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
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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
Natural Areas of the Shaw
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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.
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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-
Natural Areas of the Shaw
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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,
Natural Areas of the Shaw
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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.
Natural Areas of the Shaw
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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).
Natural Areas of the Shaw
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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