Pleioblastus chino, one of the dwarf bamboos, is an important forage plant for the Sika deer on Kinkazan Island, northeastern Japan. Sika deer prefers this plant and the leaves mostly exhausted in winter. As the result of the long-term grazing, P. chino was reduced in its size and the total standing crop in the grazed plot was by far smaller the in the ungrazed plot. However, the following results showed that P. chino was considerably tolerant of grazing if the grazing was not excessively heavy : (1) the culm density was remarkably high in the grazed plot, (2) the proportion of leaf weight was greater in the grazed plot than in the ungrazed, (3) the P. chino community has been maintained as a bioclimax for these some decades. Under heavy grazing conditions, however, the P. chino community was retrogressively replaced by a Zoysia japonica community.
The activity studies of Japanese red foxes were conducted in the central Kyushu by means of biotelemetry. The foxes were mainly nocturnal. Nocturnal activity commenced in dusk and lasted with several intermittences till two hours after sunrise. The time of commencement and termination of the activity varied seasonally with the photoperiod. In summer, the level of nighttime activity was higher than in other seasons, but nocturnal habits were durable throughout the year. Several influencing factors were discussed. Particularly, it seemed that the outdoor human activity largely influenced the activity patterns of the foxes in this area. On the other hand, the changes of prey availability were apparrently not closely related to the activity. Female foxes which were nursing pups were active in the daytime as well as in the nighttime, but the total distance travelled in a day was short.
A simulation model of the seasonal variation of cycling of soil organic carbon was proposed, based on the data observed in a beech/fir forest on Mt. Odaigahara in central Japan. Essential phenomena of cycling of soil organic matter dependent on soil surface temperature were selected and formulated into a mathematical model. The results of the simulation proved to fit closely the data obtained in the beech/fir forest. This simulation model, therefore, was applied to an evergreen oak forest and a tropical rain forest. This model may be applicable to any type of moist type forest.
The present paper deals with patterns in spatial distributions of pelagic fish (Engraulis japonica, Trachurus japonicus, Scomber japonicus, Etrumeus micropus and Sardinops melanosticta) in coastal waters. It is based on the daily catch data obtained by eleven small purse seiners. It was found that commercial fishery could act as an efficient sampling method to study movements of fish group at a level of elementary population. Each species of the pelagic fish always constituted a separate and stable group, elementary population with a size of between 6 km and 11 km in an average diameter. Careful examinations of daily maps showing the distribution of each fish species suggested the presence of interrelationships between groups of pelagic fish.
Floristic and vegetational or between-habitat diversity of epilithic bryophytes were studied for 31 boulders that are scattered on a forest-floor in Unzen National Park, Japan. Surface area of boulders and environmental diversity represented as light-intensity variety (brightness-darkness index) and as a combined index of area and light-intensity variety are good predictors of the number of species and of life-forms of epilithic bryophytes. A new index of between-habitat diversity was proposed and named index of vegetational diversity (IVD). It can be applied to the regional vegetation that is classifiable into community-types, even in the case that the community interrelations are phytosociologically multi-dimensional and that some of the classified communities have few or no species in common with the others. The surface area and environmental diversity are also good predictors of the vegetational diversity of the epilithic bryophyte communities studied. Floristic and vegetational diversity are significantly mutually correlated.
A model was proposed to simulated the relationships among CO_2 evolution rate (R), apparent density (ρ) and moisture content (H) in wood litter decaying on the forest floor under natural conditions. The effects of water and air content on R at a fixed temperature were first formulated. Further introducing the effect of temperature into the formulation, R at any season of the year could be predicted with moderate accuracy for a few forest types Japan and tropical Asia. The model showed that R reached a maximum value at an intermediate water (or air) content, which in turn varied depending on the apparent density or the stage of decomposition of wood litter. Adopting the hyperbolic ρ-H relation, which is usually observed in natural wood litter, as the boundary condition for the model, a linear relationship between R and ρ was derived, giving evidence to support of the formulation proposed by YONEDA(1975b).
Courtship behaviour of males of three forms of Pardosa laura complex was studied. Courtship behaviour was specific to each form. Males of each form exhibited courtship behaviour towards females of other forms, but females refused courtship of males of the other forms, and mated only with males of the same form. This means that males can't distinguish the females of their own form among the different forms of the females, but females can distinguish males of the same form among P.laura complex. On the basis of this observation, it is considered that each form of P.laura is a distinct species from one another.
Oribatid mite communities of moss and lichen were investigated at 12 different altitudes on the northern slope of Mt.Fujisan. Samples were taken at every about 100 m height from 900 m to 2,330 m above the sea level. Structures of the communities were compared with one another by the WHTETAKER'S Percentage similarity. In the subalpine coniferous forest (Abies-Tsuga forest), the oribatid mite communities were very similar to each other. A total of 80 species collected was classified into several groups according to their range of appearance. Several species groups of the oribatids were found to be closely connected with altitudes and plant communities. Oribatid community of Larix leptolepis shrub (2,330 m alt.) was quite peculiar in having Ametroproctus reticulatus as the most dominant species, while in 8 among 12 stations the most dominant species was Tectocepheus velatus.
The distribution of a plant species should be elucidated by studying the relation between enviromental conditions and the characteristics at various phases of the life-cycle of the species. This study focuses on the seed and seedling stage of Quercus variabilis BLUME. Some characteristics of Q.variabilis at the stages of seed-fall, germination, elongation and lignification of root, and growth of shoot, were given through field surveys and growth experiments controliing temperature and light. Using these results, probable growth pattern from the stage of seed-fall to that of seedling were given at various model sites, and a model pattern of the distribution of Q.variabilis presented on a temperature gradient. This model explains well the distribution of Q.variabilis in Japan and its reproduction of the succeeding generation of the population in some of the secondary forests.