Chinatsu Kozakai

Effect of Mast Production on Home Range use of Japanese Black Bears

ABSTRACT n Although bears may expand their home ranges in times of low food availability, it is unclear what mechanisms directly affect home range extension in times of low mast production in Japanese forests. To clarify the relationship between home range utilization by Japanese black bears (Ursus thibetanus) and abundance and distribution of mast production, we collected data on habitat use from 13 bears (6 M and 7 F) fitted with Global Positioning System (GPS) collars equipped with activity sensors in the Ashio-Nikko Mountains on the eastern part of Honshu Island, Japan, during 2006–2008. We also collected data on mast production by 5 Fagaceae species. We categorized each fall as either poor (2006) or relatively-good (2007 and 2008) based on mast production. Bears used small patches in their large home ranges and the distances between core areas increased in the fall of 2006, when the mast of Japanese oak (Quercus crispula) were poorly distributed. Our findings suggest that localized patches of Japanese oak are the staple food for bears in our study area, even in poor mast years. However, in the fall of 2006, we also found that bears moved to lower elevations, relative to 2007 and 2008, in search of alternative foods (e.g., Konara oak [Q. serrata] and Japanese chestnut [Castanea crenata]), which were mostly at lower elevations and produced mast consistently over the study period. Our results suggest that dispersion and elevational distribution of mast-producing trees affect bear habitat use in fall, as well as amount of mast.

Frugivory of carnivores and seed dispersal of fleshy fruits in cool-temperate deciduous forests

Five members of the order Carnivora in the cool-temperate deciduous forests of Japan consume the fruits of trees, and they are potential dispersers of the seeds of fleshy-fruited plants. We studied the frugivory of the Asiatic black bear, Japanese marten, badger, red fox, and raccoon dog in cool-temperate deciduous forest of central Japan. From May 2003 to April 2005, a total of 377 fecal samples of the five carnivores (bears, 91; martens, 158; badgers, 45; foxes, 36; and raccoon dogs, 47) were sampled to determine the presence and frequency of occurrence of seeds. Seeds from 17 plant species, representing about 50% of the fleshy-fruited plants occurring in the study forest, were recovered from the carnivore fecal samples. Large numbers (9–10,256) of seeds were present in those feces. Almost all the seeds of fleshy fruits retrieved from the fecal samples were undamaged whereas no intact acorns or nuts were recovered. These findings suggest that all five carnivores can act as seed dispersers for some fleshy-fruited plants in cool-temperate deciduous forest.

A Preliminary Evaluation of Activity-Sensing GPS Collars for Estimating Daily Activity Patterns of Japanese Black Bears

Abstract The Japanese black bear (Ursus thibetanus japonicus) is a forest-dwelling species and can be very difficult to observe directly in most of its habitats. Therefore, as a research tool to evaluate activity patterns and time budgets, we fitted GPS radiocollars with activity sensors on 4 Japanese black bears, 2 males and 2 females, during 2003–06 in the Ashio Mountains, which have open habitats. Through comparison to observations from a video camera with activity sensor values, we categorized activities as either resting (inactive) or feeding with short distance movements (active). Bears were mostly diurnal, although they were increasingly active at dusk. Mean time inactive was 66%, including considerable inactive time during daylight. Time active ranged from 22–48%, depending on the bear. For one adult female, diel active time during a year she was solitary declined significantly from the previous year in which she had nursed 2 yearlings. For one sub-adult male, diel active time decreased significantly with increasing age. Although more research is needed to relate activity values to age and sex in a variety of habitats, we conclude that GPS collars with a built-in activity sensor can be an effective research tool for clarifying the living habits of Japanese black bears. If future studies can further refine relationships between sensor values and activity categories, diel energy costs for Japanese black bears may also be estimated.

Myrmecophagy of Japanese black bears in the grasslands of the Ashio area, Nikko National Park, Japan

Abstract Ants are an important food resource for most of bear species. During the summer, Japanese black bears (Ursus thibetanus japonicus) use grasslands in the ∼60 km2 Ashio area as an ant feeding site. We studied levels of myrmecophagy using GPS locations and activity sensor information along with direct observations of 2 bears during 2004 and 2005. We measured species composition, biomass, and nutrient contents of the ants and estimated use of ants through bear scat analysis. Both the number of ant species and biomass were higher in Ashio than in the adjacent forest areas. We recorded 15 ant species, 9 of which were fed on by the bears. Lasius flavus and L. hayashi were most abundant species and the species used by bears most often. Bears spent 7–8 hours/day feeding on ants. We estimated that they potentially ate 50,000–60,000 mg (dry weight)/day of ants, whose energy content was around 180–300 kcal/d, insufficient to meet their basal and field metabolic needs. Bears may have used ants for essential amino acids that they are unable to produce themselves. Assuming bears come to Ashio specifically for ants, these grasslands are valuable for bears at a time when vegetative food resources are limited.

Effect of hard mast production on foraging and sex-specific behavior of the Asiatic black bear (Ursus thibetanus)

Abstract. n We studied the relationships between movement and foraging habits of the Asiatic black bear (Ursus thibetanus) and hard mast production of five tree species in cool temperate forest during 2006–2008. The purpose of this study was to test the hypothesis that low mast production affects sexual differences in bear behavior. We summarized the movement pattern of 13 bears in terms of minimum movement distance and cumulative movement distance of the movement path followed during 24 hour. Masting of Quercus crispula acorns was low in 2006, high in 2007 and moderate in 2008. The dominant food items found in bear scats were hard mast, especially Quercus acorns. The percentage of Quercus acorns in the food items in scats was higher in 2007 than in 2006 and 2008. Movement distance of males and females increased in the low mast year. However, the increase of movement distance of females was larger than that of males. Thus, masting influenced the behavior of females more strongly than males. Our results indicated that low mast production changed the food habits and the size of the home range of bears, especially of females.

Examination of captive Japanese black bear activity using activity sensors

92008 ?? 33 1159 Received 18.12.2007 ; a cepted 19.2.2008 Copyright

Fluctuation of daily activity time budgets of Japanese black bears: relationship to sex, reproductive status, and hard-mast availability

Abstract We documented the fluctuation of daily time budgets in Japanese black bears (Ursus thibetanus japonicus) throughout the year using continuous day-to-day data from activity sensors integrated into global positioning system collars, during 2003–2009. We evaluated the influence of availability of food resources on daily active time of bears in conjunction with differences in sex and reproductive status of females (with or without offspring). The daily active time of bears fluctuated nonlinearly throughout the year. There were 3 turning points at which the activity level clearly changed from increasing to decreasing, or vice versa. Level of activity gradually increased in spring and reached a peak in July, then decreased and reached a trough in late August, and increased and reached a peak again in October. Males and females exhibited similar patterns of seasonal fluctuation in daily active time, although there were differences of activity levels between sexes during some periods. Dates of the 3 turning points did not differ between sexes, or among years. Seasonal variation in food availability may explain the timings of the turning points, at least in part. In addition, yearly variation in food resources, especially hard mast, may have affected the increasing and decreasing pattern of daily active time during autumn. Our results suggest that evaluating activity level based on pooled data without examining differences within a season (or month), and differences in year, sex, and reproductive status may result in misinterpretation.

Spatial and elevational variation in fruiting phenology of a deciduous oak (Quercus crispula) and its effect on foraging behavior of the Asiatic black bear (Ursus thibetanus)

In habitats with elevational gradients, differences in the fruiting phenology of a single key food resource may affect the feeding behavior of an animal. The objectives of the present study were to assess (1) whether or not fruiting phenology and characteristics of Quercus crispula acorns differed with changes in altitude (900–1,400xa0m asl) and area; (2) when bears foraged acorns in relation to their phenological development; and (3) where bears engaged in acorn foraging behavior with respect to acorn phenology. No difference in the fruiting phenology of acorns at various altitudes and locations was found, with the exception of changes in color and abscission period. Acorn abscission period occurred later at a site with an elevation of 1,200xa0m in Tochigi and at another with an elevation of 1,400xa0m in Gunma, making the available energy of acorns in the tree canopy (AET) greater and available for a longer time period at those two sites. Foraging of acorns by bears was observed at sites of moderate to high altitude between late September and mid-October. A threshold date when acorns became suitable for foraging by bears could not be identified, as the size and nutritional value of acorns increased continuously. Foraging activity of bears observed at moderate and high altitude sites corresponded with locations where AET was available in greater amounts and for a longer period of time for some sites; however, the small sample size precluded accurate assessment.

Seed removal and survival in Asiatic black bear Ursus thibetanus faeces: effect of rodents as secondary seed dispersers

We investigated the fate of seeds of five tree species hill cherry Prunus jamasakura, Korean hill cherry P. verecunda, Japanese bird cherry P. grayana, giant dogwood Swida controversa and crimson glory vine Vitis coignetiae in the faeces of the Asiatic black bear Ursus thibetanus in a temperate forest in central Japan. Clarifying the fate of seeds dispersed by endozoochorous seed dispersers will enhance assessments of their roles as primary seed dispersers. We established several experimental treatments in the field. Each faeces sample was covered by cages with different mesh sizes which limited accessibility by animals (NM: no mesh, SM: 1 mm mesh and MM: 10 mm mesh). We examined whether seed removal varied among tree species and between mesh-size treatments from 2004 to 2007 (N = 625 samples). We set up an automatic camera trap 1.5 m above the ground at all NM treatments. In the NM treatments, the number of seeds of all tree species decreased immediately after the faeces were set. In June of the following year, < 1% of the seeds from any species remained in the vicinity of the faeces. However, we found 3.0-13.2% intact seeds of all species in the soil below the faeces, as well as within a 10-m radius around the faeces. In the NM treatments, most seed removals were observed within four days after the faeces were set. For all tree species in the MM treatment, most of the seeds were present on the surface of the soil, and 1-2% of the seeds germinated at the location where faeces were set. In the SM treatment, none of the seeds from any of the tree species disappeared and germinated. We took a total of 415 photographs at the NM sites, 97.8% of which were of rodents either holding or eating seeds. Many of the seeds contained in the bear faeces were removed and eaten by rodents. However, 2.1-5.1% of the seeds survived and germinated, which implies that rodents may also act as secondary seed dispersers.

Insectivory by Five Sympatric Carnivores in Cool-Temperate Deciduous Forests

Abstract. n We studied insectivory by five carnivores—the Asiatic black bear (Ursus thibetanus), Japanese marten (Martes melampus), Japanese badger (Meles meles), red fox (Vulpes vulpes), and raccoon dog (Nyctereutes procyonoides)—in a cool-temperate deciduous forest in Japan. From May 2003 to April 2005, we assayed 373 fecal samples (91 from bear, 158 from marten, 43 from badger, 36 from fox, and 45 from raccoon dog) for insects. Each carnivore species consumed a variety of insect species, some preferentially. Bears preferred colonial insects like ants and wasps; martens ate a variety of forest insects, such as ground beetles and arboreal insects; badgers preferred forest ground beetles; foxes ate ground beetles and grassland insects; and raccoon dogs ate a variety of species. Dietary preferences may reflect the feeding strategy, behavior, or habitat preference of each carnivore species. Based on the habitat preferences of the insects, we could assign carnivores to particular microhabitats: bears and martens used forest in three dimensions, badgers inhabited forest in two dimensions, foxes used grassland and forest in two dimensions, and raccoon dogs inhabited grassland and forest in three dimensions. Identification of insects in feces may provide information on the dietary and habitat preferences of these carnivores.