屋久島のニホンザル生息状況の過去20年間の変化

抄録

We studied the changes in the abundance of wild Japanese macaques (Macaca fuscata) in lowland Yakushima from 1991-1994 to 2013-2014. We quantified the abundance with the detection frequency by point observation. We used data for 271 points censused in July-August 1991-1994 and 58 points censused in July-September 2013-2014. Abundance of Japanese macaques significantly decreased in northern and eastern areas, but not in the western and southern areas. Comparing the estimated population in 1991-1994 and the number of hunted macaques for pest control in 2007-2013, hunting pressure seems to be high in the northern and eastern, low in the southern and none in the western areas. Conifer plantation is more widespread in eastern and northern areas, which may also explain the declining trend of the macaque population in these areas. The number of macaques hunted for pest control exceeded 1,000 each year from 2009 in Yakushima. Our results suggest that macaques are overhunted in Yakushima, so we recommend putting more emphasis on measures against crop-raiding other than pest control, in particular in eastern and northern areas.