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Bear Reintroductions:Lessons and Challenges

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Bear Reintroductions:Lessons and Challenges BEAR REINTRODUCTIONS:LESSONS AND CHALLENGES INVITEDPAPER JOSEPHD. CLARK,U.S. GeologicalSurvey, Southern Appalachian Field Laboratory, 274 EllingtonPlant Sciences Building, Universityof Tennessee, Knoxville,TN 37996, USA, email: [email protected] DJUROHUBER, Department of Biology,Veterinary Faculty University of Zagreb,Heinzelova 55, 10000 Zagreb,Croatia, email: [email protected] CHRISTOPHERSERVHEEN, U.S. Fish and WildlifeService, UniversityHall, Room 309, Universityof Montana,Missoula, MT 59812, USA, email: [email protected] Abstract: Reintroductionis defined as an attemptto establisha species in an areathat was once partof its historicalrange, but from which it has been extirpatedor become extinct. Historically,one of the most successfulprograms was the reintroductionof 254 Americanblack bears (Ursus americanus) from Minnesotato the InteriorHighlands of Arkansasin the 1960s; that populationhas grown to >2,500 today. More recent efforts have involved fewer but bettermonitored animals and have sometimes employed techniquesto improve site fidelity and survival. In Pennsylvania,for example, pregnantfemale Americanblack bears were successfully translocatedfrom winterdens, the premisebeing thatthe adultfemales would be less likely to returnbecause of the presenceof young cubs. That winter-releasetechnique was comparedto summertrapping and release in Tennessee;winter releases resultedin greatersurvival and reducedpost-release movements. Homing has not been a problemfor small numbersof brownbears (Ursus arctos) reintroducedto the Cabinet-Yaakecosystem in Montanaand Idaho and to the mountainsof Austria and France. Reintroductionsuccess appears to be correlatedwith translocationdistance and is greaterfor subadultsand females. As with any small population,reintroduced bear populationsare susceptibleto environmentalvariation and stochasticdemographic and genetic processes. Althoughmanagers have focused on these biological barriers,sociopolitical impedimentsto bear reintroductionare more difficult to overcome. Poor public acceptanceand understandingof bears are the main reasons some reintroductionprograms have been derailed. Consequently,the public should be involved in the reintroduction process from the outset; overcoming negative public perceptionsabout bear reintroductionwill be our greatestchallenge. Ursus 13:335-345 (2002) Key words: bear,reestablishment, reintroduction, restoration, translocation, Ursus americanus, Ursus arctos Termsto describe animaltranslocations are often con- patchesfollowing periodiclocal extinctions(Levins 1970, fused. The InternationalUnion for the Conservationof Hanski 1996). Bears, however, may not be well adapted Nature (IUCN) ReintroductionSpecialist Groupdefines to exploit such habitats. Although the considerabledis- reintroductionas an attemptto establisha species (or lower persal capabilities of male black and brown bears have taxonomic unit) in an area that was once part of its his- been well documented(Kemp 1976, Youngand Ruff 1982, torical range, but from which it has been extirpatedor Schwartz and Franzmann1992, Blanchardand Knight become extinct (IUCN 1998). Reintroductionis some- 1995, Stratmanet al. 2001), thatbehavior is not typical of times called repatriation(Reinert 1991). When native all age and sex classes, and rateof populationspread cor- conspecifics already are present, reintroductionsare re- relates only weakly with mobility (Caughley 1977:69). ferred to as supplementationsor augmentations(IUCN Females of at least some bearspecies typicallydo not dis- 1998). Reintroductiondiffers conceptuallyfrom the re- perse and, thus, reside within a portionof their mother's lated methods of nuisance translocations,fostering, and home range(Schwartz and Franzmann 1992). Also, bears rehabilitationbecause the primaryobjectives of thosetech- have relatively low reproductiverates (Bunnell and Tait niques usually are not populationreestablishment. Al- 1981), a characteristicwhich limitspopulation growth and though the latter methods have been well documented naturalcolonization ability (Hanski 1991, Hastings1991). (e.g., Boyer and Brown 1988, Linnell et al. 1997, Stiver Consequently,bears should probablybe consideredpoor et al. 1997, Clark 1999), we discuss those methods only colonizers and reintroductionmay be necessary to expe- to the extentthat they relateto reintroductionas the IUCN dite this otherwise slow recolonizationprocess. it. defines Reintroductionis a costly and time-consumingenter- Reintroductionof bears has been the subject of much prise, with only about 11%of all species reintroductions renewed interest. The distributionand numbersof most resulting in viable populations(Beck et al. [1994] from bear species have been dramaticallyreduced and frag- Earhardt [1999]). In general, reintroductionsuccess is mentedbecause of habitatloss, overexploitation,or some enhancedin instances when there are a large numberof combinationof both (Servheen 1990). Yet, in many cases founders,low environmentalvariation, and access to refu- the causes of historical populationdeclines have been rec- gia, and for species with high genetic variability,a high tified; habitatshave recoveredin many areasand laws are rateof populationincrease with low varianceand low in- in place to preventoverexploitation. traspecific competition (Griffith et al. 1989). Unfortu- In the case of populationfragmentation, long-term per- nately, bears exhibit low population growth with high sistence on depends recolonization of vacant habitat variance,are subject to high environmentalvariation (e.g., 336 Ursus 13:2002 annual fluctuations in food production), and have low HISTORICALPROGRAMS genetic variability relative to their population size Few bear reintroductionefforts have occurred,fewer (Manlove et al. 1980, Wathenet al. 1985). Furthermore, have been successful,and fewer still have been adequately bearshave a stronghoming instinctand often travelgreat documented. Perhapsthe earliest programwas a 1933 distances (Beeman and Pelton 1976, Miller and Ballard Californiaeffort, where about 30 Americanblack bears 1982, Rogers 1987) and experience increased mortality were translocatedfrom Yosemite National Park to the following translocation(Rogers 1986, Fies et al. 1987, Angeles National Forest (D. Updike, CaliforniaDepart- Stiver 1991, Comly 1993, Riley et al. 1994, Blanchard ment of Fish and Game, Sacramento,California, USA, and Knight 1995). Thus, reintroductionin general, and personalcommunication, 2002; Table 1). Managersused bearreintroduction specifically, presents many challenges. a hard release, whereby animals were captured,trans- Our goals for this paper are to provide an overview of ported,and released without an acclimationperiod. Griz- bearreintroduction efforts worldwide, summarize the find- zly bearshad been extirpatedin 1922 from the areawhere ings, and offer guidancefor the future. the black bears were reintroduced.Although the Ameri- Table1. Characteristicsof bearreintroduction programs and eventualoutcomes. Abbreviations:NP = NationalPark, NF = National Forest, Am. = American, NWR= National WildlifeRefuge. Distance from capture Number Species and Source Release area site (km) re-leased Date reintroductionmethod Outcome Yosemite NP, Calif., Angeles NF, Calif. USA 350 -30 1930s Am. black bears, hard Success USAa release Cook County, Minn., Interior Highlands, 1,570 254 1958-68 Am. black bears, hard Success USAb Ark., USA release Cook County, Minn., Northern La., USA 2,030 161 Mid- Am. black bears, hard Unknown USAc 1960s release Failure Byelorussiad Bialowieza, Poland 300 >11 1938 Brown bears, soft release of captive bears Vienna, Austria (zoo)' Trentino, Italy 2 1959 Brown bears, soft release Failure of captive bears Zurich, Switzerland (zoo) Trentino, Italy 4 1969, Brown bears,hard release Failure and Este Castle, Italy 1974 of captive bears (zoo)' Northeast Penn., USAf Southeast Penn., USA 440 22 1977-84 Am. black bears, soft Success release with winter-den technique Unknown Shenandoah NP, Virginia, SoutheastVa., USA 298 43 1991 Am. black bears, hard USAg release of nuisance bears Croatia, Sloveniah Austria >400 3 1989-93 Brown bears, hard release Success Northern Montana, USA' CabinetMountains, 20-40 4 1990-94 Brown bears, hard release Pending Mont., USA Am. black soft Great Smoky Mountains Big South Fork,Tenn., 160 14 1996-97 bears, Pending den NP, Tenn., USAj USA release with winter technique and summer acclimation pens Sloveniah Central Pyrenees, 1600 3 1996-97 Brown bears, hard release Pending France Northern and southern Am. black bears, soft with winterden La., USAk Central La., USA 50-180 6 1998-01 release Pending technique hard release Slovenia' Alps, Italy -400 7 1999-01 Brown bears, Pending soft White River NWR, Ark., Felsenthal NWR, Ark., 160 10 2000-01 Am. black bears, Pending USAm USA release with winter den technique a 2002 D. Updike, CaliforniaDepartment of Fish and Game, Sacramento,California, USA, personalcommunication, b Smith and Clark 1994 c Taylor 1971 d Buchalczyk 1980 e Osti 1999 f Alt 1995 g Comly 1993 h D. Huber,University of Zagreb,Zagreb, Croatia,, unpublished data i Servheenet al. 1995 J Eastridgeand Clark2001 k D. Anderson,U.S. Fish and Wildlife Service, Tallulah,Louisiana, personal communication, 1999 1 P. Genovesi, InstitutoNazionale per la FaunaSelvatica, Ozzano Emilia, Italy, personalcommunication, 2001 m B. Wear,University of Tennessee, Knoxville, Tennessee, USA, personalcommunication, 2001 BEAR REINTRODUCTION* Clark et al. 337 can black bearpopulation size today is unknown,the
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