Impact of Human Activities on Survival of the Japanese Black Bear

The range of the Japanese subspecies of the Himalayan black bear (Selenarctos thibetanus japonicus) has declined in western Honshu. In Kyushu and Shikoku, local populations are approaching extinction. Meanwhile, the annual harvest of bears has increased from less than 1,000 to over 2,000 between 1950 and 1972, largely resulting from the increasing number of control kills. The distribution dynamics and the ecological consequences of the impact of human activities on 4 subpopulations were studied. Reductions in bear range and outbreaks of tree damage by bears were found closely associated with the rapid disappearance of natural forest. Present control practices and the various types of habitat destruction made these subpopulations increasingly vulnerable, and in 2 cases, partial or complete elimination of a subpopulation was confirmed. Japanese forms of the Himalayan black bear are found on the islands of Kyushu, Shikoku, and Honshu. A form of the Asiatic brown bear (Ursus arctos yesoensis) occurs on Hokkaido. The original habitat of the black bear in central Japan is believed to have extended from subalpine coniferous forests at elevations of 1,500-2,300 m to warmtemperate evergreen broad-leaved forests that ranged from the coast to low-altitude slopes up to 500 m elevation. Forests in the warm-temperate zone have long been exploited and are now largely destroyed. The range of the Himalayan black bear was progressively reduced and became confined to mountainous areas in the cool-temperate (500-1,500 m) and subalpine zones at medium to high elevations. This situation remained fairly stable until the early 1950s. Large-scale exploitation and destruction of natural forests in the cool-temperate and subalpine zones began in the late 1950s. Bear damage to conifer regeneration has apparently increased since 1970 (Watanabe 1974). As a counter measure, bears were classified as a verminous species and trapping and killing have been encouraged by the government. The status of this species, the largest land carnivore in Japan, must be kept under rigorous scrutiny in view of the critical circumstances stated above. Records of the total number of bears killed annually in each prefecture and of timber and agricultural damage by bears are available from the Environmental Agency and the Forestry Agency, respectively. However, the records are too meager for critical evaluation of the changing population status and of the consequences of recent human actions. Studies of the combined effect of habitat changes and hunting pressures are exceedingly scarce, and thus the present status of black bears is not well understood. Takahashi (1974), Watanabe and Komiyama (1976), and others have expressed grave concern over the risk involved in present land-use and forestry practices, which threaten the survival of black bears. The aim of this paper is to present interim results of studies of 2 subpopulations in central Japan and a literature review of the status of 2 subpopulations in western Japan, which may be informative and may help us to evaluate the impact of present policies on the bear population. Sincere appreciation is due K. Imanishi, former president of Gifu University, who encouraged the initiation of, and made arrangements for, the start of the research project. The field studies (1973-75) in Gifu were financed by the Department of Environment, Gifu prefecture. Throughout all phases of the work, we received active cooperation from the members of the Crescent Bear Research Group: T. Itoh and K. Maeda of Gifu College of Dentistry, E. Nozaki of Tokyo University of Agriculture and Technology, T. Aoi of Hokkaido University, and others. Field assistance by the students of the Brown Bear Research Group was most helpful. Without their participation, the field studies would not have been possible. M. Asahi of Hyogo Medical College and K. Hayashi of the Japan Monkey Center supplied valuable information and advice and, with K. Eguchi of Kyushu University, kindly allowed citations from their unpublished data. Last, but not least, heartfelt thanks are due the residents of our study areas, who generoulsy shared with us their knowledge of bears and rendered assistance in many ways. This paper is in fact the joint product of all those who contributed to the study. TRENDS IN HUNTING STATISTICS The following is an analysis of hunting statistics from 1950 to 1972 taken from Asahi (1977). During the past 22 years, the number of black bears killed has increased from less than 1,000 to over 2,000 animals per year. a linear regression on harvest (H) and year (X), H = 801.78+ 62.18X, was obtained and found to be highly significant (P<0.01)(Fig. 1). The rate of in72 BEARS THEIR BIOLOGY AND MANAGEMENT SELENARCTOS H=801.78+62.18x (P'* 0.1)