Relationships between Asiatic black bear kills and depredation costs in Prefecture,

Oscar C. Huygens1'6, Frank T. van Manen2, Donald A. Martorello3'7, Hidetake Hayashi4, and Junichiro Ishida5

1ShinshuUniversity, Department of Biology, Facultyof Science, Matsumoto,390-8621, Japan 2U.S. GeologicalSurvey, SouthernAppalachian Field Branch,274 EllingtonPlant Sciences Building, Departmentof Forestry,Wildlife and Fisheries, Universityof Tennessee, Knoxville,TN 37996, USA 3Departmentof Forestry,Wildlife and Fisheries, Universityof Tennessee, 274 EllingtonPlant Sciences Building,Knoxville, TN 37996, USA 4Shinshu University,Department of EnvironmentalSciences, Facultyof Science, Matsumoto,390-8621, Japan 5ShinshuUniversity, Department of Economics, Matsumoto,390-8621, Japan

Abstract: Over 1,000 Asiatic black bears (Ursus thibetanus)are killed each year in Japanto control depredationactivity. Our objective was to determineif killing bears reduces depredationcosts. We focused our study on Nagano Prefecture,where 2,562 nuisance bears were reportedkilled and where reporteddepredation cost exceededY1,430 million between 1979 and 1999. We used mixed models with repeatedmeasures to determineif annualdepredation costs were associatedwith the numberof bears killed. Our data set included 15 years (1985-99) of kill and cost data for 122 municipaljurisdictions within 10 regions. We performedanalyses at the regionallevel based on combinedharvest and nuisance kill data,and at the municipallevel based only on nuisancekill data.We classifiedthe numberof kills into 3 classes (low, medium, high). Analyses were repeated using prior-yearkills to examine whether a possible time-lagexisted. Annualdepredation costs were positively associatedwith the kill dataat the regional level (F =5.51; 2, 72.3 df; P = 0.006) during the same year. However, we observed no associationbased on prior-yearkill data (F = 0.96; 2, 65.1 df; P = 0.390), suggesting that depredation costs and bear kills are a function of nuisance bear numbersrather than reflectinga causal relationship between the 2 measures.Nuisance bear numbersmay in turn be affected either by the availabilityof natural foods or by general population trends. At the municipal level, depredationcosts were not associatedwith the numberof nuisancebears killed duringthe same year (F= 1.36; 2,466 df; P =0.258) or the prioryear (F = 0.42; 2, 459 df; P = 0.656). Ourresults suggest that systematicallykilling Asiatic bearsmay not be an effective tool for mitigatingnuisance costs. In municipalitieswhere nuisancecosts remainhigh, we recommendthat alternative methods be testedfor theirefficacy in mitigatingcosts. Such methodsmay includepublic education, changing or removingfinancial incentives to kill bears,changing crop rotationsto crops that are not attractiveto bears in risk areas,promoting natural food production, using electric fences, and applyingaversive conditioningtechniques.

Key words: Asiatic black bear, depredation,Japan, Nagano Prefecture,nuisance kill, Ursus thibetanus

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In Japan, nuisance activities by Asiatic black bears humans (Azuma and Torii 1980; Furubayashiet al. include stripping bark from trees; raiding crops, 1980; Watanabe 1980; Hazumi 1994, 1999; Angeli orchards,apiaries, and fish farms;feeding from compost 2000). The primaryresponse to bear depredationis for heaps and garbage bins; and attacking livestock and hunters to set cage traps to capture and kill nuisance bears. Hunters legally sell the parts of bears they kill (Mills and Servheen 1991, 1994), and they usually Presentaddress: 7 Route de la Dame Jouanne,77760 receive monetarycompensation from municipal offices Larchant,France; [email protected] local 7Presentaddress: WashingtonDepartment of Fish and or agriculturalcooperatives for killing nuisance Wildlife, 600 Capitol Way North, Olympia,WA 98501- bears. During 1985-99, depredation levels remained 1091,USA high despite the killing of over 1,000 nuisance bears

197 198 BEAR KILLS AND DEPREDATION COSTS IN JAPAN * Huygens et al.

the machinery and metal industries, precision-machin- ery, and food-processing industry. The economic importance of agriculture has sharply decreased in recent years, and in 1994 agriculturerepresented 4.7% of the gross prefecturalproduct. Yet Nagano still has more farms(149,000) thanany otherprefecture in Japan. Asiatic black bears occur in approximately60% of the Prefecture(8,000 km2 of 13,585 km2; Fig. 1), and Nagano's humanpopulation (2.2 million) is concentrated in theremaining 40% of land.The Prefectureis dividedinto 122 municipaljurisdictions, which are grouped into 10 administrativeregions. In NaganoPrefecture, decisions to kill nuisance bears are made at the municipal level, as stipulated by a regulation signed by the prefectural governorin 1980 and reinforcedby an ordinancepassed by the prefecturalassembly in 1999 (Nagano Prefecture 1980, 1999). Between 1979 and 1999, average reported estimatesof beardepredation costs exceededY 68 million per year ($1 US - 115 Y in 1999) and numberof bears killed annuallyas nuisancesand as legal harvestaveraged 122 and 69, respectively (total of 4,002 bears; Nagano Prefecture1995; NaganoPrefecture, unpublished data). Fig. 1. Location of Nagano Prefecture, Japan. Shaded area represents 1993 distribution of Asiatic black bears (modified from Hazumi 1999). Methods No direct measure of depredation incidents was available.Therefore, we assumed that depredationcosts annually (Hanai 1990; Hazumi 1994, 1999). To our were an adequate measure of depredation levels. knowledge, the effectiveness of killing Asiatic black Depredation costs were the visual cost estimates of bears as a method to reduce depredationlevels in Japan orchard, tree and other has not been tested. Therefore,the of our crop, plantation, depredations objective study to the office the 122 was to determine if a exists between the reported prefectural by municipal relationship We obtainedkill and cost data number of bears killed and bear costs. We jurisdictions. depredation depredation for the 15 from 1985 to 1999 from the central tested 2 null (1) the numberof bears killed years hypotheses: office harvest and nuisance control is prefectural (Nagano Prefecture, Nagano City, annually through legal cost and nuisance kill data were not correlatedwith depredationcost, and (2) the number Japan). Depredation available for municipal and regional levels. However, of bears killed annuallyfor nuisance control only is not harvest data for the general hunting season (15 Nov to correlatedwith depredationcost. 14 Feb) were only available at the regional level. Therefore,for hypothesis 1 we summarizedcost and kill Study area (legal harvestand nuisancekill) data by region, whereas We focused our study in Nagano Prefecture, on we summarizedcost and kill (nuisancekill only) databy , Japan's largest island (Fig. 1). Nagano is municipalityto test hypothesis 2. landlocked and the climate is greatly influenced by For the analyses, we correctedcost datato accountfor seasonal monsoons. Rain is more common in the south inflation.However, inflationdata were not available for of the Prefecture(265 cm annually)than the east (88 cm all commodities,and the breakdownof the commodities annually).However, the patternis reversedin winterdue damaged by bears was available only for 1997-99. to changing seasonal winds: 10 m of snow is common in Therefore, we averaged available data to generate the north, whereas the south receives about 0.6 m of a consistent basket of commodities damaged by bears snow. Agriculturetraditionally has played an important each year. We used domestic wholesale prices of hinoki role in the prefecturaleconomy, though in recent times cypress (Chamaecyparis obtusa) for all trees because Nagano has diversified into various industries such as hinoki cypress representedthe majority of the cost of

Ursus 15(2):197-202 (2004) BEARKILLS AND DEPREDATIONCOSTS IN JAPAN * Huygens et al. 199 trees damaged by bears in plantations.Consumer price only) at the municipal level was 0.9 bears (SE = 0.05; indices were used for all other commodities. range = 0-33); annual depredation costs averaged We used mixed modeling procedureswith a repeated Y528,097 per municipality (SE = 56,035; range - measures design (Proc MIXED; SAS Institute2000) to 0-41,501,000). determine if annual depredationcosts were associated Parameterestimates for region indicated that depre- with the number of bears killed. We normalized all dation cost differedamong the 10 regions (F= 21.59; 9, depredationcost data by using log-transformations.We 27.7 df; P < 0.001) and, to a lesser degree, years (F= calculated the effective degrees of freedom for each 1.84; 14, 62.9 df; P = 0.051). That is, much of the model by using the Kenward-Roger approximation variabilityin bear depredationcosts was explained by (Kenward and Roger 1997). Because municipalities region, likely because some regions had consistently sometimes reportedno depredationkills in a given year, greaternuisance activity than others. Bear depredation we reduced bias due to zero entries by classifying the costs were positively associated with category of bear numberof bears killed as a categoricalvariable: low (0- kills (low, medium or high; F= 5.51; 2, 72.3 df; P = 1 bear killed), medium (2-5 bears killed), and high (>5 0.006), and the interaction terms indicated that these bears killed). For the regional-level analysis, we relationshipsvaried by region (F = 3.48; 14, 68.3 df; P changed these criteria to 0-10, 11-25, and >25 bears < 0.001) but not by year (F= 0.75; 22, 62.7 df; P = killed, respectively. Some regions and municipalities 0.773). The model based on prior-yearkill data did not had no reported depredation costs in some years, indicate any relationshipswith the numberof bear kills resulting in skewed cost distributions.Therefore, we (F = 0.96; 2, 65.1 df; P = 0.390) or its interactionwith excluded those observationsfrom analysis because we region or year. were primarily interested in examining relationships We found no evidence at the municipal level that with the numberof bearnuisance kills when depredation depredationcosts were associated with the number of damage actually occurred.For the first hypothesis, we nuisance bearskilled duringthe same year (F= 1.36; 2, used region as the experimentalunit and combinedlegal 466 df; P = 0.258) or the prioryear (F = 0.42; 2, 459 df; harvest and nuisance kills to examine associations of P =0.656). Similarly, no significant interactionswith depredationcosts with the kill data, region, year, and region or year were evident (all P > 0.283). Reported their interactions.Because informationwas collected on depredationcosts varied among the 10 regions (current- the same experimental units over 15 years, we used year kill: F = 2.69; 9, 156 df; P = 0.006; prior-yearkill: a repeated measures design. We tested the second F = 3.54; 9, 85 df; P = 0.001) and among years (current- hypothesis using repeated measures as well, treating year kill: F = 1.94; 14, 462 df; P = 0.021; prior-yearkill: municipalitieswithin regions as the experimentalunits. F - 2.68; 13, 459 df; P = 0.001). We modeled covariances using a combinationstruc- ture that specified both between-experimental unit effects and a correlationstructure within experimental Discussion units thatdecreases with increasingtime lag (Littellet al. The longitudinal data set we compiled for Nagano 1998). As with the regional analysis, we included Prefecture provided a unique opportunityto examine region, year, and interaction terms in the model. For whetherbear depredationcosts may be reducedthrough both the regional- and municipal-level analyses, we harvest management or targeted killing of nuisance accountedfor a possible time lag between killing bears bears. However, the data we used contained some and the effects on depredationcost by repeating our inaccuracies, which should be considered in the in- analyses with kill data from the previous year (i.e., 1- terpretationof our results. For example, we discovered year time lag; 1986-99 data only). several errors in the data we received from the Prefecture,and more errors may remain. Also, under- and over-reportingof harvested bears occurs (Hazumi Results 1992, Moll 1994), and our data do not include poach- During 1985-99, a mean of 16.4 bears were killed ing incidents, although they occur throughout Japan annually (legal harvest and nuisance kills) per region (Hazumi 1992, Moll 1994) and Nagano (Huygens et al. (SE =1.1; range= 1-73) and annual depredationcosts 2001, Huygens and Hayashi 2001). Inaccuracies also = averaged Y6,280,526 (SE 1,049,688; range = 0- may exist in depredationcost data. Visual depredation 83,040,000) per region. During that same period, the cost estimates are subjective, and crops may be more mean number of bears killed annually (nuisance kills valuable in some areas than others (e.g., timber versus

Ursus 15(2):197-202 (2004) 200 BEAR KILLSAND DEPREDATIONCOSTS IN JAPAN * Huygens et al. corn) and, as such, the same level of depredation(e.g., 1 for extended periods (> 1 month) near depredationsites bear-night) may result in different monetary losses. and along bear approach routes. Furthermore,areas Finally, landowners receive no compensation for bear where bears have been sighted and where they are damage, removing incentives to reportbear damage or thought to present a threatto human safety, even if no to accuratelyestimate costs. financial losses have been incurred (e.g., schools, Despite the existence of data inaccuracies,we believe houses, hotels, garbage disposal sites), may be trapped that our observationsregarding the associationsbetween for extended periods as well. The killing of non-target depredation costs and the number of bear kills are bears and bears that do not generate monetary losses reliable. For example, even if the harvest data were would not directly affect depredationcosts, which may somewhat under- or over-reported,the results would explain why we failed to find significant associations have been similarbecause we categorizedthe kill datain between depredation costs and nuisance kills at the 3 classes. Furthermore,different definitions of those 3 municipal level. kill categories did not distinctly change the model parameters.Effects due to any inaccuraciesamong the depredationcost datalikely were limited as well because Managementimplications our goal was to examine associations, ratherthan pre- Local factors likely play an important role in dicting depredationcosts. Also, we have no reason to depredationincidents, including agricultural and forestry believe that the degree of inaccuracyin the reportingof practices, availability of natural bear foods, landscape depredation costs differed substantially among years, settings, changes in land use practices, local bear den- regions, or municipalities. sities, and effects of developments(such as golf courses, The regional kill data included both harvest and second homes, and hotels). Unique local conditions nuisance kills, with harvest kills typically representing require local coordinationof managementresponses to approximatelyone third of the total kill. Regionally, beardepredation. Such a system essentially is in place in annual depredation costs were associated with the Nagano Prefecture,but this method has not effectively number of Asiatic black bears killed through legal reducedconflicts to acceptablelevels. We speculatethat harvest and nuisance kills. Although this relationship the inaccessible mountains act as de facto refugia that varied somewhat among the 10 regions, the parameter are perpetual sources of nuisance bears, possibly estimates indicated that annual depredation costs in- reducing the effectiveness of reactive management creased, ratherthan decreased,with the total numberof responses, such as trapping and killing of nuisance kills during the same year. However, we did not find bears. Consequently,the image of bears in ruralareas of such a relationshipbased on prior-yearkill data, sug- the Prefectureremains largely negative (Huygens et al. gesting thathigher depredation costs at the regionallevel 2001). Methodsthat failed to reduce bear depredationto may simply reflect a greaternumber of nuisance bears, acceptable levels also led to landowner dissatisfaction which, in turn, would lead to more nuisance bear kills. and frustrationand generatednegative attitudestoward These results provide evidence that increased harvest bears and bear conservationin otherareas of Japan(Roy and nuisance kills do not necessarily result in reduced 1998) and in the U.S. (Ambrose and Sanders 1978, depredationcosts, either in the current or subsequent Brady and Maehr 1982). remains an year. We suggest that changes in all 3 measures (i.e., The reduction of bear depredation that depredationcost, nuisancekill, and harvest)may simply importantissue in Nagano Prefecture.We suggest to better be a consequence of temporalvariation in the availabil- currentmanagement plans should be adapted bear ity of natural foods and regional fluctuations in respond to locally varying levels of depredation. to populationabundance. We also propose that studies be conducted compare Our municipal analyses may provide additional the effectiveness of the currentmanagement approach evidence for this interpretation:targeted killing of bears with alternativeapproaches. Proactive approachesmay reactive man- that cause depredationwas not correlatedwith the cost be more successful in the long term than landowner and of depredationin the currentor subsequentyear. These agement responses. The lack of public to the results suggest that the currentsystem of killing bears interest has been cited as a major impediment after depredationevents may not help reduce depreda- evolution of bear managementin Japan (Kellert 1991, tion costs. When municipalitiesapprove the killing of Roy 1998, Hazumi 1999, Huygens et al. 2001). Farmers nuisance bears, non-target bears also may be killed in Nagano Prefectureoften are unconcernedor unaware because hunterscan set trapsto controlnuisance activity that planting crops near forests attractsbears and may

Ursus 15(2):197-202 (2004) BEAR KILLSAND DEPREDATIONCOSTS IN JAPAN * Huygens et al. 201

bears (n = 681, x = than other 100,000 20.6) municipalities (n = 872, x = 9.7), 90,000 suggesting that a substantial number C 80,000 of bears were killed to protect trees. ? 70,000 Yet from 1985 to 1999, damage to c trees seems to have increased more 8 60,000 0 thandamage to otherproperty (Fig. 2). 50,000 Supplemental feeding programs suc- " 40,000 cessfully reduced damage to conifer- 30,000 ous trees in the states of Washington and Oregon, USA (Ziegltrum 1998), a 20,000 and we suggest such a feeding pro- 10,000 gram be tested in Nagano as well. Finally, the legal market for bear - v- v- V v- v- parts and the compensation paid by ar Yer village offices or agriculturalcooper- atives provide hunters with financial incentives for the continued of 2. cost of Asiatic black bear to taking Fig. Depredation (?) damage crops bears Mills and and other property compared with bear damage to trees, Nagano (Servheen 1990; Prefecture, Japan, 1985-99. Costs were adjusted for inflation. Servheen 1991, 1994; Huygens et al. 2001). Consequently, landowner in- lead to nuisance activity. For example, farmers are centives to prc)tect their property may be diminished defensive about their right to plant sweet corn near because hunter;s offer an easy and inexpensive altera- forested areas in Nagano, and this leads to depredation tive (Huygens

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AZUMA,S., ANDH. TORII.1980. Impactof human activities on KENWARD,M.G., AND J.H. ROGER. 1997. Small sample survival of the Japanese black bear. InternationalConfer- inference for fixed effects from restricted maximum ence on Bear Research and Management4:71-79. likelihood. Biometrics 53:983-998. BRADY, J.R., AND D.S. MAEHR. 1982. A new method for LITTELL, R.C., P.R. HENRY, AND C.B. AMMERMAN. 1998. dealing with apiary-raidingblack bears. Proceedingsof the Statistical analysis of repeated measures data using SAS Annual Conferenceof the SoutheasternAssociation of Fish procedures.Journal of Animal Science 76:1216-1231. and Wildlife Agencies 36:571-577. MILLS,J.A., ANDC. SERVHEEN.1991. The Asian tradein bears FURUBAYASHIK., K. HIRAI,K. IKEDA,AND T. MIZUGUCHI.1980. and bear parts. World Wildlife Fund, Washington D.C., Relationships between occurrence of bear damage and USA. . 1994. The Asian tradein bears and bear clearcuttingin central Honshu, Japan. InternationalCon- ,AND and conservation recommendations. In- ference on Bear Research and Management4:81-84. parts: impacts ternationalConference on Bear Researchand GOTO,M. 2000. Asiatic black bear in Asahi village, Nagano Management Prefecture.Thesis, , Minami Minowa, 9(1):161-167. MOLL,J.P. 1994. Western influences on the managementof Japan. (In Japanese.) brown bears in , Japan. Thesis, University of HANAI,M. 1990. The status of Japanese black bear and few Montana,Missoula, Montana,USA. problems of its management. Eastern Asiatic Bear NAGANOPREFECTURE. 1980. Nagano Prefecture Regulation #7. Conference on Bear Biology and Their Status 1:44. (In Japanese.) (Abstractonly.) . 1995. Asian black bearmanagement and conservation HAZUMI,T. 1992. Current status and management of the plan. Nagano Prefectural Government. Nagano City, Asiatic black bear in Japan. World Wildlife Fund-Japan Nagano Prefecture,Japan. (In Japanese.) Science 1:293-333. (In Japanese.) Report . 1999. Nagano PrefectureOrdinance #46. (In Japa- . 1994. Status of black bear. International Japanese nese.) Conferenceon Bear Research and 9(1):145- Management RoY, M.M. 1998. Evolving human attitudesand management 148. policy in Japanese wildlife management:A case study of Status and of the Asiatic black .1999. management the Asiatic black bear (Ursus thibetanusjaponicus). Thesis, bear in 207-211 in C. S. Herrero, Japan.Pages Servheen, University of Montana,Missoula, Montana,USA. and B. Peyton, compilers. Bears. Status survey and SAS INSTITUTE.2000. SAS/STAT? User's Guide, Version 8. conservation action plan. IUCN (World Conservation SAS Institute,Cary, North Carolina,USA. Union), Gland, Switzerland,and Cambridge,U.K. SERVHEEN,C. 1990. The statusand conservationof the bearsof HUYGENS,O.C., ANDH. HAYASHI.1999. Using electric fences to the world. InternationalConference on Bear Research and reduceAsiatic black beardepredation in Nagano Prefecture, Management,Monograph Series 2. centralJapan. Wildlife Society Bulletin 27:959-964. WATANABE,H. 1980. Damage to conifers by the Japanese , AND . 2001. Asiatic black bear management black bear. InternationalConference on Bear Researchand plan in Nagano Prefecture,central Japan: a commentary. Management4:67-70. Biosphere Conservation3:115-129. ZIEGLTRUM, G.J. 1998. Animal Damage Control Program, , M. GOTO, S. IZUMIYAMA,H. HAYASHI, AND T. Annual Report 1998. Washington Forest Protection YOSHIDA.2001. Asiatic black bear conservationin Nagano Association, Olympia, Washington,USA. Prefecture, central Japan: problems and solutions. Bio- 1999 sphere Conservation3:97-106. Received: 17 October KELLERT,S.R. 1991. Japanese perceptions of wildlife. Accepted: 7 July 2004 ConservationBiology 5:297-308. Associate Editor: P. Genovesi

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