Kengo Furubayashi

Fruit phenology of Prunus jamasakura and the feeding habit of the Asiatic black bear as a seed disperser

We investigated the relationship between the fruit phenology of Prunus jamasakura and the fruit-feeding period of the Asiatic black bear (Ursus thibetanus). The purposes of this study were to determine (1) when bears feed on the fruit of P. jamasakura in relation to phenology; (2) whether ingestion damages seeds; and (3) how ingestion influences seed germination. We assessed the relationship between the phenology of fruit maturation (size, sugar concentration, color, persistence, and germination percentage) and the feeding period of bears in the field, as judged from bear shelves and claw marks. We also compared the germination percentage of seeds ingested by captive bears with that of uningested. Bears fed on the fruit from days 50 to 66 after flowering, when most of the fruits were on the tree and became large, the germination percentage of seeds increased, and the sugar concentration became high. Bears fed only on mature fruits and so obtained high-quality nutrients. Germination tests showed that ingestion of fruits by the bears caused no physical damage to the seeds. Ingested seeds did not show a significant difference in germination percentage from seeds, whose pulp was artificially removed. These results indicate that bears are potentially effective dispersers from a qualitative perspective and, to some extent, from a quantitative perspective.

The impact of habitat fragmentation on genetic structure of the Japanese sika deer (Cervus nippon) in southern Kantoh, revealed by mitochondrial D-loop sequences

In southern Kantoh, Japanese sika deer (Cervus nippon) are distributed discontinuously due to large urban areas and developed road networks. To assess the impact of habitat fragmentation on sika deer subpopulations, we examined mitochondrial D-loop sequences from 435 individuals throughout southern Kantoh. About 13 haplotypes were detected, and their distributions revealed spatial genetic structure. Significant genetic differentiation was observed among seven of eight subpopulations. We found no significant correlation between pairwise FST and geographical distance among subpopulations. Genetic diversity indices suggested that seven of eight subpopulations had probably experienced population bottlenecks in the recent past. Therefore, and in the light of the results of a nested clade analysis of these haplotypes, we conclude that recent fluctuations in population size and the interruption of gene flow due to past and present habitat fragmentation have played major roles influencing the spatial genetic structure of the sika deer population. This is the first evidence of spatial genetic population structure in the highly fragmented sika deer population in Honshu, Japan.

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.

Examination of captive Japanese black bear activity using activity sensors

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

Effect of Snow Cover on the Distribution of Non-migratory Sika Deer on the Top of Mt. Tanzawa, Japan

On the basis of 268 direct sika deer observations and 212 ratio locations of three individuals, the influence of snow on deer distribution was studied. During the period of snow absence or its shallow cover, the deer did not show any preferences towards slope aspect. However, when the snow coverage became deeper, the deer used westerly exposures (having shallower snow cover) more intensively. Later on, when the snow started to melt on the easterly slope aspects deer mostly used those exposures due to relatively abundant food resources.

Evaluation of GPS collar performance by stationary tests and fitting on free-ranging Japanese black bears

Abstract We evaluated the performance of two GPS collars as a tool for studying Japanese black bears (Ursus thibetanus japonicus) in the Kanto region, Japan. Collars were placed at five stationary points to test the effects of GPS antenna orientation and degree of canopy closure on the fix rate and the positional error, and collars were deployed on 16 free-ranging bears to examine the fix rate and the effects of fix interval on fix rate. In the stationary tests, the proportions of no fix and of 2D fix (vs. 3D fix) increased as canopy closure increased and antenna orientation was further from vertical; at an antenna angle ≥90° from the vertical and canopy closure of 76.2–79.1%, the fix rate was <50%. The positional error for 3D fixes (ranged from 6.84 to 16.43 m) was significantly lower than that for 2D fixes (ranged from 30.74 to 43.45 m), and the positional error for both was affected by canopy closure and GPS antenna angle. An expected multipath effect on positional errors by rain was not statistically significant. Mean fix rates on collared bears ranged from 23.6% to 56.4% and were significantly lower than those in the stationary test. The fix rates at 5-min intervals were significantly higher than those at 4-hr intervals. Although our tests revealed some limitations and biases, GPS collar appears suitable for studying the movement and behavior of the bears.

Over-Winter Weight Dynamics in Supplementally Fed Free-Ranging Sika Deer (Cervus nippon)

Continuous body weight dynamics in supplementally fed free-ranging sika deer (Cervus nippon) during the three consecutive overwinters (from January to April), 1992–1994 were surveyed. Almost all individuals lost weight continuously throughout each winter (adult deer 5–13%; young deer 3–19%) and several deer lost weight even in April. Weight gain after loss began in the mid-April when ambient temperature increased and when plant growth began. Weight dynamics varied according to sex, age and reproductive status. Adult deer showed significant large weight loss than the young. Young deer lost weight (calves 18±11 g/day, yearling and two-year-olds 27±29 g/day) more slowly than the adults (65±23 g/day). Following this study of over-winter body weight dynamics, it seems that early springs are the most critical periods for the survival of free-ranging sika deer because of their poor nutritional condition.

Relationships between Swida controversa fruit phenology and fruit removal behaviors of frugivorous birds

Abstract The behavior of frugivorous birds during the removal of fruit from Swida controversa was investigated to compare the relationships between measures of fruit maturation and quantitative fruit removal behavior of birds. Bird exclusion devices were used on some branches to allow comparison of the traits of removed and un-removed fruits. Nine bird species visited S. controversa, but only four removed fruit, and each bird species removed a different number of fruits per visit. Only 11.5% of a branchs fruits were removed by birds. Birds removed only larger, blacker, more mature fruits, suggesting birds were effective seed dispersers.