Effect of mast production on home range use of Japanese black bears

Kozakai, Chinatsu; Yamazaki, Koji; Nemoto, Yasuyuki; Nakajima, Ami; Koike, Shinsuke; S, Abe; Masaki, Takashi; Kaji, Koichi

doi:10.1002/jwmg.122

Cited by 100 publications

(60 citation statements)

References 26 publications

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“…Additionally, the changes in space use behavior in response to mast failures were similar to those of wild Asiatic black bears ( Ursus thibetanus ), which shifted their home ranges depending on whether mast production was poor or good [55]. However the patterns of fluctuating use of urban areas observed in this study contradicted results from a detailed and comprehensive study of black bear ecology in urban areas of Lake Tahoe, Nevada USA, where bears appeared to have an irreversible dependency on human foods [13].…”

Section: Discussionmentioning

confidence: 72%

Stochasticity in Natural Forage Production Affects Use of Urban Areas by Black Bears: Implications to Management of Human-Bear Conflicts

et al. 2014

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The rapid expansion of global urban development is increasing opportunities for wildlife to forage and become dependent on anthropogenic resources. Wildlife using urban areas are often perceived dichotomously as urban or not, with some individuals removed in the belief that dependency on anthropogenic resources is irreversible and can lead to increased human-wildlife conflict. For American black bears (Ursus americanus), little is known about the degree of bear urbanization and its ecological mechanisms to guide the management of human-bear conflicts. Using 6 years of GPS location and activity data from bears in Aspen, Colorado, USA, we evaluated the degree of bear urbanization and the factors that best explained its variations. We estimated space use, activity patterns, survival, and reproduction and modeled their relationship with ecological covariates related to bear characteristics and natural food availability. Space use and activity patterns were dependent on natural food availability (good or poor food years), where bears used higher human density areas and became more nocturnal in poor food years. Patterns were reversible, i.e., individuals using urban areas in poor food years used wildland areas in subsequent good food years. While reproductive output was similar across years, survival was lower in poor food years when bears used urban areas to a greater extent. Our findings suggest that bear use of urban areas is reversible and fluctuates with the availability of natural food resources, and that removal of urban individuals in times of food failures has the potential to negatively affect bear populations. Given that under current predictions urbanization is expected to increase by 11% across American black bear range, and that natural food failure years are expected to increase in frequency with global climate change, alternative methods of reducing urban human-bear conflict are required if the goal is to prevent urban areas from becoming population sinks.

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Section: Discussionmentioning

confidence: 72%

Stochasticity in Natural Forage Production Affects Use of Urban Areas by Black Bears: Implications to Management of Human-Bear Conflicts

et al. 2014

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“…, Kozakai et al. ). Smaller bears, especially females, are more likely to make late‐season migrations outside their normal ranges when food availability is high outside their home ranges and lower within them, because migration behaviour is costly (Noyce & Garshelis ).…”

Section: Hypothesis 4: Despotic Distributionmentioning

confidence: 99%

Ultimate and proximate mechanisms underlying the occurrence of bears close to human settlements: review and management implications

2012

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ABSTRACT1. Large carnivores (LCs), such as bears (Ursidae), are commonly believed to occur near human settlements because they have a learned tolerance of humans (human habituation) and because they associate humans with accessible highquality foods (food conditioning). Young bears and females with cubs are often overrepresented among 'problem' bears near settlements. 2. We review the mechanisms underlying the occurrence of brown and black bears (Ursus arctos, Ursus americanus, Ursus thibetanus) near settlements, and consider four hypotheses designed to separate ultimate and proximate mechanisms. 3. Increased occurrence of bears near people or settlements can be explained by (i) the human habituation hypothesis; increased use of human-derived foods can be explained by (ii) the food-conditioning hypothesis. However, both mechanisms are proximate, because they can only apply if bears have earlier experience of people and/or human-derived food. 4. A lack of human experience can explain the increased occurrence of younger bears near people or settlements: (iii) the naivety hypothesis. This is a proximate mechanism, because movements of naive bears are typically triggered by aggression and/or competition among conspecifics. 5. We conclude that the disproportionate occurrence of bears in certain sex, age and reproductive classes near people or settlements can only be explained by predation avoidance and/or interference competition, i.e. by (iv) the despotic distribution hypothesis. Therefore, a despotic distribution must be an ultimate mechanism causing the proximate mechanisms of habituation or conditioning. Thus, bears using settlements as predation refuges should not be considered 'unnatural' , but rather as exhibiting an adaptive behaviour, because of the despotic distribution among conspecifics. 6. Management of LCs includes attractant management, to counteract food conditioning, but failure to consider despotic behaviour among conspecifics may lead to treating only the symptom, e.g. habituation or conditioning. The ultimate cause of attraction to specific settlements may be identified by considering the type of bear involved; the occurrence of large solitary bears near settlements suggests attractive habitat or food shortage in remote areas, whereas subadults and females with cubs suggest lower-quality habitat.

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“…Although Q. crispula is the dominant species and a staple food resource for bears in this area (e.g. Kozakai et al ., ), bears showed little difference in preference for fruits among the three hard mast species in terms of eating fruits on tree. Thus, the effects of the factors affecting the detection probability of AFS in hard mast trees may be similar, despite interspecific differences in mast characteristics (e.g.…”

Section: Discussionmentioning

confidence: 83%

Detection of arboreal feeding signs by Asiatic black bears: effects of hard mast production at individual tree and regional scales

et al. 2018

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Arboreal feeding signs are among several field indicators of the use of tree crowns by the Asiatic black bear (Ursus thibetanus) to sit and eat fruit; however, it is unclear which factors influence this sign formation in hard mast species. Here, we investigated the influence of seed production by individual trees and at a regional scale by major hard mast species on the detection of arboreal feeding signs. For 7 years, we quantitatively assessed seed production by 374–481 trees each year of three dominant hard mast species (Quercus crispula, Quercus serrata and Castanea crenata) in the Ashio‐Nikko Mountains of central Japan and checked for the presence or absence of arboreal feeding signs in these trees. We estimated individual tree energy values and regional mast energy values across these three species and evaluated the influence of each factor on the detection probability of arboreal feeding signs. Arboreal feeding signs were more likely in individual trees with larger mast energy values and during poor mast years. There was no difference among species in the relative importance of individual tree energy or regional mast energy. Interaction of factors was also detected: the magnitude of the positive effect of individual tree energy on the detection of arboreal feeding signs was larger in poorer mast years, and the negative effect of regional mast energy was more conspicuous in the case of trees with greater mast energy. Thus, bears may maximize their feeding efficiency on hard mast in various ways, depending on regional mast availability; during poor mast years, bears are more likely to climb trees with higher individual tree energy values and leave arboreal feeding signs. Arboreal feeding signs cannot be used as an indicator of bear density unless both individual tree energy and regional mast energy values are monitored.

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Effect of mast production on home range use of Japanese black bears

Cited by 100 publications

References 26 publications

Stochasticity in Natural Forage Production Affects Use of Urban Areas by Black Bears: Implications to Management of Human-Bear Conflicts

Stochasticity in Natural Forage Production Affects Use of Urban Areas by Black Bears: Implications to Management of Human-Bear Conflicts

Ultimate and proximate mechanisms underlying the occurrence of bears close to human settlements: review and management implications

Detection of arboreal feeding signs by Asiatic black bears: effects of hard mast production at individual tree and regional scales

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