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Population management of herbivores is widely applied to decrease damage to forests in the northern hemisphere. Culling more antlerless deer, including females and fawns, is an effective means of reducing the population and helps to improve management efficiency. To increase the efficiency of antlerless-biased culling, we assessed the spatiotemporal distribution of the antlerless ratio in culled sika deer (Cervus nippon) in relation to population density. We hypothesized that the antlerless ratio is higher at the center of the distribution than at the margins of the deer’s range, because dispersal processes differ according to sex and age: Young male deer first disperse into an unoccupied area, and then males may become established in the new area for approximately 10–15 years before the number of females increases. A statistical model revealed spatiotemporal changes in the antlerless ratio of culled sika deer. The change in the ratio basically fit the density distribution of the deer, which was estimated independently on the basis of fecal pellet count surveys. The antlerless ratio estimated from the model increased asymptotically as deer density rose. The results support our hypothesis and suggest that antlerless sika deer will be more easily culled at the center rather than at the margins of the distribution range. These findings should help to increase the efficiency of managing the deer via antlerless-biased culling.

Regional management of large herbivore populations is known to be effective in reducing local economic damages and conserving local endemic plants. However, herbivores often move across management areas, and the effect of population management on a large spatial scale is poorly understood, even though it is necessary to use a large-scale approach across multiple management units to implement appropriate management. In this study, to better understand large-scale management and improve management efficiency, we evaluated effects of large-scale management of a sika deer (Cervus nippon) population on Kyushu Island (approximately 36,750 km2) in Japan. We estimated the population dynamics and spatial distributions of the deer and evaluated the effects of harvests, density dependence, and climatic conditions on the population dynamics both across Kyushu Island and in smaller prefectural management units. Fecal pellet count surveys conducted from 1995 to 2019 and results from a vector autoregressive spatio-temporal model showed relatively stable population dynamics and four high-density core areas. No increasing or decreasing trends were observed in the population dynamics, even though harvesting increased annually until it reached about 110,000 in 2014, indicating that harvesting was not related to the population dynamics. In addition, although no effects of density dependence were confirmed, maximum snow depth during winter decreased deer density at the management unit scale. Harvesting represents a major source of mortality in the Kyushu Island population because of the absence of predators. Although, approximately 110,000 sika deer were harvested annually after 2014, it is surprising that the effect of harvesting on population dynamics was not significant. A main cause of no reduction of the population was that the population used to determine the harvest number was underestimated. In addition, it was indicated that multi-management units need to manage the core areas because the high-density core areas were located across a few management units. This study highlights the difficulties involved with wide-area management of large herbivores and points out the importance of accurate stock assessment, reduction of the risk of management failure, and cooperation among management units. Our research is an important contribution to the study of the effects of large-scale harvesting in a large geographic area.

The Asian black bear inhabiting the Shimokita Peninsula, the northernmost part of Honshu, Japan, is categorized as one of the endangered local populations (LPs) in the list of threatened species under the Endangered Species Act. The Shimokita population has become geographically isolated and fragmented due to recent human activity. In this study, we conducted DNA sampling between 2005–2007 of two neighboring bear populations across two regions, Shimokita and Tsugaru, and analyzed the genetic characteristics from the mitochondrial control region (approximately 700 bp) and seven microsatellite loci. Based on the analysis of both microsatellite markers and the mitochondrial control region, we found that the genetic diversity of the Shimokita population was lower than that of the Tsugaru population. An assignment test showed that three of 112 individual bears migrated between subpopulations, suggesting the low level of gene flow between subpopulations. The extent of genetic differentiation between p...

It has been suggested that the physical condition of a mother may affect her pattern of investment in her sons or daughters. In addition, when competition over local resources becomes intense, severe aggression among the philopatric sex leads to a higher mortality of the sex and a biased birth sex ratio toward the opposite sex in the low rank. Parental sex-biased investment has been studied in many animal species to test these hypotheses, but the results have been highly inconsistent. We examined maternal sex-biased investment in relation to dominance rank using data on infant growth, infant mortality, birth sex ratio, and delay of subsequent reproduction by rearing current offspring from a provisioned, free-ranging Japanese macaque (Macaca fuscata) troop at Takasakiyama, Japan. The results showed that there was no sex difference in infant body mass among offspring of high- and low-ranking females. Use of the logistic regression model to analyze infant mortality with several independent variables failed to show a statistically significant sex bias. Birth sex ratio did not differ significantly between high- and low-ranking females. Among high-ranking females, there was no significant difference in delivery rate in the next year between those that reared a son and those that reared a daughter. For low-ranking females, however, the delivery rate after rearing daughters was markedly lower than that after rearing sons. Thus, there was no evidence of statistically significant maternal male-biased investment. For low-ranking females, we found a delay in subsequent reproduction for mothers after rearing daughters and no sex difference in offspring mortality. These results suggest that the females increased their offspring’s chances of survival, irrespective of sex, by postponing their subsequent delivery.

Geographical variation in climatic cues for masting of Fagus crenata Blume, which is the most dominant tree species in Japanese temperate forests, was investigated in the northern part of Japan, i.e., the Tohoku district of Honshu Island and the Oshima Peninsula of Hokkaido Island. The data obtained after an 18-year assessment (1989–2006) of 163 stands, covering an area of ca. 200 × 500 km2 area, were used in this study. In all stands, mast seeding occurred three times (1995, 2000 and 2005) during the study period and the coefficient of annual variation (CV) in seedfall density was 0.94. Based on cluster analysis, the stands were classified into each of the seven groups, in which the seedfall density was temporally synchronized among the stands and showed higher values of CV (1.04–1.79). These groups were distributed spatially exclusively at the scale of 80–200 km. By selecting the tree model based on AIC values, lower temperature in spring, higher temperature in summer and seedfall density in a year were proved to have a decisive influence on the seedfall density in the subsequent year. The effects of the first two climatic cues overwhelm that of the seedfall density. Lower temperature in spring served as a cue mostly for the population in the Oshima Peninsula, while higher temperature in summer served as a cue for the populations in the Tohoku district. If this suggests a genetic variation in relation to cues, climatic changes (e.g., global warming) will have different impacts on seed production of different F. crenata populations. However, it remains to be tested in future studies whether multiple climatic cues simply reflect regionally variable climatic conditions or not.

Fluctuation in the number of Asiatic black bears, Ursus thibetanus, culled in 1993–2004 was analyzed for 25 areas from 23 prefectures in Japan by cluster analysis. The areas were roughly divided into two groups, one consisting of areas west of Toyama, and the other consisting of areas east of Nagano, which was further divided into three clusters. Each cluster was composed of areas (prefectures) that were geographical neighbors except for four areas that were not merged into any clusters. It was likely that the number of culled bears in the residential area was affected by an inter-prefectural factor. These findings kept open the possibility of forecasting the increase of nuisance bears based on hardmast monitoring, although which tree species and how strongly bears depend on them are still unclear. Further monitoring on the number of nuisance bears and hardmast production level is needed.

Minimizing human-caused mortality by providing alternative solutions to human–bear conflicts is important for the conservation and management of Asiatic black bear (Ursus thibetanus) populations. We found a positive correlation (P < 0.05) between the number of nuisance bears killed and a beechnut (Fagus crenata) crop failure index in 5 of 7 zones in the Tohoku region of Japan. In areas where bears are highly dependent on beechnuts as food in autumn, we suggest that agencies could issue warnings about nuisance bears in years of crop failure using the current monitoring network of beechnut production. This system could be a valuable method not only to reduce human–bear conflicts but also to enhance public consciousness of bear conservation and management.

Elucidating the genetic relationships among members of a social group is indispensable in studying any social system of primates.Hylobates spp. are believed to be monogamous, although some long-term monitoring studies have provided conflicting evidence. We applied a parentage testing technique to a group ofHylobates muelleri in the wild. Forty-five microsatellite loci were screened in the 12 unrelated gibbons' DNA, and 16 of the 45 loci were found to be polymorphic. Hair and fecal samples from 15 gibbons in the field were collected non-invasively. In each sample, the 16 polymorphic loci were amplified by PCR using appropriate primer pairs and separated by electrophoresis. We estimated three pairs of parents-offspring, a pair each of both father-offspring, and mother-offspring genetic relationships. Further, in two of the five cases, we revealed the family a subadult lived with was not a natal one of the subadult. The non-invasive sampling methods and polymorphic primer pairs used in this study would greatly enhance the understanding of gibbon's society in the wild.

The size and spatial distribution of home ranges in two sympatric field mouse species,Apodemus speciosus andApodemus argenteus, were revealed by the capture-recapture method in a temperate deciduous forest from June 1987 to June 1990. InA. speciosus, the home ranges of males were significantly larger tha those of females, and overlapped with those of other males and females during the breeding season. InA. argenteus, the home range of each male overlapped only that of a single female throughout the year. These results suggested thatA. speciosus was promiscuous or polygynous andA. argenteus was monogamous.

Increasingly, attention is being focused on tropical forests. This interest has been motivated by three main concerns: 1) Tropical forests harbor the greatest biological diversity on Earth; 2) they are a major component of the global carbon cycle; and 3) they provide forest goods and services to all sectors, from the local to the global scale. These three concerns often cause conflicting problems in forest management, and forest scientists and administrators are seeking a harmonious solution. Despite recent advances in the understanding of tropical forest ecosystems, knowledge is still insignificant in relation to the three concerns mentioned above. To establish verifiable forest management methods that are ecologically sound, economically viable, socially responsible, and environmentally acceptable, both administrators and scientists including those in the fields of socio-economics, plant ecology, eco-physiology, soil science, animal ecology, entomology, mycology, pathology, silviculture, and forestry have collected accurate and detailed information about the changing forest ecosystems in the tropics.

According to a report compiled by the World Conservation Monitoring Centre (WCMC, 1996), the remaining closed-forest area (that is, the area having a tree-crown cover of over 30%) in Indonesia is about 117.9 million ha, and is being reduced at a rate of 1.2 million ha per year, due to forest fires and clearing for agriculture and plantations. However, the WCMC report does not mean that a vast forest has been gradually reduced from its edges inward. In other words, we must remember that deterioration of forests means not only gradual reductions in area but also division into smaller, isolated fragments (Harris 1980, 1984, Wilcove et al. 1986, Shafer 1990).