The rate of production, accumulation, and disappearance of litter was studied in a tropical deciduous Zizyphus jujuba shrub community located on a Vindhyan hill in India. A gradual increase in the production of leaf and non-leaf litter was observed during three consecutive years. The contribution made by leaf litter to the total litter production ranged between 68.56 and 78.45 per cent. In the leaf component, the production of twig litter was always higher than that of the fruit litter. An experimental study of the leaf litter decomposition using the nylon bag technique revealed that within a year, 96.42 per cent of the initially placed litter decayed, of which the rainy, winter, and summer seasons shared about 68.04,18.50 and 9.88 per cents, respectively. Significant (P<0.001) positive correlations among the weight-loss, CO_2 evolution, and moisture content of the litter and soil were recorded. More accumulations of undecomposed residual litter were found during the summer months when the microbial activities were reduced due to the high temperatures and low moisture content. The turnover rate of the leaf litter was found to be higher than that of the non-leaf litter. It was observed that the litter bag provided an estimate of decay which was biased towards low values.
The food habits of chipmunks were studied by feeding observations in an oak forest for six years. In 1711 sightings of feeding, 41 plants and 16 animals (mostly insects) were identified. Various portions of the plants (seeds, fruits, buds, leaves, flowers and sap) were utilized in different seasons. Acorns were consumed in as many as 21 percent of the total number of sightings. Crown foraging for cherry seeds and elm samaras was common in early summer, and in late summer the chipmunks frequented crop fields for wheat. The number of available food items decreased markedly in autumn, although many acorns were consumed and hoarded during this period. Scattered and nest hoards were actively made in autumn, but the former was not consumed during winter. The overwintered acorns in the scattered hoards and fresh vegetables were heavily utilized in spring. Significantly, the fluctuation of acorn production affected the reproduction of chipmunks in the following year. Thus, the active, scattered hoarding activities in autumn appear to have an important function in the spring life of chipmunks.
Drosophila sordidula and D. lacertosa are long-day species. In D. sordidula the critical daylength falls between 14 and 16 hr at 18℃, while in D. lacertosa it falls between 12 and 14 hr at 18℃ and 14 and 16 hr at 15℃. D. sordidula responds to a constant high temperature by averting diapause, and to a temperature decrease and a constant low temperature by entering diapause even in a long daylength. These responses were less clear in D. lacertosa. The outdoor cultures of D. lacertosa showed a variation in the timing of the diapause induction in different habitats, such as the forest floor and cliff-shelter, but those of D. sordidula showed a more synchronized entrance into diapause.
Chikuranuma pond has been derived from a dammed lake made by lave of Chikura volcanic mountain erupted in Pleistocene. According to a phytosociological study by the Braun-Blanquet approach, the following plant communities were recognized : one kind of floating leaf community, three pond shore communities, three sedge swamp communities, and two swamp forest communities. From the result of pollen analysis, the vegetational change of Chikuranuma for approximately 9,500 years was traced.
This paper deals with pollen analysis of a 520 cm core (34°29'N lat., 131°35'E long.; alt. 390m) collected from the Ubuka sedimentary basin at the western edge of the Chugoku Mountains. The pollen history probably spans back to about 25,000 years B.P., i.e. from the last full-glacial maximum to the present, and would serve as a standard in the region. It is divided into five pollen zones in which seven vegetational stages are recognized. These are : I. Zone FG (ca. 25,000-15,000 years B.P.) 1. Pinus-Abies-Picea-Tsuga Stage (520-290 cm) II. Zone L (ca. 15,000-10,000 years B.P.) 2. Pinus-Abies-Picea-Tsuga-Betula Stage (290-170 cm) III. Zone R I (ca. 10,000-9,000 years B.P.) 3. Betula-Quercus-Pinus-Tsuga Stage (170-150 cm) IV. Zone R II (ca. 9,000-4,000 years B.P.) 4. Fagus-Quercus-Tsuga Stage (150-100 cm) 5. Cyclobalanopsis-Alnus-Abies Stage (100-70 cm) 6. Cyclobalanopsis-Alnus-Cryptomeria Stage (70-30 cm) V. Zone R III (ca. 4,000 years B.P.-Present) 7. Pinus-Cyclobalanopsis-Cryptomeria Stage (30-0 cm).
The windward slope in the vicinity of Mt. Hinokiodake which is composed of Granite is almost all covered with Pinus pumila scrub and wind-blown dwarf shrub-herb heath emerges only in a few places along the main ridge. To explain the distribution of these plant communities, habitat conditions were examined. Present and past periglacial debris supply processes are related closely to these conditions.
Crinum asiaticum var. japonicum is one of the most famous maritime plants in Japan. Studies on the distribution of this species have been made by many authors, but its ecology has scarcely been described. This study was carried out to obtain ecological and phytosociological information on Crinum asiaticum var. japonicum community. This community usually develops on the stable sandy or shingly coast with some amount of organic matter. As a result of the investigation, a new association including two subassociations was described.
Ecological observations on Ceratina bees were made on the campus of Kanazawa University from 1975 to 1977. The three co-existing species C. japonica, C. flavipes and C. iwatai were mutually similar in flower visiting and preferences of nesting substrates and nesting sites. Their interspecific relationship seems mainly to be governed by the differences in body size and start of nesting activity, which enable in combination a differential use of nesting substrates of different inner diameters.
Distribution of Ceratina bees was surveyed at various localities in Ishikawa prefecture from 1974 to 1977. Five species, C. japonica. C. flavipes. C. megastigmata, C. esakii and C. iwatai were obtained. C. japonica is distributed from the coastal zone up to 1500 m alt., C. flavipes and C. iwatai from the coastal zone up to 500 m alt. whereas C. megastigmata and C. esakii from 500 m to 1500 m altitude. In Mt. Iozen, three species, C. japonica, C. megastigmata and C. esakii, showed segregation in the use of nesting substrates according to body size, as already found among C. japonica, C. flavipes and C. iwatai on the campus of Kanazawa University. The interspecific relation among five species seems to be governed, to some degree, by this differential use of substrates linked with body size, nesting period, and altitudinal segregation between two medium species (megastigmata and flavipes), as well between two small species (esakii and iwatai).