Assessment of abandoned mines for bat use on Bureau of Land Management lands in the Phillipsburg, Montana area, 1999 PDF
Preview Assessment of abandoned mines for bat use on Bureau of Land Management lands in the Phillipsburg, Montana area, 1999
Assessment of Abandoned Mines for Bat Use on Bureau Land Management of Lands in the Phillipsburg, Montana Area, 1999 A Report to: Bureau ofLand Management Missoula Field Office 3255 Fort Missoula Road Missoula, Montana 59801 Submitted by: Paul Hendricks January, 2000 MONTANA ^iI ^^AfCv Natural Heritage Program L.AV * S •• 599.41518 -N11AAMP 2000 1 ^kj^tdU. MontanaStaleLibrary 3 0864 1004 3984 6 oi aanssi ©2000MontanaNaturalHeritageProgram 1515EastSixthAvenue, Helena, MT 59620-1800 Thisdocument shouldbecitedasfollows: Hendricks, P. 2000. AssessmentofabandonedminesforbatuseonBureauofLand ManagementlandsinthePhilipsburg, Montanaarea: 1999. MontanaNaturalHeritageProgram. Helena, MT. 13 pp. ABSTRACT InJuly 1999, threegroupsofabandoned mineworkingsonBLM lands in thePhilipsburg, GraniteCounty, Montanaarea wereinspected fortheirpotential use by bats. Sitegroups included the RussianGulch Mine(2 adits), FrostCreek groupadjacent to Philipsburg(5 adits), and theCliffCreekgroup, also adjacent to Philipsburg(7 adits, 1 shaft). Wherepossible, workingswere inspected internally forbatsand bat spoor, at sites suitableand withgreatest potential, mist netswereset acrossportalsand monitored fortwohoursaftersunset All butthe Russian Gulch Minewereshallowworkingsorinaccessible, and all workingsexhibited low activityor low potential for significant usebybats TheRussianGulch Minecould be made more accessibletobats, and hasthegreatest potential forsignificant use, butanothernearby working (SilverKingMine) showed current bat activity (asof1997)and is preferable forbat- friendly reclamation iflimited funds preclude management forbatsat both mines. Fivebat speciesthat usecavesand minesasprimary hibernation habitat havebeen recorded from GraniteCounty, and havethepotential tooccurinabandoned mineworkings in thePhilipsburgarea These species includetheWestern Small-footed Myotis(Myotis ciliolabrum). WesternLong-earedMyotis(M evotis), LittleBrownMyotis(M. lucifugus). Long- legged Myotis(M volans), and Townsend'sBig-eared Bat (Corynorhmustownsendii) All but the LittleBrown Myotisare U.S. Fishand Wildlife Service Special Concern species, and Townsend's Big-eared Bat isalso aBLM Special Status species in Montana ACKNOWLEDGMENTS ThisprojectwasmadepossiblethroughsupportoftheMontanaNaturalHeritage Program-acollaborativeeffortofTheNatureConservancyandtheNaturalResource Information System-andaChallengeCost ShareagreementwiththeMissoulaFieldOffice, BureauofLandManagement. I especiallythankDaveMcCleereyoftheMissoulaFieldOffice forencouragementandcontinued supportinnearlyall facetsofabandonedmine surveysfor bats, and forhisinterestinbatbiologyand management ingeneral. INTRODUCTION Several speciesofNorth Americancave-dwellingbatshavebeenadversely affected in recent decadesbyavarietyofhuman-induced environmental changesto caves, includingcave closures, impoundments, and vandalism orotherdirect humandisturbances(seeHumphrey 1978, Tuttle 1979, LaVal and LaVal 1980, Sheffield et al. 1992). These, and landscapechanges suchasdeforestation(including lossoflargetreeswith basal hollows) and agricultural development, have forced many bat speciesto abandontraditional sites in searchofnewroosts and hibernacula Asaresult ofthesewide-spread disturbances, somecave-dwellingspecies in theeasternand Midwestern United States havebeen listedasthreatenedorendangered underthe U.S. Endangered Species Act. Abandoned minesofferavariety ofsubterranean microclimates similartothoseinnatural caves(Tuttleand Stevenson 1978, Tuttleand Taylor 1994)and can providesuitablehabitat forroostingand hibernatingbats Abandoned mines now serveas principleroostsand hibernacula formany cave-dwelling species(Tuttleand Taylor 1994), and areimportantforpopulationsoccupying marginal habitats(Gatesetal. 1984) inareaswhere therearecontinued threatsto primary naturalroosts. It iswidelyacknowledgedthat natural cave environmentsarethe most stableand desirable long-term habitatsforbats, butabandoned mines may provideasuitablealternative Minereclamation(includingclosuretorestrict human access) isofinteresttowildlife managersbecausereclamationactivitiescan have significant negative impactson bat populations (see Sheffield et al. 1992, Richteret al. 1993) Therefore, it is importantthatclosure isdone in such awayastominimizedisturbancetobats inthe minesaffected. Becausethe majorityofbat species in Montana usecavesand mines, it isespecially importanttodeterminethe extent and magnitudeofmineuseby bats inthe state, and identify situationswhereaccess by humansto abandoned minescan be restricted while maintaining mineattractivenesstobats. Increased concernoverbat populationsnationally, coupled with increased emphasison theclosureofabandoned mineson public lands, hasprompted BureauofLand Management (BLM)biologists inMontanatoassessabandoned mines forbat activitypriorto mineclosure (e.g., Hendricks 1997, Hendrickset al. 1999). Anumberofabandoned mines inwest-central Montanaon BLM landsunderjurisdictionoftheMissoulaField Officeare scheduled forclosure in the near future Someofthese mines may provide habitat critical for hibernation, reproduction, and warm-season roosting by bats, includingTownsend'sBig-eared Bat (('orynorhmustownsendu), adesignated Special Status speciesby the BLM in Montana. Objectivesofthe surveys reported here include 1) assessingthe suitability ofseveral abandoned mineworkingsasbat habitat, and 2) providing management suggestionsthat assist in reclamationactivitiesattheseworkings STUDYAREAANDMETHODS Threegroupsofabandoned mineworkingsinthePhilipsburg, GraniteCounty, Montana areawereidentifiedbyMissoulaFieldOfficeBLMpersonnel forassessmentasbathabitatprior toreclamationactivity. TheseincludedtheRussianGulchMine(2adits) aboveRock Creek about 11 milesWSWofPhilipsburg(T6NR15WS8NWSE; 5200ftelevation), theFrostCreek workings(5 adits)just SEofPhilipsburg(T7NR13WS30SEand S31NW), andthe"CliffCreek" workings(7adits, 1 shaft), alsojust SEofPhilipsburginthenextdrainagenorthofFrostCreek andsouthofCampCreek(T7NR13WS30SW); elevationofworkingsintheFrostCreekand "CliffCreek" groupsrangedbetween 5600and6000ft. Thelasttwogroupsofworkingsexist amongaconfusingclutterofotheroldminingactivityonpatentedclaims,thereforesite designationsfollowthoseprovidedbyBLMpersonnel (DaveMcCleerey andMindyMason)as showninFig. 1 (FrostCreekworkings) andFig. 2 ("CliffCreek" workings). Mineworkingswerevisuallyinspectedforbat spoor(guano, insect parts,bats themselves). Configurationand sizeofportalswererecordedandnotestakenonentrance stability. Wheredeemed safeand suitable, mineswereenteredand inspectedinternally. If possible, mineairtemperatureandrelativehumiditywererecordedatmeasureddistancesfrom portalsusingaBacharachslingpsychrometer. Airmovementanddirectionwerealsonoted, and extentofundergroundworkingswasmeasuredusingametertape. Ultrasoundelectronicbatdetectors(ANABATII; TitleyElectronics, Ballina, Australia) wereusedatworkingsthatappearedtohavegreatestpotential forusebybats, orwherefor safetyreasonsopenworkingswerenotinspected internally. Theseunitsare sensitiveto broadbandultrasoniccallscommon in batvocalizations(usually20-180kHz). Callsare capturedandconvertedtoanaudiblefrequency, andrecordedon magnetictapeforlateranalysis. Detectorunits(consistingofadetector,timer/tapedriverdelay switch, and avoice-activatedtape recorder)weresetupbeforeduskatmineportals(facingintotheadit) and leftovernight. RecordedcallswereanalyzedonanIBMcompatiblePCusingANABATZCAMsoftware. Assignmentofvocalizationstoaparticularspeciesofbatisachievedby matchingfield recordingswithreferencesetsofcallsordescriptionsfromthepublished literature(e.g.,Fenton etal. 1983, O'Farrell 1997). However, bat speciescanshowsignificantvariationincall structure(Betts 1998,Barclay 1999), and flyingbatswerenotactivelytrackedandrecorded (O'Farrelletal. 1999)tomaximizequalityandquantityofdiagnosticsequences. Furthermore, unitsweresituatedweretheywouldrecordbatsexitingroostsorflyingnearpotentialroosts. Roost-exitcallsandcallsinhighcluttertendtobefragmentary, lackingdiagnosticfeatures necessaryforspecies identification(O'Farrell 1999). Therefore, all species-level identifications basedonrecordedvocalizations, wheremadeduringthissurvey, areconsideredtentative. Mistnets(50denier, 2.6mlength)weredeployed atduskacrossmineportalswhere deemedappropriateandleft openfortwohours. Duringthissurveynettingoccurredonlyatthe RussianGulchMine. ThedatabasesattheMontanaNaturalHeritageProgramwereexamined forbatrecords fromGraniteCounty. These includemuseum specimensand otherobservations, and indicatethe potential arrayofbat speciesthat coulduseabandonedmines inthe surveyarea. Alist of databaserecordsisprovided intheDiscussionsectionofthisreport. RESULTS Russian Gulch Mine: TheRussianGulchMineworkings(T6NR15WS8NWSE)consistoftwo openadit portalsand onecompletely collapsed portal. Thetwoopen portalsareconnected by theunderground workings Theupper, southern portal wasentered on9July 1999. The passage slopesdownward andtothe N for 11 m, where it intersectsadrift that runs level approximately E-W for47 m. Abouthalfway alongthispassage it intersectsanotherpassagethattrends downward(N)for 13 m Thisthen intersectsasecond E-Wtrendingdrift The second (northern)open portal is28 mtotheW fromthispoint. Totheeastthereisconsiderable breakdown beyond 10 m, andthe full extentofthispassagewasnot explored Dry bulb temperaturesat eitherend oftheconnecting(13 m) passagewere43°Fwith94% relative humidity. Drybulb temperatureatthe S portal was77°F(relative humidity=25%)atthistime (16:30MDT). Total measured passagewas 109 m, with largest dimensionsofabout 2 2 X 1.5 m (height Xwidth). Height and widthofthelargest open portal (the southernone)were0.7m and 15 m, respectively Therewas littleevidenceofhuman disturbanceand theworkingsare essentially dry. Warmairgently flowed intothe minethroughthe southern portal, coolerair flowed out ofthe minethroughthenorthernportal. A Bushy-tailed Woodrat (Neotomacinerea)wasobserved intheupper47 m drift, where Porcupine(Erethizondorsatum)droppingswerealso present. Nobatsorbat spoorwereseen duringthe hour-long inspection The southern portal wasnetted fortwo hours(21:30-23:30) Nobats werecaptured, and none madepasses neartheportal However, batsmadeabout 16 passes inthegeneral areaofthetwo portalsduringthattime. Most passeswere by some species ofMyutis(based on visual observation)whilea fewpasseswere made bya second largerspecies (perhapsBigBrownBat,Eptesicusfuscus) Nobatcallswere recordedovernight ateitheropen portal onANABATunits. Frost Creek#1: This site(T7NR13WS31SENW)wasnot inspected, perBLM suggestion Frost Creek#2: Thisadit (T7NR13WS31NENW) hasapartially open portal with awooden headffameand shonng, extending level and curvingtothe left inabout 8-10m. It wasnot entered whenvisited on 10July No air movement was noted atthe portal A few intact cobwebsextended acrosstheopening No bat activity wasrecorded overnighton an ANABAT unit Frost Creek#3: Thisadit (T7NR13WS30SESW)in lowerFrostCreek iscollapsed about 6-8m in fromthe portal, headframeand shoring, and has low potential forsignificant useby bats It wasnot monitoredovernight Frost Creek#4: Thisadit (T7NR13WS30SWSE) adjacent totheFrost Creek road consistsofa partiallyopen portal (0 8 m high X 1 9mwide)that leads intoa level drift extending27 m tothe drift face Drift height and width are 2 mand 1.5 m, respectively. A fewcobwebshungacross the portal at thetimeofinspection(13 05 MDT)on 10July Dry bulb temperature atthe drift facewas45°F with94% relativehumidity A fewold bat droppingswerepresent nearthedrift face, buttherewasno evidenceofrecent bat activity Nobats wererecordedon an ANABAT unit left overnight atthe portal Figure 1. Mineworkingssurveyed inJuly 1999 intheFrostCreekdrainagenearPhilipsburg, GraniteCounty, Montana. Figure2. Mineworkingssurveyed inJuly 1999inthe"CliffCreek" drainagenearPhilipsbur^ GraniteCounty, Montana.
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