Search

A series of censuses of wild Yakushima macaques (Macaca fuscata yakui) was carried out in a 127.26km2 area around the coast of Yakushima Island, Japan. The census area was estimated to have 131 troops in total. Monkeys seem to depend on natural broad-leaf forests. Troop density was highest in the western coastal area, where the greatest population of natural vegetation remained undisturbed. In total, 1, 852 monkeys were counted, giving an estimate of 2, 000-3, 850 monkeys inhabiting the census area.

In the previous research in 1993, three of the authors found that some troops of wild Japanese macaques were provisionized by tourists, around the road in the western forest of Yakushima Island, south of Kyushu, Japan. Again in 1995, we conducted a research with the same methods in the same area. Here we reported the results of 1995 and compared them with those of 1993.We surveyed the area along the road of 19.2km, passing through the forest. We set eight stations along the road as survey units, with a mean length of 2.4km. Each station was surveyed for two days. Each of us walked slowly in the station and searched troops of monkeys. When the observer found the monkeys on or near the road, he or she began observation session for maximum of 30 minutes. At the end of observation session, the observer began to search another troop.During the observation session, we recorded the activities of monkeys and conducted“orange tests”. In the “orange tests”, we showed an orange to a monkey and recorded its response. If the monkey accessed to the orange, it was determined as provisionized.Percentages of provisionized monkeys were significantly different among the stations. However, no significant difference was found between the results of 1993 and 1995. Numbers of traffic passing through the road per day was 138.5, which was larger by 40 than in 1993. Among the traffic in 1995, at least 60% was due to tourists.The numbers of provisionized monkeys did not increased distinctively during the two years. However, numbers of tourists visiting the area apparently increased and the percentages of provisionized monkeys increased in some of the stations. Therefore, we should continue to monitor the provisionized monkeys and to make efforts to stop tourists from feeding monkeys.

The purpose of the present survey was to investigate the awareness of the public on the problems arising from provisioning. The social problems of provisioned wild Japanese macaques happens throughout Japan including Yakushima Island in Kagoshima Prefecture. A questionnaire was given to residents in Yakushima and to tourists visiting. Responses were obtained from 438 people. The results may be summarized as follows: (a) The majority of people questioned were aware of some of the social problems in wild Japanese macaques caused by provisioning. (b) Many people gave wild monkeys food for reasons of amusement and in the belief that it improved their situation. This questionnaire revealed that the public understood some of the issues described above but their actions appeared to contradict this. Consequently there is a need to develop a better understanding on the influence of man particularly in regard to feeding.

The area of World Heritage in the northwest of Yakushima is the only part of the island where natural vegetation still extends to the coast. The influence of the Seibu Road (19.3km) on this forest was investigated using three indicators. The first was physical discontinuity of the forest (P), which was determined from the lengths of artificial slopes above and below the road. The second was scenery disturbance (S), which was determined from the presence or absence of trees beside the road. The third was vegetational disturbance (V), which was determined from the number of invader plant species found alongside the road.In section of the road where has been relatively little disturbance the tree tops meet to form a “Green Tunnel”. The occurrence of such “Green Tunnel” sections was recorded continuously along the road.Discontinuity of the forest (P) was significant positively correlated with both scenery disturbance (S) and vegetational disturbance (V), such that section of the road which have been most developed have the least roadside trees and the greatest number of invader plant species. “Green Tunnel” existed along only one fourth of the whole length of the road and along only one third of the road within the World Heritage forest. Almost all of “Green Tunnel” sections were found in the Hanyama and Kawahara areas, where all three indicators also showed the low disturbance.These results suggested that, in order to conserve the natural environment of the World Heritage forest, the construction of artificial slopes above and blow the road should be avoided as far as possible.

Wild Japanese macaques (Macaca fuscasta yakui) around the Seiburindo Road in the western area of Yakushima Island have been occasionally provisioned by tourists. We censused the provisioned monkeys along the Seiburindo Road (19.2km) in this area.“Orange tests” were conducted for 236 individuals in 86 observation sessions to discriminate provisioned monkeys. Adult male monkeys were more provisioned than adult females or immatures.The median time for which they stayed around the road was 26 minutes in 30 minutes observation sessions. They mainly spent time on resting and foraging around the road.The areas where provisioned monkeys were observed had significantly larger artificial slopes than those where non-provisioned monkeys were observed. In addition, the number of groups that we found along the road were positively correlated with the height of the slopes. The amount of time for which we observed monkeys along the road also showed significantly positive correlation with the lengths of the slopes.These results suggested that, in the area where the artificial slopes were larger, monkeys tended to stay there for longer time and passengers could find monkeys more easily because of high visibility. Therefore, monkeys ranging larger artificial slopes might be more likely to contact with passengers and tend to be provisioned.