (Figure 3).
In general the sites are clustered, and large parts of the state are nearly devoid of natural land. The sites often occur in lines, such as several prairie remnants along the same railroad track--the only un-
disturbed land in the county. Other prominent lines of natural areas
ale ane anaal
zi ef mack
ee et
ian
ie oa i =
it Pe Es
Category VI
Figure 2. Number of significant fe continued.
113
atures (by category) in each county
Figure 3. Distribution of natural areas according to 15-minute topo- graphic quadrangles.
aie bss
occur on river bluffs, especially in Pike and Monroe counties, where hill prairies are common atop the high, southwest-facing cliffs. Hill prai- ries are also clustered in the steep side valleys that form where the Illinois and Embarras rivers cut through high glacial moraines. Natural areas of all kinds are clustered around cities, where public parks and preserves have protected and restored the natural landscape. On the broadest scale, natural areas are absent from the flat prairie land that
is almost completely farmed.
Over half (52%) of the natural areas occur within 15 miles of the boundaries of the state. One reason is that many undisturbed sites are on the rugged bluffs and undrained bottomlands along the rivers that form the western and southern boundaries of Illinois. Similarly, many geolog- ic areas were selected on these river bluffs and in the Coastal Plain sediments that barely enter southern Illinois. The large number of en- dangered species sites in extreme southern Illinois is partly fortuitous: if the state did not extend so far south, these southern species would not be in the state at all; and if Illinois extended much farther south, some of these animals and plants would be so common within the state's boundaries that they would not be considered endangered. The situation is similar in northern Illinois, where many plants that are common not much farther north barely extend into wetlands in the northern tier of counties. The limestone bluffs and ledges along the Mississippi River on the southwestern border of Illinois provide habitat for several western animals and plants that range no farther into the state. The distribu- tion of Category I natural areas is tied to land use patterns, as dis-
cussed in Section 26.
Distribution in relation to human populatton
Natural areas are most concentrated in the counties with population extremes. The four most populous counties (Cook, DuPage, Lake, and Will) rank first, twenty-seventh, second, and fourth, respectively, in number of natural areas. Pope County, the least populated county, ranks third in number of natural areas. Illinois has nine Standard Metropolitan Sta- tistical Areas (SMSA's), which are counties or groups of counties with
population centers of at least 50,000 people. (For example, Sangamon
116
County is the Springfield SMSA, and Winnebago and Boone counties form the Rockford SMSA.) There are 359 natural areas inside the SMSA's, which means that nearly one-third of the sites identified by the Inventory are in or very near major population centers. One hundred and seventy-one natural areas (11%) are wholly or partly within the corporate boundaries of cities, towns, or villages, and half of these natural areas have Cate-
gory I significant features.
Natural Characteristics
Acreage
Natural areas average 184 acres and range from less than 0.1 acre to 13,100 acres. The smallest are sites with endangered or relict species, and the largest areas encompass cave systems and habitats of river otters and greater prairie chickens. There are about equal numbers of natural areas }distributed among fourysizelclasses:) 021 to 5.0 jacres, 5). atom25
acres, 26.to 80.acres,, and oi) jto US. 00saeres:.
Diverstty
Diversity of a natural area is defined in this project as the number of natural communities that are at least Grade C quality. The average natural area has three such natural communities, but five sites have 10 or more communities: Illinois Beach Nature Preserve (16 communities), Illinois Beach North Tract (15), LaRue--Pine Hills Ecological Area (15), the Little Black Slough--Heron Pond--Wildcat Bluff area (15), and the Apple River Canyon area (10). Areas with great topographic relief gen- erally have high diversity: the 23 natural areas with 300 feet or more of relief have an average of six natural communities. Diversity of com- munities is related more to diversity of soils than to relief: Illinois Beach, the most diverse natural area in Illinois, has only 30 feet of relief and owes its diversity to the many small habitats created by al-
ternating swales and ridges of sand.
Topography The topographic diversity of Illinois is well represented in sites identified by the Inventory. Natural areas were recognized in all 16
physiographic units (Appendix 4) defined by Leighton, et al. (1948).
Most of the 61 major topographic features in Illinois according to the classification by Dr. H. B. Willman (Appendix 5) are in natural areas, except for a few features distinguished from others on the basis of loess thickness. Nearly all of the 64 individual topographic features (Appen-
dix 6) were found in one or more natural areas.
Geologte formattons
Appendix 7 lists the geologic formations in Illinois (Willman, et al., 1975), with the number of times each formation occurs at the sSur- face in a natural area. One hundred and twenty-seven (or 89%) of the 143 named formations in Illinois occur