A research on the altitudinal distribution of forest birds was conducted on the Yakushima Island, south-western Japan, in winter, 1983. Three types of the assemblages of dominant bird species were recognized in respective plant formations from the coastal area to the mountain top : Hypsipetes amaurotis, Zosterops japonica and Parus varius in an evergreen broad-leaved forest (40-900 m) and in a Cryptomeria forest with evergreen broad-leaved trees (900-1200 m), Z. japonica, P. ater, Troglodytes troglodytes and P. varius in a Cryptomeria forest with deciduous trees (1200-1555 m), and Z. japonica, Turdus naumani and Emberiza cioides in a mosaic of a scrub of Pseudosasa and Cryptomeria forest (1555 m-1886 m). Overall, of the thirty-two species recorded, twenty-two were residents and ten were winter visitors. Of the seven dominant residents, three species shifted downward, one shifted upward, and three did not shift from their breeding sites. Winter visitors were characterized by many seed or fruit eaters, or ground-foraging insectivores and no canopy-foraging insectivores, which is in contrast to summer visitors. Winter visitors mainly invaded the Cryptomeria forest with deciduous trees or shrub in a forest edge, the habitats being liable to a great seasonal change.
Leaf expansion and shoot elongation of Cornus controversa HEMSLEY were studied in Ishikawa Prefecture in 1988. The overwintered buds burst in early April. Each of them expanded 7〜14 leaves by late May and developed to the first shoots. About 45% of the overwintered buds produced the second shoots. The earliest elongation of the second shoots was observed on May 18. The first shoots tended to have more leaves and attained great elongation, and their earliest expanding leaves were larger when they repeatedly produced new shoots. There was a significant positive corelation between the lengths of the first and the second shoots. A weak positive corelation was observed between the lengths of the first shoots of the current year and of the final shoots of the following year. These facts suggest that the elongations of the second and the higher-order shoots would greatly depend on the photosynthates of leaves of the first shoots.
Effects of the alteration of the management, such as interruption of weeding and removing fallen leaves from the forest floor, on the species composition and soil conditions of the secondary forests of Quercus serrata were studied in the western part of Musashino terrace, central Honshu, Japan. The forests were identified as the typical subassociation of Quercetum acutissimoserratae, and subclassified into the variant of lxeris dentata and the variant of Quercus myrsinaefolia. The stands under management turned out to be the variant of lxeris dentata, and the stands abandoned turned out to be the variant of Quercus myrsinaefolia. These facts show that the alteration of the management to the secondary forests of Quercus serrata changed the species composition and differentiated the under unit. Differences in soil conditions between the stands under management and the stands abandoned were clear mainly in the topsoils. Hardness, porosity, total carbon, total nitrogen, EC and exchangeable base (Ca, Mg, K) showed major differences. It was discovered that pedological physico-chemical properties became richer with the interruption of management to the secondary forests of Quercus serrata. It was considered in connection with the factor of the quantity of the litter and the physical property of the topsoil, whether the differential species of the variant of Ixeris dentata and of the variant of Quercus myrsinaefolia appear or not.
Leaf age sturucture at different light conditions was studied for 14 evergreen broadleaved tree species from October 9 to December 27,1989,to clarify differences of leaf longevity among species and light conditions. The patterns of the leaf age compositions of the observed species for each light condition were compared with each other and divided into 4 groups. The species, whose pattern of leaf age composition changed with light condition, changed their position into the group with higher age leaf under more shaded conditions. The mean maximum longevities became longer under more shaded condition for most of the species. Camellia japonica, Cinnamomum insularimontanum, Cleyera japonica, Photinia glabra and Aucuba japonica, grown under a lower tree layer with a shaded environment, were assumed to have a longer leaf longevity than other species. Ilex pedunculosa, Ilex chinensis and Cinnamomum Camphora, found even in the early stage of succession with light environment, were assumed to have a shorter leaf longevity than other species. Quercus glauca, Quercun salicina and Quercus acuta, from among the species possible to dominate in a tree layer of the climax forest, were assumed to have a shorter leaf longevity than other species. The last group of species was assumed not to be adapted to a shaded environment.
In order to clarify the variation of the life-history of Japanese charr Salvelinus leucomaenis inhabiting an artificial lake constructed by damming, their growth, maturity, reproductive chracteristics and down-migration pattern in the lake-inlet stream system were studied. Two types of mature fish in both male and female, stream residents and migrants, which were distinguishable by body size, coloration and secondary sexual characters were recognized. From analysis of their otolith radius length, migrants appeared to grow more rapidly than residents after 0+ of age. Females in both types matured from 2+ of age, but stream resident males were more precocious (from 1+) than migrants (from 2+). Juvenile fish which were mainly 0+ and fairly 1+, migrated down from inlet stream to the lake. Down-migration occurred nocturnally from May to october with a peak in May. The body length of migratory fish of 0+ was significantly shorter than that of resident fish in May and August, but no differences in the body length were observed in other months. Possible mechanisms as causes of different life-history patterns were discussed.
Polygonum cuspidatum Sieb. et Zucc. produced larger and heavier achenes with increasing altitudes of its habitats from basal zone to alpine zone, and the form of its achene's wings was also different. After seed germination at the experimental field in montane zone, the growth of the seedlings derived from high altitudes was more rapid in the early stage of their growth than that from low altitudes. But, three months later, germination seedlings derived from alpine zone showed a dwarf type on their aboveground parts. Some of the seedlings grown in this area came into flower within the year, and developed male flowers only on the plants derived from low altitudes while both male and female or female flowers only appeared on those from high altitudes. Such differences in some of the morphological characteristics between the achenes and the seedlings derived from low and high altitudes seem to be caused by the different levels of altitudinal climatic stress from their original habitats, and seem to be genetic. It is suggested that P. cuspidatum has developed an alpine ecotype in high altitudes where climatic conditions are severer.