natural areas of the shawnee national forest · “rare baltimore checkerspot butterflies sail over...

Natural Areas of the Shawnee National Forest

“Rare Baltimore checkerspot butterflies sail over rocky barrens; French’s shooting stars bloom under the drip zones of overhanging cliffs; streams flowing through the forest have intact fish and insect communities, sometimes visible only as ripples in the clear water or as adult insects newly emerged from the stream, quietly resting along the shoreline. Swallowtail butterflies find an interesting mix of nutrients along a woodland stream and congregate in numbers not to be believed.”

—MichaelR.Jeffords

FieldNotesforSpring,2011

Natural Areas of the Shaw

nee National Forest | 3

Natural Southern Illinois

IfasinglewordcoulddefinetheShawneeNationalForest,diversitywouldbemostappropriate.TheShawneeoccupiesanareaofIllinoisjustsouthofwheretheIl-linoianGlacierstoppedduringthePleis-toceneEpoch(~120,000yearsago).Heremassivesandstone,limestone,andshaleescarpmentsstandancient,weathered,andexposed.Today,amantleoftreescoversmostofthelandscape.Glades,wheretherockisatornearthesurface,areopenareasintheforest;rockledgesarewindswept,inhospitableplaceswheretreesgrowonlyaroundtheedgesandintheever-wideningcracksandfaultsintherock.Thedeep,steep-sidedravinesareverdantjunglesofAmericanbeech,ma-ple,andahostofothertreespecies.Theoverarchingfactor,though,istheforest,

primarilydominatedbyoakandhickory,butsupportinggreattreediversityasthemoistureandlandformsvary.

Eventhoughthemajorityoftheoriginalforesthasbeenloggedfrom1–10times,asnotedina1931reportofWilliamL.Barker,andmuchofitfarmedforover100years,withtheadventofitsdesigna-tionofaNationalForestin1933,theShawneebeganit’slongrecovery.Today,theforestisdramatic,dynamic,andbeautiful.

NaturalAreasarespecialplacesintheShawneethatstillreflectthehabitat,plant,andanimaldiversitypresentbeforeEuropeansettlement.Anaturalareais

definedas“anareaoflandorwaterinpublicorprivateownershipwhicheitherretainsorhasrecoveredtoasubstan-tialdegreeitsoriginalnaturalcharac-ter,thoughitneednotbecompletelyundisturbed,orhasfloral,faunal,orecologicalfeaturesofstatesignificance.”Notwithstandingthebureaucraticjargon,individualsknowwhentheyhaveenteredaspecialplaceintheforest.AfurtherdesignationintheShawneeiscalledaResearchNaturalArea—permanentlyprotectedtomaintainbiologicaldiversityandtoprovideplacesforresearchandmonitoringofundisturbednaturalareas.WithevocativenameslikeLaRue-PineHills/OtterPondandPantherHollow,theyarelocationsworthavisit.

dry upland forest

Where Does the Shawnee Fit Into the Biology of Illinois?

Scientistshavedividedtheterrestrialpartoftheearthintolargeecologicalregionscalledbiomes.Examplesofworldwidebiomesincludetropicalrainforest,Asiansteppes,Africansavanna,andahostofothers.TheNorthAmericancon-tinentalsohasbiomes,suchastheArctictundra,Sonorandesert,andAppalachianforest.Illinois,too,hashaditslandscapedivided,notintobiomes,butintoregionscalledNaturalDivi-sions.ThenaturaldivisionsofIllinoiswerepresentedin1973inatechnicalreportauthoredbythenstatebotanistJohnSchwegmanandcolleagues.Theypro-posedthatIllinoisbedividedinto14NaturalDivisionsbasedonsuchcharacteristicsasglacialhistory,soiltype,topography,climate,andthedistributionofnativeplantsandanimals.These14divisionswerefurthersubdividedinto33subdivi-sions.Overtheyears,Illinois’naturaldivisionshaveprovenveryusefultothenaturalareapreservationmovementwithinthestate.Theyhelpbiologistscat-egorizeandprioritizeIllinois’90+naturalhabitatsforpreservationandrestora-tionefforts.TheShawneeHillsNaturalDivisionencompassesagoodportionofsouthernIllinois,includingalloftheShawneeNationalForest.

Left, old growth forest



boundary of the Shawnee National Forest

Shawnee Hills Natural Division

Satellite image of southern Illinoisshowing much of the Shawnee National Forest area.

boudary of the Shawnee National Forest

Importance ofNatural Areas

Otherthanfortheirbeautyandaca-demicinterest,whyarenaturalareasimportant?

•Naturalareasarethegeneticbanksforthearea’sbiodiversity.Theyarebothreservoirsforthespeciesthatshouldbepresentandalsothetemplatesorreferencepointswemustuseforourhabitatrestorationefforts.

•Naturalareascannotbeseparatedfromtheorganismsthatdependonthemforsurvival.

•NaturalareasinIllinoisareourbiologicalheritage,equallyasimportantasourrichcollectionofcultural,historicsites.

IfoneweretopickasingleareaofIllinoistoexperiencenatureatitsfinest,theShawneeNationalForestwouldbeanexcellentplacetobegin.

How Do We Know About the Natural Areas of Illinois? —The First Natural Areas Inventory and the Update

Illinois’naturalareaswereoncefamiliaronlytobiologists,certainlandownerswhorecognizedhowdifferentthatsmallpatchofwoodsorprairiewasontheirland,andahandfulofnaturalresourceprofessionals.Thesesiteswereremi-niscentofconditionsinIllinoisbeforeEuropeansettlementandrangedinsizefromseveralthousandacresofwetlandsalongtheCacheRiverinsouthernIllinoistotinyprairiepatchesexistingalongraillinesorinpioneercemeteriesscatteredthroughoutthestate.TodeterminehowmuchofIllinois’naturallandsremained,astatewideNaturalAreasInventorywasconductedfrom1975to1978.Itdocu-mentednearly1,200sitesacrossIllinoisthatwerebiologicallysignificant.Thisinventorywasaremarkableaccomplish-mentandauniqueundertakingforanareaofthesizeandcomplexityofIllinois.Overthelastfewdecades,theinventoryhasbeenanimportanttoolintheconser-

vationofIllinois’vanishing,rarehabitatsandtheplantandanimalstheyharbor.OnJuly1,2007,anewprojecttoupdatetheIllinoisNaturalAreasInventory(INAI)began.Itsmissionwastodevelopacontemporarylistofnaturalareasofbiologicalsignificance,basedoncurrentIllinoislandscapesusingthebestavailablescientifictechniques.TheINAIUpdatesystematicallyscreenedtheentirestatetofind,evaluate,classify,andmapaddition-alnaturalareas.EventhoughTwenty-firstCenturytechnology—remotesensing,GeographicInformationSystems,anddigitalimaging—isaprominentcom-ponentfortheupdate,itisimportanttonotethatallsiteswerevisitedbyscien-tists.On-the-groundexpertsassessingandmakingthefinaljudgmentsontheoverallqualityofanaturalcommunityremainthemostimportantstepintheprocess.

Natural Areas In the Shawnee National Forest

TheShawneeissignificanttotheIn-ventoryforanumberofreasons:

•theShawneeisthesecondlargestownerofnaturalareaslistedontheInventory,encompassingawidediversityofsites;

•itharborsaconsiderablepercent-ageofIllinois’rarestbiologicalresources.Almost10%ofalltheIl-linoisNaturalAreasInventorysitesarelocatedintheShawnee;

•innearlyadozencases,theShawneesupportstheonlyknownexamplesofnaturalcommunitytypesinIllinois,andthesesitesareirreplaceable.

Far left, eastern tailed blue; left, a dry Shawnee forest; left inset photos, clockwise from upper left, White-breasted Nuthatch, Wood Thrush, gray treefrog, French’s shooting star, elephant stag beetle, milk snake, Azalea in bud, gray squirrel; above, barrens; right, sharp-lobed hepatica Hepatica acutiloba.



PerhapsthebestwaytounderstandthenaturalareasoftheShawneeiswithalist,abriefdescription,andimagesofthebroadhabitattypesthatarepresent.

Upland ForestForestsarecertainlythemostwide-

spreadanddiversenaturalcommunitiesintheShawnee,anduplandforestsdomi-nate.Uplandforestsare,simply,thosethatdonotflood.Severaldistincttypesoccur,however,basedontheamountofmoistureavailableandqualityofthesoil.Agradientfromextremelydry(xeric)tomoistsitesoccurswithintheforest.Althoughallsitesaremostlycharacterized

byoaks,thespeciescompositionvariesconsiderably.Post,blackjackandscarletoaksdominatethedriestsites;thesome-whatmoistersitesincludepost,blackjack,blackandwhiteoaks,andvarioushicko-ries.Furtherdownthemoistureslope,wefindthetypical“oak-hickory”forestsdominatedbyblack,white,northernredoak,andvarioushickories—shagbarkandpignut.Thisisthemostwidespreadforesttypeintheregion.Onthemoistersites,treediversityincreasesandthetreesgrowstraightandtallwithfewlowerbranchesandawell-developedunderstory.TreespecieshereincludeAmericanbeech,sugarmaple,northernredoak,tulippop-

Understanding Natural Communitiesin the Shawnee National Forest

Dutchman’s Breeches

Indian Pink

moist upland forest

oak-hickory forest–spring

oaks in winter

lar,riverbirch,andsycamore.Theun-derstoryandherbaceouslayersalsovaryacrosstheseforesttypeswiththegreatestdiversityfoundonthemoistersites.

Bottomland Forest Bottomlandforestsoccuralongstreams

thataresubjecttoperiodicfloodingandformdistinctcommunities.Treediversityismuchlowerasonlyspeciesthatareadaptedtofloodingpersisthere.

MoistfloodplainforestsoccuralongmajorstreamsintheShawnee.Onlandthathasmoreruggedtopographyandsteeper-sidedvalleys,thefloodepisodesareshortandinfrequent.Dominanttreesarewhiteoak,sugarmaple,andAmericanbeech,butalsoincludeblackwalnut,whiteash,buroak,andpecan.Therealdistinctioninthisforesttype,however,

occursintheunderstoryspecies:lizard’stailandcardinalfloweraretwopromi-nentexamples.Onthewettestsites,thecanopytreesgrowwell,butaregener-allyshorterthanonbetter-drainedsites.Commonspeciesaresweetgum,honeylo-cust,blackwalnut,andsilvermaple.Theshrublayerissparse,buttheherbaceouslayercanbequitethickandincludespoisonivy,giantcane,varioussedges,andgreenbriar.

WoodlandsDistinguishingwoodlandsfromforests

mayseemlike“splittinghairs,”butthedistinctionisquitereal.Woodlandisadrycommunitydominatedbytrees,grasses,andforbs.Thetreeheightseldomexceeds50feetandthetrees,eventhoughtheyarethesamespeciesfoundinfor-



luna mothDutchman’s Breeches

larkspur Red-bellied Woodpecker

moist upland forest

bottomland forest

ests,haveaverydifferentgrowthform.Woodlandtreeshaveahighlybranchedtrunkwithspreadinglimbs.Somecallthem“wolftrees.”Themostprominentspeciesarepostandblackjackoakandblackhickory.Thecanopyisveryopen,theshrublayerissparseanddominatedbyfarkleberry,whiletheherbaceouslayercontainswoodlandsunflower,littleblue-stem,andvariousasters.Fireisextremelyimportantinmaintainingthiscommu-nitytype.

BarrensWhiletheterm“barrens”mayprovide

adistinctimpressionthatmightdeteravisitorintothinkingthesiteisnotworthvisiting,nothingcouldbefurtherfromthetruth.Barrensareuniquecommuni-ties,richinlifeandcomplexinstructure.

Barrensowetheirexistencetoadelicatebalanceofnaturalforcesthatpreventthemfrombecomingatypicalforestcommunity.Unlikeforests,wheretreesdominate,inabarrenscommunitytheherbaceouslayerisequallyasimportantasthetrees.Thelandscapehasmanyvines,lichens,andmossesscatteredaboutinpatchesofopenground,andsurfacerockscontributetotheunstable,oftenpoorsoilconditions.Barrensmaybelocatedonsandstone,limestone,orshale.Theplantcommunities,however,remainverydiversewithwhite,post,andblackjackoakscommon(althoughallarescattered,stunted,andlimby).Theherblayerhasfarkleberry,littlebluestem,Venus’lookingglass,purplemilkweed,Indianpink,NewJerseytea,andahostofotherspecies.AnimalsincludeBaltimorecheckerspot

woodland fire for managementmoss and blackjack oak on sanndstone

celandine poppy

moist upland forest

shaggy mane mushrooms

barrens

butterfliesandeasternhognosesnakes.Fireisacriticalmanagementtooltorestoreandmanagethesecommunities.

Swamp Swampsarerarecommunities,as

mightbeexpectedinanareaofrollingtoruggedtopographythatcharacterizestheShawnee.Infact,theyonlyoccurintheLaRue-PineHillsResearchNaturalArea.Twotypesofswampsarefoundhere:typicalfreshwater,woodycommunitiesdominatedbytreeswithsurfacewaterformostoralloftheyear,andshrubswamps,wheretreesarelessevident.Typicaltreespeciesforbothtypesincludebaldcypress,watertupelo,pumpkinash,andDrummond’sredmaple.TypicalshrubspeciesareVirginiasweetspire,swamprose,andbuttonbush.Uncom-

monherbsincludeAmericanfeatherfoil,copperiris,andkidneyleafmudplantain.

SeepWhilewetlandsarerelativelyuncom-

monintheShawnee,seepsandspringsdooccurinthebottomlandsoftheOhio,Mississippi,andCacheriversandscatteredalongtributarystreamsthattraversetheforest.SpringsarelimitedtotheLaRue-PineHillsarea,butacidseepsarescatteredthroughtheCretaceousHills.Theseseepssupportsphagnummossandareacidicinnature,obtainedfromtheCretaceousgravelsthewaterflowsthrough.Theseuniquehabitatsarefoundalongsmallstreamfloodplainsorflowfromtheslopesoftherollinglandscape.Interestingorgan-ismsfoundhereincludecinnamonfern,royalfern,cardinalflower,craneflyorchid,



long-tailed salamander

American featherfoil

woodland fire for management

moist upland forestswamp with water tupelo and bald cypress

phantomcranefly,red-bandedhairstreakbutterfly,andtheuncommongraypetal-taildragonfly.

Cliff VerticalrockfacesintheShawneeare

certainlycommonandsharethefollow-ingcharacteristic:theyhavevirtuallynosoil,althoughsandcanbefoundonledg-esandalongthebases.Theydodiverge,however,whenweconsiderthetypeofrock—sandstoneorlimestone—andthedegreeofwetnesstheyexhibit.Themois-turegradientisdeterminedbytheaspect(directioninwhichtheyface)andthetypesofsurroundingnaturalcommuni-ties.TheplantcommunitiesarerelativelyuniformacrosstheShawnee,withthenorth-andeast-facingcliffssomewhatmorelushthansouth-andwest-facing

cliffs.Typicalplantsofdrysandstonesitesincludealumroots,spleenworts,andlichens.Themoistersiteshavewalkingfern,clubmosses,wildhydrangea,andpartridgeberry.LimestonecliffsalongtheMississippiandOhiorivershaveasome-whatmorediverseflora.Frequentspeciesincluderedcolumbine,cleftphlox,andvariousferns.Wheretheclifffacesarehollowedout,ledgesoverhangthelandbelowtocreateshelteredmicroclimatesthataremoisteranddarker.HerewefindFrench’sshootingstarandlargecoloniesofantlionlarvaewiththeircharacteristicpits.

GladesGladesdifferfrombarrensbyhaving

moreexposedbedrockandavarietyofmossesandlichens.Theymaybeeither

tiger beetles

fern-covered cliff face

wolf trees

natural rock arch

Garden of the Gods rock formation

sandstoneorlimestone.Inareasofhighvisitation,thegladesareoftentrampledandlittlebutbarerockremains.Pricklypearcactusiscommonlyfound,asissedum.Limestonegladescanbequitespectacularwithdisplaysofeasternpurpleconeflower,wildhyacinth,andNewJerseytea.Easternredcedarandblackjackoakmaydominateandinterestingani-malsincludethelichengrasshopper,therock-lovingcranefly,andolivehairstreakbutterfly.

CaveCavecommunitieshavetwocommon

features—atotalabsenceoflightandnogreenplants.Theymaybewetordry,andmosthaveanintactfaunaadaptedforlivinginthisuniqueenvironment.MostarefoundinlimestoneintheShawnee.

Thetypicalanimalsfoundindrycavesincludecavecricketsandvariousspeciesofbats.Wetoraquaticcaveshavepools,streams,andwaterfalls.Typicalinhabit-antsincludespringcavefishandvariousinvertebrates(mostcolorless)adaptedforthecavehabitat.



cave-dwelling moth

pale purple coneflowers

Baltimore checkerspot

Piney Creek Ravine

sandstone overhang with small cave entrance

Pine Hills limestone cliff

sandstone ledge

WhiletheShawneeNationalForestispubliclandandisprotectedfromdevelopmentinmanyways,itsnaturalareas,andtheforestitself,needsmorethanjustprotection.Overeons,theforestanditsvarioushabitatshavedevelopedinresponsetoenvironmentalfactorssuchasweatherpatterns,fire,andgrazing.Duringthelasttwocenturies,though,relativelylargenumbersofhumans,mostlyofEuropeanorigin,havemovedintoandacrosstheShawnee,oftenalter-ingthelandscapeanditsenvironmentalpatternstofittheirownneeds.Firepatternswithintheforestweredrasticallyaltered(ofteneliminated),thelandwasclearedforagriculture,whiledozensofexotic,ofteninvasivespecieswereintro-ducedandspreadacrosstheland.Whileallthreefactorscanforeverchangeanecosystem,activemanagementbyforestserviceandstatepersonnelcanamelioratethesechangesandreturnportionsofthelandscapetopre-Europeansettlementconditions.Suchactivemanagementandrestorationactivitiesasrestoringnormalfireregimesandremovingexotic,invasivespecies(e.g.,kudzu,honeysuckle)arefarbetteralternativesthantoeitherlosethesehabitatsforeverortotrytorecreatethem.TheShawnee,itsstakeholders,andthestateofIllinoismustworkcooperativelytoformaresilientnetworkofnaturalareasforresearchandforthesheerenjoy-mentofthisresourcethatwecalltheShawneeNationalForest.

Protection and Stewardship

TheShawneeNationalForestisoneofthelargestcontiguousblocksofpubliclandinIllinois,andduetothediversityofitshabitatsandlandforms,itcomesasnosurprisethatalargenumberofthestate’sthreatenedandendangeredspecieslivehere.Wecurrentlyknowofnearly400plantsandanimalsthatfalleitherinthestate’sthreatened(aspeciesthatislikelytobecomeendangeredinthenearfuture)orendangered(aspeciesindangerofextinction)categories.Inaddition,federallylistedspecies,suchasMead’smilkweed,occurintheShawnee.

Theseplantandanimalspecieswhosepopulationsaredecliningorthathavebecomesorareastoputtheircontinuedsurvivalatriskdeservespecialattention.Thesespeciesareimportantmembersofourbiologicalheritageandmustbepreserved.AsE.O.Wilsonsoeloquentlystated,“Theyareamagicwellofeonsoldinformation.”Wemustrememberthatextinctionisforeverandisirreversiblewhenitoccurs.

The Shawnee—A Haven for Threatened and Endangered Species

Upper left, Black-crowned Night-Heron, (state endangered); center left, eastern ribbon snake Thamnophis sauritus (state threatened); bottom left, kidney leaf mud plantain Heteranthera reniformis (state endangered).



Booklet written and photographed by Michael R. Jeffords and Susan Post, and designed by Carolyn Peet Nixon, of the Illinois Natural History Survey, a division

of the Prairie Research Institute of the University of Illinois

natural areas of the shawnee national forest · “rare baltimore checkerspot butterflies sail over...

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