Masaaki Koganezawa

The effects of food sources on Japanese monkey home range size and location, and population dynamics

The effects of supplemental feeding by tourists on wild Japanese monkeys home range size and location, and troop size and composition were studied for two monkey troops, Troop A and Troop B, living along the Irohazaka loop road, Nikko National Park, central Japan. Changes were documented based on data gathered from 1982 to 1996 by the use of radio telemetry. Troop As home range size shrank and changed from separate winter and summer ranges to a single, year-round home range, with its core located in a high elevation area where supplemental feeding by tourists was heavy. Troop Bs home range also shrank and shifted to a lower elevation where supplemental feeding by tourists was heavy. Troop As population size increased between the winters of 1983–1984 and 1990–1991 in conjunction with an increase in human encounter rates, and then decreased. Troop Bs size increased until the winter of 1993–1994, and then decreased. The instability of troop size between 1993 and 1996 may be explained by documented factors such as a decrease in the adult sex ratio, an increase in the infant-female ratio, and an increase in juvenile mortality and/or emigration, all of which may have been influenced by supplemental feeding by tourists.

Seed removal and survival in Asiatic black bear Ursus thibetanus faeces: effect of rodents as secondary seed dispersers

We investigated the fate of seeds of five tree species hill cherry Prunus jamasakura, Korean hill cherry P. verecunda, Japanese bird cherry P. grayana, giant dogwood Swida controversa and crimson glory vine Vitis coignetiae in the faeces of the Asiatic black bear Ursus thibetanus in a temperate forest in central Japan. Clarifying the fate of seeds dispersed by endozoochorous seed dispersers will enhance assessments of their roles as primary seed dispersers. We established several experimental treatments in the field. Each faeces sample was covered by cages with different mesh sizes which limited accessibility by animals (NM: no mesh, SM: 1 mm mesh and MM: 10 mm mesh). We examined whether seed removal varied among tree species and between mesh-size treatments from 2004 to 2007 (N = 625 samples). We set up an automatic camera trap 1.5 m above the ground at all NM treatments. In the NM treatments, the number of seeds of all tree species decreased immediately after the faeces were set. In June of the following year, < 1% of the seeds from any species remained in the vicinity of the faeces. However, we found 3.0-13.2% intact seeds of all species in the soil below the faeces, as well as within a 10-m radius around the faeces. In the NM treatments, most seed removals were observed within four days after the faeces were set. For all tree species in the MM treatment, most of the seeds were present on the surface of the soil, and 1-2% of the seeds germinated at the location where faeces were set. In the SM treatment, none of the seeds from any of the tree species disappeared and germinated. We took a total of 415 photographs at the NM sites, 97.8% of which were of rodents either holding or eating seeds. Many of the seeds contained in the bear faeces were removed and eaten by rodents. However, 2.1-5.1% of the seeds survived and germinated, which implies that rodents may also act as secondary seed dispersers.

Changes in the structure of the Japanese hunter population from 1965 to 2005.

Japanese hunter numbers have been declining from a peak of 532,265 in 1970 to 166,386 in 2005. We analyzed demographic changes in hunter numbers from 1965 to 2005 using data from all 47 Prefectures. Most hunters were licensed for guns in 1965, but hunter numbers have declined in every Prefecture after 1975. The number of hunters who were licensed to trap increased in most Prefectures after 1985. A Hunter Recruitment Index (HRI) of younger age classes was positive in most Prefectures between 1965 and 1975. HRI of all age classes was negative in most Prefectures during the1980s, but those of older age classes mostly turned positive drastically after 1995. Trends in the number of gun hunters and recruitment of younger hunters affected hunter population dynamics until the 1980s. The increase in the number of those who desire to catch nuisance animals using a trap would have affected it since 1990.

Age distribution, sex ratio and mortality of the red foxVulpes vulpes in Tochigi, central Japan: an estimation using a museum collection

One hundred and thirty carcasses of the red fox were collected in Tochigi Prefecture, by the Tochigi Prefectural Museum, from 1981 to 1991. The young/adult ratio of the sample was 1.60, which suggests that the hunting pressure has been relatively low in this area. Six percent of the animals were 5 years or older which compares to those taken in Hokkaido, but is higher than those in Europe and North America. The sex ratio for all specimens had a tendency towards male bias (0.587), but this bias was higher for the adult (0.605) than for the young (0.576). Among young (0 year-old) foxes, more individuals were killed on roads than by trapping or shooting (P<0.02, chisquare test). This mortality pattern was caused by high mortality of young males (P<0.02). The proportions of adults killed by the three mortality factors were similar, though only one of the 14 foxes older than 4 years old was shot, probably due to age-linked activity patterns. Most road-kills of young foxes occurred in May when juveniles began exploiting and in November when sub-adults began dispersal. The ratios of road-kills for the whole sample and for adults alone were 42% and 34%, respectively. These high rates of road-kills suggest that the mortality pattern in Tochigi has been affected by factors characteristic of urban environments.

Factors influencing winter home ranges and activity patterns of raccoon dogs Nyctereutes procyonoides in a high-altitude area of Japan

Between October 2006 and June 2007, we radio-tracked six adult raccoon dogs Nyctereutes procyonoides (Gray, 1834) in a high-altitude area of Japan to determine which factors influenced home ranges, daily movements, and activity patterns of Japanese raccoon dogs, with an emphasis on the winter season. The home-range sizes for the six individuals were smaller in winter than in autumn. In winter, the daily movement distances significantly decreased in response to decreasing temperature and increasing snow depth, suggesting these environmental factors contributed to a decrease in the home-range sizes during this period. Moreover, during daytime, raccoon dogs were more active in winter than in the snow-free periods (autumn and spring), and the proportion of the daytime movement distances to the total daily movement distances significantly increased as the mean daily air temperatures decreased. Therefore, it appears that the raccoon dogs in our study area passed the winter by minimizing their energy expenditure by restricting their movements when temperatures were at their lowest and snow depth was highest, and by moving more during the daytime when temperatures were higher.

Integrating Analyses of Population Genetics and Space-Time Information for Wildlife Management: An Empirical Study on Japanese Wild Boar Populations

Abstract. This study is a “model study” of how to apply the findings of molecular ecological studies to wildlife management, aimed at showing the importance of analyses integrating population genetics, space-time information and bioinformatics methods. We chose the Japanese wild boar (Sus scrofa leucomystax) in Tochigi Prefecture, Japan, because its captured area has been spreading in recent years. We used 72 adult individuals gathered by hunters in 2010. Three putative sub-populations were estimated using microsatellite DNA. Our study indicated that the individuals newly found in the northern area originated from other prefectures, not from different areas within the same prefecture, and no inobuta (crossbreeding with pigs) in the maternal line were found. Comparing the number of mutations obtained by a coalescent simulation with that obtained by mitochondrial DNA, suggested that an assumed native population in the eastern area of Tochigi Prefecture was actually not native. Habitat preferences of the putative sub-populations, estimated by a generalized linear model, were different from each other, which also suggested that the boar could adjust its habitat based on the characteristics of the local environment. Risk maps, estimated using MaxEnt, based on past questionnaire surveys and those based on microsatellite DNA were different from each other.

Stable Carbon and Nitrogen Isotopic Composition of a Whisker and Fur from a Stuffed 19th Century Specimen of the Extinct Japanese River Otter Collected from Inland Honshu, Japan

1 Graduate School of Symbiotic Systems Science and Technology, Fukushima University, 1 Kanayagawa, Fukushima, Fukushima 960-1296, Japan 2 Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima, Fukushima 960-1296, Japan 3 Center for Weed and Wildlife Management, Utsunomiya University, 350 Mine-machi, Utsunomiya, Tochigi 321-8505, Japan 4 Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima, Fukushima 960-1296, Japan

Indirect Effects of Sika Deer on Japanese Badgers

Abstract. Recently, the range of the deer has expanded worldwide, with dramatic increases in abundance; yet relatively little is known about how these increases influence other mammals at high trophic levels. A recent study showed that high deer density exerts cascading effects on raccoon dogs, omnivorous carnivores, because of any increase in their prey abundance in Oku-Nikko, Japan. Here, we examined the diet of Japanese badgers, another omnivorous carnivore, outside a deer-proof fence and compared carnivore abundance inside and outside the fence in Oku-Nikko, to assess whether high deer density outside the fence influences the carnivore. Earthworms and insects, the population of which increased by high deer density, were frequently found in badger fecal samples outside the fence. Outside the fence, the deer density was 13.5/km2 and the badger relative density was 0.16, whereas inside the fence, the deer density was only 2.3/km2 and the badger relative density was 0.01. A statistical test showed that this inverse relationship was significant. We propose that the grazing pressure associated with high deer density impacts habitat conditions, increasing earthworm and insect abundance, which then increases omnivorous carnivore foraging opportunities and population densities.

Genetic Variation in Six Loci of Serum Proteins and Red Blood Cell Enzymes in Japanese Sika Deer (Cervus Nippon) in Nikko National Park

日光国立公園に棲息するニホンジカの血清タンパク質および赤血球酵素6つの表現型を検出し,各対立遺伝子の出現頻度を求め,その集団における多型の有無を調査すること,さらに推定された対立遺伝子の頻度を用いて3つの越冬集団(表日光,奥日光,足尾)間における類縁関係の程度を明かにした.1996年から1999年までの各年の1月から3月に,日光国立公園で捕殺されたシカ個体より採取された血液試料を用いた.酸性フォスファターゼ(Acid phosphatase: ACP)および6-フォスホグルコネートデハイドロゲナーゼ(6-Phosphogluconate dehydrogenase: PGD)はデンプンゲル電気泳動法,グループスペシフィックコンポーネント(Group specific component: GC)およびヘモグロビン(Hemoglobin: HB)は等電点電気泳動法,ポストトランスフェリン(Post-transferrin: PTF)およびトランスフェリン(Transferrin: TF)は水平式ポリアクリルアミドゲル電気泳動法によりそれぞれ分析した.その結果,GC, HBおよびPTFにおいて多型が観察され,それぞれ3,2,3の対立遺伝子が検出された.さらに対立遺伝子頻度を求めたところ,これらの各対立遺伝子頻度の出現率において,3つの集団間に差異が認められた.また,平均ヘテロ接合度は,奥日光,表日光,足尾の順に高く,標準遺伝距離は,足尾～表日光で低く,奥日光～足尾間で高い結果となった.