Prospects for Recovering Endemic Fishes Pursuant to the U.S. Endangered Downloaded by [Oregon State University] at 14:25 29 November 2011 Species Act If the successof the Endangered SpeciesAct (ESA) is measured by the number of endangered speciesthat have been recoveredand dellsted, then the act is not very successful. Only 15 specieshave been dellsted becauseof recoveryin the historyof the ESA.The Borax Lake chub (Gila boraxobius), an endangered speciesrestrictedto an Oregon spring system,is consideredto be on the brink of recoveryand may warrant future dellsting. A panel of scientistswas convened to determine consensus regarding the species'listing status by reviewing: (1) current habitat conditions, (2) implementation of the recovery plan, and (3) applicability of ESA listing factors. Despite substantial progresstowards recovery,threats to the speciesremain, including habitat degradation and the potential introduction of nonnative species.These are problems common to many fishes of highly restricted distribution. Becausethe Borax Lake chub occursin a single spring system,the speciesremains vulnerable to catastrophiclossand requirescontinuing protection afforded by the ESA.Like many spring-dwellingfisheswith a restrictedrange, recoveryof the BoraxLake chub to the point where ESAprotection is no longer required is an admirable but largely unobtainable goal. Prevention of extinction rather than dellsting is a more appropriate measure of ESAsuccessfor such species. Jack E. Williams According to Section 2 of the EndangeredSpecies Act of 1973 (ESA), the primarypurpose of the act of endangered andthreatenedspecies until a total of 1,262 species(517 animals,745 plants)were Don W. Sada listed in the United States as of 2003 (U.S. Fish and Wildlife Service[USFWS] 2004a). extinctionsand to provide a means Over thissametimeframe,37 species havebeen wherebythe ecosystems upon which delistedandsubsequently removedfromESA proendangeredand threatened species tection. Of these, 15 were delisted because of dependmay be conserved.The ESA recovery,7 becauseof extinction,and 15 because Jack Williams is chief scientist for tant conservation law in the United Catherine A. Macdonald Cindy Deacon Williams Hal Weeks Georgina Lampman TroutUnlimitedin Ashland,Oregon. He can be reached at jwilliams@tu.org. Macdonaldisthe vicepresidentfor stewardship at The NatureConservancy in Portland, Oregon.Williamsisa fishery consultantin Medford,Oregon. Weeksisa projectleaderwith the OregonDepartmentof Fishand Wildlifein Newport,Oregon. is to stem the tide of human-caused is widelyregarded asthe mostimpor- of new informationor taxonomicrevisionshowing their listingwasin error(USFWS 2004b).The low is duelargelyto inadStatesand is viewedas the pinnacle numberof recoveredspecies of legislationfor protectingwildlife equateprotectionfroma growingarrayof threats (Bean 1983; Plater 2004). Becauseof to speciesand habitats,and becausedelisting its importance and influence, the removesthe primaryregulatoryprotectionavailESA has been the keystone for a growingnumberof conservation bat- able--that is, from the ESA itself (Doremus and Pagel 2001). Indeed, somescientistsand legal havequestioned whetherwe arelikelyto tles acrossthe country. Conflicts scholars andinstead betweenapplicationof the ESA and seethe recoveryof manylistedspecies, that recoveryshouldbe viewedas land and waterdevelopment projects have proposed have increased because of several facan aspirational goalratherthana realisticexpectaLampmanis the Intermountain tion for many listed species(Doremus 2000; tors, but chief among these is the Regionaquaticecologyleadfor the Doremus and Pagel 2001). On the other hand, U.S. ForestServicein Ogden,Utah. cumulative effects of a growing Sadais an aquaticecologistwith human population and increasing others have encourageddelistingsbecauseof the Desert Research Institute in resourcedemand coupled with an recoveryfor a varietyof practical,political,and Reno, Nevada. reasons (Benderet al. 1998). increasingnumberof specieslistedas philosophical The growing list of protected speciesand endangered or threatened. The 30-yearhistoryof the ESA hasbeenchar- increasing human-causedfragmentation and of naturalhabitatspresents a looming acterizedby a growinglist of protectedspecies, degradation for conservation efforts.As conflicts subspecies,and distinct population segments conflagration (hereinafter"species"). When the ESA wassigned escalatebetweenthe ESA and human developinto law by PresidentNixon in 1973, 119 species ment, there are growingefforts to reduce the received"grandfathered" protectionfromthe ear- impactand effectiveness of the ESA. One wayto lier EndangeredSpeciesConservationAct of reducethe impact of the ESA is to reducethe 1969. From 1973 through 2002, an averageof numberof protectedspecies, eitherby slowingthe neady43 species wereaddedeachyearto the list numberof new specieslistingsand/orincreasing 24 Fisheries I www.fisheries.org I vol 30 no 6 the numberof delistings. Forthe first20 yearsfol- Case Study: lowingpassage of the ESA, there were only 18 The Borax Lake delistings, but since1993the rateof delistings has increased. Elements on both sides of the conserva- The Borax Lake Chub chub is endemic to the Downloaded by [Oregon State University] at 14:25 29 November 2011 geothermally-heatedwaters of Borax Lake and adjacent wetlands in Oregon's Alvord Basin tion debatehavesoughtto increase the numberof delisted species. During the Clinton Administration, Interior Secretary Babbitt (Williams and Bond 1980). The chub was listed believedthat the USFWS'sabilityto delistspecies as endangeredin 1980 by emergencyrule and because of recoverywasa clearindicationthat the again as endangered by final rule in 1982 ESA was a success. During this period, USFWS (USFWS 1982). At the time of listings,the priexpediteddelistingefforts,includingdevelopment marythreatsto the species consisted of potential of lists of speciesthat might warrant delisting impacts from geothermal energy development because of recovery(Benderet al. 1998).As Rohlf and diversionof the lake'soutflowsby alteration (2004) pointedout in a recentreviewof Section4 of the shorelinecrusts.Although no recovery of the ESA, federalagencies have both political team ever wasformedfor this species,a recovery incentive and institutional desire to find successin plan wascompletedin 1987 that calledfor prothe ESA bypointingto recoveredspecies that may be delisted.Of course,thosethat opposethe ESA tection of the Borax Lake ecosystemthrough are equally glad to see fewer speciesprotected acquisitionof key private lands, protectionof underthe act'sprovisions, butfor differentreasons. subsurfaceand surfacewaters,controlson access, Amongthe species that mightwarrantcontem- removal of livestock grazing, monitoring, and porary delistingis the Borax Lake chub (Gi/a other recoveryactions(USFWS 1987). The BoraxLakechubexistsasa singlepopulaboraxobius), anendangered species inhabiting a small tion that mostlikely hasbeenmaintainedwithin hot-spring ecosystem in southeastern Oregon.The restricted habitatoccupied bythe species recently has its historicrange of natural variability,and an beenacquired by a conservation groupandsurround- increase in abundance is not a factor in successful ingpubliclandhasreceived additional protections. In recovery.Recovery, in this instance, is based 2003, we conducteda reviewof the conservation sta- entirelyon habitat integrity,includingprotection tusof the BoraxLake chubto developa scientific of springaquifers,and the avoidanceof nonnaconsensus regarding the listingstatusandfuturecon- tive speciesintroductions. BoraxLakeisa spring-fed ecosystemin Oregon's AlvordDesertand, along with surroundingpools and marshes,the sole habitatfor the endangered Borax Lake chub. servation needs of that species. The purposes of this articleare to report on the resultsof our evaluation of the Borax Lake chub,discuss implications of ourfindingforthevulnerabilityof otherspecies of restricted range,andto provide recommendations for statusreviews for endemic specieslisted pursuant to theESA.We also offer our opinion regarding appropriate criteria for measuringthe successof the ESA itself. Managementof endangered and threatened fishes, including their recovery anddelisting, are criticaltopicsto fisheries biologists. We hopethis article stimulates further debate on measures of successfor the ESA and understanding of the • appropriate role of • delisting. ::,• .......... June 2005 I www.fisheries.org I Fisheries 25 Numerousrecoverymeasures havebeenimplemented during the past two decadesto secure habitat for the species.In 1983, the Bureauof Land Management(BLM) designated the public lands surroundingBorax Lake as an Area of Critical Environmental Concern. The Nature Conservancy (TNC) leasedtwo 160-acreprivate landparcels,onesurrounding BoraxLakeandthe otherimmediatelyto the north, in 1983andpurchasedthem outright in 1993, therebybringing all landsdesignated ascritical habitat into public or conservationownership.With the acquisition by TNC, livestockgrazingceased.Passage of the and (4) convening of a 16-memberscientific panel to reviewfindingsfrom the recoveryplan, habitat, and listingfactorreviews.The panelists werescientiststhat had workedpreviouslyon the speciesand its habitat, agencybiologistswith managementresponsibility for the species,and other scientistswith extensive knowledge of desertspringsystems in westernNorth America. Panelistswere asked,usingtheir best scientific judgmenton issuesrather than agencypositions, to developa consensus on listingstatus,management, and monitoring. The expert panel concludedthat substantial progress hasbeen madetowardsrecoveryof the Borax Lake chub, but that despitethis progress, threats to the speciesand ecosystemremain. Downloaded by [Oregon State University] at 14:25 29 November 2011 SteensMotretain Cooperative Managementand Protection Act of 2000 withdrew public lands from mineral and geothermal development within a majorityof the Alvord Basin,including Results of the status review are summarized in the Alvord Table 1. Summaryof status reviewfindings for the Borax Lakechub.Forrecovery plan implementation review, recovery subtasks were scored on a scale of 0•4. 0 = no implementation 1 = minorimplementation 2 = approximately half implemented 3 = mostlyimplemented 4 = fullyimplemented Known Geothermal Resource Area Table 1. Threats that had been eliminated and Borax Lake. included the alteration With removal of many of the significant threatsfacingthe BoraxLakechub,the U.S. Fish and Wildlife Servicebeganto examineits feasibility for reclassification(R. White, USFWS, pers.comm.).The BoraxLake chubfrequentlyis citedby USFWS asbeing"on the brink of recovery" (Motivans and Balis-Larsen2003) and is rated by that agencyas having achieveda relatively high percentage of recovery implementation (51-75%; USFWS 2003). In flows, livestockgrazing,and geothermalenergy development on public lands. The primary remainingthreatswere increasinghabitat degra- 2003, two of the authors conducted a status review of the Borax Lake chub to determine whethera changein listingstatuswaswarranted andto reviewfuturemanagementandmonitoring needsfor the species(Williams and Macdonald 2003). The status review consistedof four com- ponents: (1) review of recovery plan implementation,(2) field investigations at Borax Lake to determinecurrent statusof the species and habitat, (3) review of the five listingfactors from Section 4 of the EndangeredSpeciesAct, of lake shoreline and out- dation associated with recreational use and the increasingpotential of nonnative speciesintroduction. Exotic goldfish (Carassiusauratus) recentlyhave been introducedinto Mann Lake just to the north of Borax Lake (Tim Walters, Oregon Department of Fish and Wildlife, pers. comm.). Both recreationand introducedspecies receivedminor attention in the 1987 recovery plan. Borax Lake is located in a remote and sparsely-populated area,but one that is increasingly usedby a public seekingopportunitiesfor solitude,wildlife observation,and open space. The panelbelievedthat becausethe rangeof the BoraxLake chub is restrictedto singlegeologically fragile site, the speciesis vulnerable to catastrophic lossdespiteexistingprotection.The panelalsonotedthe importanceof frequentmonitoring to detect and move to extirpate RecoveryPlan Implementation Task1: Securelandand water rights.Averagesubtaskscore= 3.7. Task2: RestoreLowerBoraxLake,smallponds,and interveningmarshes.Averagesubtaskscore= 4.0. Task3: ProtectBoraxLakeecosystem.Averagesubtaskscore= 2.7. Task4: Monitorstatusof ecosystem. Averagesubtaskscore= 2.3. Task5: Encouragesupportof recoverythroughpublicawareness.Averagesubtaskscore= 3.5. Field Investigations Habitatand chubpopulationappearedin goodconditionandwithinexpectedrangeof variationobserved historically. Significantrecreationaluse(off-roadvehicleuse,camping,disturbance of lakesubstrates from wading)was noted. Review of 5 ListingFactors 1. Presentor threateneddestruction, modification, or curtailment of its habitator range. 1982:threatsconsisted of chippingof crustsaroundshoreline,diversion of outflows, development of geothermalresource, and potentialdevelopment of recreation facility. 2003: threatsconsistof recreational useand potentialwater developmenton privatelands. 2. Overutilization for commercial, sporting,scientificor educationalpurposes. 1982, 2003: no threats for this factor. 3. Disease or predation.1982:no threatsfor thisfactor.2003: potentialintroduction of nonnative species. 4. Inadequacy of existingregulations. 1982: no threatsfor thisfactor.2003: no threatsfor thisfactor. 5. Othernaturalor manmadefactorsaffectingitscontinuedexistence. 1982:no threatsfor thisfactor.2003: because of restricted range,species vulnerable to disturbance event. 26 Fisheries I www.fisheries.org I vol 30 no 6 Downloaded by [Oregon State University] at 14:25 29 November 2011 introducedspeciesandto be ableto act quicklyin the face of other new threats.No changein listing statuswasrecommended althoughthe expert panelconcludedreclassification from endangered to threatenedcould be appropriatein the near futuredependingprimarilyupon implementation of a regularmonitoringprogram.The panel further concludedthat "maintainingthe BoraxLake chub on the list of Endangeredand Threatened Wildlife and Plantsaffordsthe greatestlikelihood that sufficientscientificand agencyattentionwill alligatorandperegrine falcon.Fivefisheshavebeen removedfrom the list of threatenedand endangered species, fourbecause of theirextinction(Tecopapupfish [Cyprinodon nevadensis calidae],longjawcisco [Coregonus alpenae], bluepike[St/zosted/on vitreum glau. cum],andAmistadgambusia [Gambusia amistadensis]) and one becauseof taxonomicrevision(Umpqua River form of coastalcutthroattrout,Oncorhynchus clarkiclarki).No fisheshave beendelistedbecause of recovery. Althoughit isdifficultto generalize aboutthe characteristics of listedspecies that makegoodcandibe focused on Borax Lake such that if habitat datesforrecovery, it seems clearthat species with the suiteof characters maymorereadilyrespond integrity is compromised,correctiveaction will following to recovery efforts: (1) habitatrequirements aremore be timelyenoughto savethe species." generalthan specific,(2) qualityhabitat remains Delisting and Vulnerability of withinhistoricrange,and (3) existingthreatfactors, Endemic Fishes suchasoverharvest, maybe easilyregulated. Simply species oftenfacedthreatsthat were Given the plethoraof possiblecausesof popu- stated,recovered to address throughavailable regulatory channels lation endangerment,determiningvulnerability easier of speciesto extinctioneventsis difficult.Many (AbbittandScott2001).On the otherhand,species habitatsand/orsmaller ranges maybe factorsare relevant, includinga species'habitat fromspecialized more vulnerable to loss (Terborgh 1974; Deacon and requirements, populationsize,and dispersalabiliMinckley 1991). In a review of the conservation status ties (Tilman et al. 1994; Driscoll 2004). Furthermore,a searchfor explanationsof status changesin many lesser-knownspecieslisted as endangeredor threatenedoften is hinderedby our lack of knowledgeof their basiclife history and habitat requirements.Nonetheless,certain factorscommonto manyendangeredspeciesare known to increase the likelihood of their extinc- tion. Thesefactorsincludesmallpopulationsize (SouIt 1983;Gilpin and SouIt 1986), restriction to a smallgeographic area(Lovejoyet al. 1986), dependenceupon a specific rare habitat type (Terborgh1974), and inability to move away from increasingsources of stressor habitat degradation (Diamond 1975). Endemicfisheswith a highly restrictedrange are particularlyvulnerableto extinctionbecause they occuras a singleor low numberof populations, dependupon a specifichabitat type, and have low tolerance for habitat modification. Endemicfishesmay be commonin the limited areaswherethey occurbut oftenhave rigid habitat requirements. These endemic species therefore,becomehighly vulnerableto habitat change or invasion of nonnative species (Minckley and Deacon 1968; Terborgh 1974). The vastmajorityof recentU.S. extinctionshave been in specieswith restrictedranges,including freshwater musselsof southeastern rivers, and plants and terrestrialinvertebratesof Hawaiian forests(Sucklinget al. 2004). In their review of westernfish conservation,Deaconand Minckley (1991) concludedthat the restricteddistributions and small population sizes of many springdwellingfishesdictated their virtual permanent statusasendangeredor threatened. Of the 15species thathavebeendelisted because of recovery, mostarewide-ranging, suchastheAmerican June 2005 I www. fisheries.org I Fisheries Jackrabbit Springin Ash of aquaticspeciesin the Great Basin,Sada and Meadows,Nevada,provides Vinyard(2002) foundthat dedinesweregreatest in habitatfor the endangered the mostnarrowly distributed andvulnerable popula- AshMeadowspupfishand tions.According to theiranalysis, all extincttaxaand AshMeadowsspeckled osculus mosttaxasuffering majordedines(68%) hadfewer dace(RhinichthJ/s nevadensis). Othernearby thanfivesmallpopulations. springsprovidehabitatfor A reportby Benderet al. (1998)listed22 species the endangeredDevilsHole considered likelycandidates by USFWSfor delisting pupfish(Cyprinodon andwarmsprings or redassification becauseof increased protection, diabolis) pupfish(C nevadensis includedthreefishes:tidewatergoby(Eucyclogobius Despite newberryi),Ash Meadows pupfish (Cyprinodonpectoralis). designation of the springs nevc•lensismionectes),and Pahrump poolfish asprotectedareas(Ash (Empe•ch•hys /atos).The tidewatergoby is more Meadows National Wildlife broadlyranging,but the Ash Meadows pupfishand Refugeanddisjunctportion Pahmmppoolfish arebothspring-dwelling fishes with of DeathValleyNational restricted rangesthat are similarto the BoraxLake Park),habitatsand fishes remain vulnerable. 27 Downloaded by [Oregon State University] at 14:25 29 November 2011 in ensuringthe continuedexistence of chubin termsof vulnerability. The AshMeadows pupfish andthree ESA hasbeensuccessful otherlistedfishesareendemicto springs in the Ash Meadows area the taxa it protects. Delisting of spring-dwelling fisheswith restrictedranges butremainvulnerable to catastrophic lossbecause ofintroductions of with considerable cautionbecause of their nonnative species and/ormodification to subsurface aquifers. These shouldbe approached andbiologicalvulnerabilityandtheir ability threats persist despite protective management of landaround surface inherentecological protectingmanylesser-known and spring areas. Therecovery planforAshMeadows species listsprotec- to serveasumbrellaspecies Althoughthe BoraxLakechubhasa higher tionof aquifers, eradication of nonnativespecies, andrestoration of unlistedorganisms. than manylistedspecies, it appears to an naturalspring habitats asessential criteriathatmustbemetbefore rateof recoverysuccess fishesshouldbe considered for delistingor reclassification from expertpanelto be a poorcandidate for delistinglargelybecause dependenton endangered to threatened (USFWS1990).Recovery ofthePahmmp of its inherentvulnerabilityasan endemicspecies poolfish isdoubtful. Thisspecies hasbeeneliminated fromitssingle a specialized habitat.Ironically,because the ESA isa strongregand habitatprotection,removalof this spring historic habitatbutexists asan introduced population onthe ulatorylaw for species DesertWildlifeRange.Like the BoraxLakechub,thesespring- protectionthroughthedelistingprocess alsoremoves thepreemdwelling desert fishes arelikelyto needtheprotection afforded bythe inent tool for maintainingthe speciesin the long run. The naturallyrestrictedrangeof many endemicfishesmakestheir ESA in perpetuity. to thepointof delisting an admirable butlargelyunobCurrentprocedures forddistingspecies pursuant to Section4 of recovery goal.• theESAaresimilarto listing.That is,thestatus ofthespecies iscom- tainable paredtothefivelistingfactors contained in Section 4, andfidelisting is believedwan'anted by USFWS, a proposal is published in the Acknowledgments Federal Register notifying thepublicoftheproposed change andseekThe authorswouldlike to acknowledge ourfellowBoraxLake ingpubliccomments. We suggest thepanelreviewconducted forthe panelists: Chris Allen, Darren Brumback, MichaelCummings, BoraxLakechubmayprovide a suitable modelto evaluate theESA JosephFurnish,Mary Hanson,Kathy Hollar, Phil Pister,Pete status of endemic species, particularly thoselackingrecovery teams. Rissler,Dan Salzer,andTim Walters.The authorsalsowouldlike Forspecies withrecovery teams, theteamlikelycouldsubstitute for to acknowledge JoelE. Pageland two anonymous reviewersfor theexpertpanel.Regardless, a varietyof factors should bereviewed their comments on earlier versions of this article. Much of this in anydelisting process, including the implementation status of any workwascompleted whilethe seniorauthorwasat the Institute applicable recovery plansandcurrentstatusof subject populations for EnvironmentalStudiesat Southern Oregon University. andhabitats, in additionto an analysis of thefivelistingfactors. Fundingfor the listingstatus reviewof the BoraxLakechubwas providedby the U.S. FishandWildlifeService. Conclusions References The desireto delistspeciesis driven,at leastin part, by the Abbitt,R. J. F., andJ. M. Scott.2001.Examining differences between beliefthat recoveryof listedspecies isan indicatorof the success recoveredand decliningendangeredspecies.Conservation of the ESA. Butwith only 15 taxadellstedbecause of recoveryin Biology15(5):1274-1284. the historyof the ESA, success asmeasured by thisindicatoris Bean, M. J. 1983. The evolutionof nationalwildlifelaw (revised poor.Moreappropriate indicators wouldincludechanges in popandexpanded edition).Pmeger Publishers, NewYork. ulationtrendsof listedspecies andthe abilityof ESAprotections Bender,M., K. Day Boylan,and E. L. Smith.1998.Turningthe cornertowards recovery. Endangered Species Bulletin23(2-3):4to preventextinction.In itslatestbiennialreportto Congress on 9. recoveryof listedspecies, USFWS (2003) reportedthat population trendsfor39% of listedtaxawereeitherstableor increasing, Deacon,J. E., andW. L. Minckley.1991.Westernfishesandthe real world:the enigmaof "endangered species" revisited. Pages while 34% weredeclining,and 24% wereuncertain.Pursuantto 405-413in W. L. MinckleyandJ. E. Deacon,eds.Battleagainst this indicator,the ESA faresbetter. If preventingextinction is the criterion, an assessment of the success of the ESA is even extinction: native fish managementin the American West. Universityof ArizonaPress, Tucson. morepositive,with only 7 taxadellstedbecause of extinction. Diamond, J. M. 1975. The islanddilemma:lessonsof modern biGgeographical studiesfor the designof naturalpreserves. Biological Conservation 7:129-146. Doremus, H. 2000. Delisting endangered species: an aspirational and 1998 (Schwartz1999). Recent data from the Center for goal, not a realisticexpectation.The Environmental Law BiologicalDiversity(Sucklinget al. 2004) supports the valueof Reporter30:10434-10454. ESA protectionsin preventingextinction.An analysisof 114 Doremus,H., andJ. E. Pagel.2001.Why listingmaybe forever: extinctionsof U.S. speciessincethe ESA waspassedin 1973 perspectives ondellsting undertheU.S. Endangered Species Act. One studyestimated that basedon riskof extinctionalone,192 listedtaxawouldhavebeenexpected to goexunctbetween1973 found that 81% of extinction events involved taxa that were not Conservation Biology15(5)1258-1268. protectedby the ESA (19% werelisted).Sucklingand others Driscoll, D. A. 2004. Extinction and outbreaksaccompany fragmentation of a reptilecommunity. Ecological Applications (2004) believethatremovalof procedural delaysin listingspecies 14:220-240. pursuant to theESAandeliminationof thelistingbacklog would Gilpin,M. E., andM. E. Soul(-'. 1986.Minimumviablepopulations: haveresultedin increased protectionthat likelywouldhavepreprocesses of species extinction.Pages19-34in M. E. SoulS,ed. ventedmanyextinctions. Additionally,manyrarebutnon-listed Conservation biology:the scienceof scarcityand diversity. species occurwith listedspecies andmayreceiveprotectionthat Sinauer.Associates, Sunderland, Massachusetts. couldbe indirectlycreditedto the ESA. Regardless, the small Lovejoy,T. E., R. O. Bierregaard,Jr., A. B. Rylands,J. R. Malcolm,(2. E. Quintela,L. H. Harper, K. S. Brown,Jr., A. H. numberof extinctions of listedspecies suggests stronglythat the 28 Fisheries I www. fisheries.org I vol 30 no 6 Powell, G. V. N. Powell, H. O. R. Schubart,and M. B. Hays. Terborgh,J. 1974.Preservation of naturaldiversity:the problemof 1986. Edge and other effectsof isolationon Amazon forest extinctionpronespecies.BioScience24:715-722. fragments.Pages257-285 in M. E. SoulS, ed. Conservation Tilman, D., R. M. May, C. L. Lehman, and M. A. Nowak. 1994. biology:the scienceof scarcityanddiversity.SinauerAssociates, Habitat destruction and the extinction debt. Nature 371:65-66ß Sunderland,Massachusetts. USFWS (U.S. Fish and Wildlife Service).1982ßEndangered and Minckley,W. L., andJ. E. Deacon.1968.Southwestern fishesand threatenedwildlife and plants; endangeredstatusand critical the enigmaof "endangered species." Science159:1424-1433ß habitatfor BoraxLake chub (Gi/a boraxobius). FederalRegister Motivans,K., and M. Balls-Larsen.2003. Specieson the brink of Downloaded by [Oregon State University] at 14:25 29 November 2011 recovery.Endangered SpeciesBulletin28(4):10-11. Plater,Z. J. B. 2004. Endangered Species Act lessons over30 years, and the legacyof the snaildarter,a smallfish in a porkbarrel. 47 (193):43957-43963ß 1987ßRecoveryplan for the Borax Lake chub, Gi/a boraxobius. U.S. FishandWildlifeService,Portland,Oregon. Environmental Law 34:289-308. __. 1990. Recoveryplan for the endangered and threatened Rohlf, D. J. 2004. Section4 of the Endangered SpeciesAct: top ten species of AshMeadows, Nevada.UßS.FishandWildlifeService, issues for the next thirty years.Environmental Law34:483-553. Portland,Oregonß Sada,D. W., and G. L. Vinyard. 2002.Anthropogenicchangesin ß2003.Recoveryreportto Congress: FiscalYears1997-98and biogeography of Great Basinaquaticbiota. Pages277-293in R. 1999-2000.U.S. Fishand Wildlife Service,Washington,D.C. Hersbier,D. B. Madsen, and D. R. Currey, eds. Great Basin 2004a. Number of UßS. specieslistingsper calendaryear. aquaticsystems history.Smithsonian Contributionsto the Earth Available onlineat http://endangered.fws.gov/stats/List cy2002.PDE Sciences33. SmithsonianInstitutionPress,Washington,DßC. . 2004b.Threatenedand Endangered SpeciesSystemdellsted Schwartz,M. W. 1999.Choosingthe appropriate scaleof reserves for conservation. Annual Reviewof Ecologyand Systematics species report as of 02/02/2004. Available online at 30:83-108. http://ecos.fws.gov/tess_publicJTESSWebpageDelisted ?listings=0. SoulS,M. E. 1983ßWhat do we reallyknowaboutextinction?Pages Williams,J. E., andC. E. Bond.1980.Gi/aboraxoNus, a newspecies 111-124 in C. M. Schonewal&Cox, S. M. Chambers, B. MacBryde, andW. L. Thomas,eds.Geneticsandconservation: a referencefor managingwild animal and plant populations. Benjamin/CummingsPublishing Company, Menlo Park, of cyprinidfish from southeastern Oregonwith a comparisonto G. alvordensis Hubbsand Miller. Proceedings of the Biological Societyof Washington93:293-298. Williams, J. E., and C. A. Macdonald. 2003. A review of the California. conservation statusof the Borax Lake chub, an endangered Suckling,K., R. Slack, and B. Nowicki. 2004. Extinctionand the species.Unpublished report. Southern Oregon University, Endangered Species Act. Centerfor Biological Diversity, Tucson, Arizonaß June 2005 I vvww.fisheries.org I Fisheries Ashland. 29