ニホンザル生息数推定法の検討

ニホンザルの保護管理をめざして

抄録

A method for the population estimation of Japanese macaques, Macaca fuscata, was studied for conservation. (1) A significant correlation was found between the increase of the distribution range of Japanese macaques and the decrease of the broadleaf forest by analysis of “Population Census and the Second Basic Survey on the Natural Environment(PCSBSNE)”and “the Statistics of Forestry”. The natural broadleaf forest range was deduced as a major limiting factor of the macaque population. (2) The fact that the group size and the size of the undisturbed broadleaf forests (deciduous or evergreen) within its home range are correlated each other was applied as the preliminary formula to estimate the total population of Japanese macaques. That is, the population of Japanese macaques in each forest was calculated from the area of the deciduous and evergreen forests separately where distribution of monkey troops is recorded. (3) The preliminary formula was modified by the comparison with the actual observation in several sample areas. (4) Finally, areas in each vegetation type throughout Japan were measured from PCSBSNE and the total number of Japanese macaques in their natural habitat was estimated to be 114, 431.
For drawing up a more precise formula, other factors influencing the population size is needed to find through exact observations at more sample areas. For the wildlife management of Japanese macaques, periodical assessment of the Japanese macaque population and the habitat quality are required.