N., 1988: Effects of resource limitation on the physical and reproductive condition of sika deer on Nakanoshima Island, Hokkaido. Acta theriol., 33, 13 :187-208 2 ) were studied during a 5-year-period. The population density increased from 31.5 deer/km 2 in 1980 to 57.5 deer/km 2 in the autumn of 1983, and declined the following winter to 26.3 deer/km 2 due to both natural mortality (22%) and removal (32%). As the population increased, availability of summer and winter forages rapidly decreased. Deer had eliminated dwarf bamboo by 1983, which was the most important forage in winter, and were forced to consume more bark and unpalatable plant species. In the winter of 1983-84, in conjunction with a longer snow cover than usual, a mass mortality (22%) from starvation was recorded. Although the body weights and skeletal size of island deer initially were almost the same as those of mainland deer, the 1984 animals of both sexes were smaller in body weight and chest girth than the 1982 animals. Sexual dimorphism in body weight and measurements (chest girth and hind foot length) became apparent only after 1.5-years-old in 1982, and after 2.5-years-old in 1984. Skeletal growth (jaw length and skull length) gradually declined in immature age classes with a higher population density. Antler growth, associated with the decrease in body weight, also decreased. The ratio of fawn to one-year-old or older females in autumn declined drastically from 65% in 1980 to 7% in 1984. Resource limitation caused by high population density, and fluctuating climatic conditions are the main factors that determined both the size of the individual deer and the population.

Because the effects of land-use change on biodiversity have primarily been examined at or below the regional scale, it remains unclear whether such effects scale up to the macroecological scale (i.e. nationwide or continental scale). In Japan, forests have become more mature since the cessation of most forestry efforts in the 1970s. At a nationwide scale, this forest maturation may lead to reductions in the abundance of species that depend on early successional forests (early successional species) and increases in the abundance of species that depend on mature forests (mature forest species). Japan has met its high demand for wood through imports from South-east Asia, resulting in deforestation there. Therefore, the abundance of mature forest species that migrate long distances to overwinter in South-east Asia may decrease. We examined changes in the range sizes of birds in Japan over the past 20 years using the living planet index (LPI). The LPI indicated that the range sizes of early successional species decreased. For mature forest species, the range sizes of long-distance migrants decreased, whereas those of short-distance migrants and residents increased. Our predictions were generally supported. Our results indicate that the effects of land-use change extend to the macroecological scale and that such changes in one country can affect the biodiversity dynamics in other countries. Forest maturation in Japan and concomitant deforestation in South-east Asia have been caused by internationally coupled socioeconomic processes. Therefore, biodiversity conservation at the macroecological scale must consider the role of land use, and such efforts will require both international and socioeconomic perspectives.

These results strongly suggest a possible contribution of the VEGF-VEGF receptor system to the growth of intracranial AVMs.

Functionality of cheek teeth is essential for ruminants to masticate plant materials thoroughly and promote microbial degradation in their rumens. Thus, an excessive rate of tooth wear is expected to lead to premature loss of tooth functionality, and hence to reduced longevity. So far, however, the relationships between food habits, molar wear and longevity have not been investigated. We first compared molar wear rates among nine sika deer Cervus nippon populations with different food habits. We then investigated correlations between molar wear rate and two ecological factors, percentage of graminoids in diet and annual precipitation, relating to intrinsic and extrinsic abrasiveness of the ingested food, respectively. Secondly, we estimated 'retained molar durability' (molar height at a given age divided by wear rate) at successive ages for each population, and tested for correlation between molar durability and life expectancy among populations. The M 1 and M 3 wear rates differed among the populations and showed a positive correlation with graminoid consumption and a negative correlation with precipitation, suggesting that both ecological factors influence molar wear rates in the Japanese sika deer. M 3 durability had a stronger correlation with life expectancy than M 1 durability, especially at the older age stages. This implies that the influence of M 3 durability on life expectancy becomes stronger at the time when the M 1 is severely worn and loses its functionality, and is therefore more important for life span elongation than the M 1 . These results are concordant with the fact that the M 3 is the most hypsodont molar in many ungulates. In the Japanese sika deer, microevolutionary acquisition of hypsodonty appears to be the case in a northern population (the Kinkazan Island), whose molar wear rates are extremely rapid due to their food habits.

No abstract