Based on the articles in a recreational angling magazine, it is clear that the Sakhalin taimen (Hucho perryi) (Salmonidae) was once widely distributed across Hokkaido Island, northern Japan, but has declined rapidly since the 1980s. This decrease is probably the result of the loss of riparian forests and riverine habitats associated with extensive development of agricultural land during the 1960s and 70s.

抄録全体を表示

We studied the nest types used by Pteromys volans orii in two small, fragmented woods (2.1 ha and 3.1 ha) in Obihiro, Hokkaido from April 2005 to March 2006. Three nest types (cavity, nest box, drey) were used by eight flying squirrels. Each flying squirrel made use of two to eight nest-sites. The flying squirrels in our study area appear to have been restricted as to nest resources, since these woods are fragmented and small, they are surrounded by roads and fields. The preferred nests during snow-free and the snowy season were, respectively, cavity and nest box, and cavity and drey. We suggest that longer and more frequent use of nest boxes during the snow-free season might be related to rises in temperature and numbers of ectoparasites. The use of specific cavities during the snowy season appears to relate to their internal thermal characteristics. We also suggest that, to conserve flying squirrel populations which inhabit small, fragmented patches, more available nests of better quality are needed.

抄録全体を表示

A survey was conducted of the regional distribution of the Japanese giant flying squirrel, Petaurista leucogenys, in the six hilly areas of Southern-Tama district, Tokyo. The results of the survey were overlaid the land cover map derived from LANDSAT data. Fragmentation of wood land, type of vegetation cover, and area of habitats were determined quantitatively using GIS. It was confirmed that there is fragmentation of the habitats of the Japanese giant flying squirrel for example the woodlands in the Tama hilly area. We suggest that continuous woodland over areas equivalent to the average range of the Japanese giant flying squirrel is required to ensure sustainable population within the habitat, and that isolation and fragmentation of woodland has a significant influence on the sustainability of the habitat for this species. In the woodlands of the hilly areas of Southern-Tama district, where deciduous trees are dominant, it appears that the higher proportion of evergreen trees than the local average improves the value of the habitat for the Japanese giant flying squirrel.

抄録全体を表示

Ichthyofauna and feeding habits of salmonid fishes were investigated in a small stream on Shiretoko Peninsula, northern Japan. Dolly Varden (Salvelinus malma), white-spotted charr (S. leucomaenis), masu salmon (Oncorhynchus mason) and rainbow trout (O. mykiss) inhabited the stream. Rainbow trout, an alien species in Japan, dominated the lower reach of this stream, which is concrete-lined. Dolly Varden, a native species, dominated the upper reach, which has a mainly natural riverbed. White-spotted chary and Dolly Varden mainly consumed terrestrial and aquatic invertebrates, respectively. The smaller rainbow trout foraged for aquatic invertebrates, while larger ones consumed various animals including of gobies (benthic fish).

抄録全体を表示

Since the 1970's, the number of hunters in Shimane Prefecture has declined greatly. The administration worried about reduced hunting pressure on nuisance animals such as wild boar, adopted a new policy to make it easier for hunters from other Prefectures (nonresident hunters) to be active in Shimane. To estimate the effectiveness of this policy, we investigated the activities and attitudes of nonresident hunters. More than half engaged in wild boar hunting (62.3%), and a considerable proportion hunted with guns (72.5%). Gun hunters targeting wild boar were concentrated in a few counties and were members of domestic hunting groups. About half of the wild boar hunters complained that there were too many snares, which can entrap their hunting dogs. Another policy within Shimane Prefecture, aimed at increasing the number of hunters is to encourage farmers to apply for hunting licenses. Most farmers use traps rather than guns for hunting because the equipment is easier and cheaper to maintain (Ueda and Kanzaki 2006). As a result of this policy, the hunting environment for gun hunters has deteriorated. Not only domestic gun hunters but nonresident hunters have decreased. We suggest that the Shimane Prefectural government should consider the consistency of these two policies both of which were intended to increase the hunting pressure on nuisance animals.

抄録全体を表示

Luehdorfia puziloi (Lepidoptera: Papilionidae) is a monophagous univoltine butterfly; its adult flight period in Japan from April to May. Although the butterfly appears on the Japanese Red List (status: Near Threatened), detailed data about its ecology is insufficient to inform conservation decisions. Therefore, we estimate the survival rates in a population of L. puziloi on Mt. Aoba, Miyagi Prefecture using a modification of the Kiritani-Nakasuji-Manly method. The habitat is a deciduous broad-leaved forest dominated by Quercus serrta and its core is approximately 50 m long and 30 m wide. We surveyed the numbers of eggs and larvae in the habitat 11 times from April 10 to June 23,2005, and obtained the following estimates of daily survival rate: egg to the first instar larva, 0.98; first to second instar larva, 0.97; second to third instar larva, 0.96; third to fourth instar larva, 0.96; fourth to fifth instar larva, 0.90. We also obtained the following estimates of population size: 517 eggs; 440 first instar larvae; 362 second instar larvae; 243 third instar larvae; 225 fourth instar larvae; 111 fifth instar larvae. The estimated number of adults that emerged on April 15, 2006 were 14.3 based on a Bailey's triple catch method. Therefore if we assume that there were no migrant adults form other populations, the estimated survival rate from egg (517) to adult (14.3) was 2.8%.

抄録全体を表示

This paper analyzes the background of local people who accept the 'co-existence' with the presence of white storks (Ciconia boyciana) in Toyooka city, Hyogo Prefecture. The chi-square test was applied to the results of a question-naire, targeted at the local people, about their perceptions relating to the release of white storks. I selected four questions designed to evaluate whether people accepted the presence of white storks. The responses were examined in relation to respondents' attributes (for example, 'age', 'sex', 'concern for environmental issues') by means of the chi-square test. The results showed that 'age', 'attachment to area of residence (Toyooka city)', 'concern for environmental issues' , recognition of Mr. Matsushima', and 'past or current sightings of white storks' were all connected to acceptance of the presence of the species. This demonstrates that local people accept the storks by adding values to their presences: 'the symbol of the region', 'the symbol of a rich natural environment' and 'the constant demands to release white storks presented mainly by Mr. Matsushima'. It can be said that adding values creates "distance" between local people and the white storks and facilitates co-existence of the two.

抄録全体を表示

The distribution of feral raccoons was studied in the northwestern part of Kanagawa and the eastern part of Yamanashi prefectures. This study was conducted with the interview survey and by the automatic camera. It was clear that the distribution of raccoons in the northwest of Kanagawa had expanded in comparison to previous data. It was confirmed that the raccoons population had reached Yamanashi. In any future control strategy, the highest priority should be the removal of raccoons in northwestern Kanagawa and eastern Yamanashi. Range expansion of this species may be facilitated by the Sagami and the Doushi rivers. The presence of raccoons was also confirmed in the border between Kanagawa and Tokyo. Thus, collaboration with Tokyo and neighboring prefectures is necessary to prevent future range expansion of raccoons in these areas.

抄録全体を表示