A phytosociological study of mantle communities was made in the Nansei Islands, southwestern Japan. As a result, 5 associations and 2 communities were classified. These vegetation units were contained in 2 alliances : Clerodendro-Derriion trifoliatae and Aristolochio-Clematidion ryukyuensis. The Clerodendro-Derriion trifoliatae is a tropical mantle community, and it occurs in the coastal areas of most of the Nansei Islands, especially in mangrove forest regions. The Clerodendro-Derriion trifoliatae includes 2 associations dominated by evergreen erect-type shrubs. Aristolochio-Clematidion ryukyuensis on the other hand is an endemic mantle community of the Nansei islands, and it occurs around many types of forest vegetation, e.g. natural Castanopsis cuspidata var. sieboldii forest and Leucaena leucocephala forest, in lowlands and mountain areas. The Aristolochio-Clematidion ryukyuensis includes 5 vegetation units, 1 association dominated by Rubus-type shrubs and 2 associations and 2 communities dominated by vines. Mantle communities in the Nansei Islands, as a whole, contain many evergreen vines, and are characterized by endemic species as well as tropical species. Their species combination differs from other northern areas of Japan.
Forest dynamics of an evergreen oak (Quercus acuta) forest were studied in the Kannami Virgin Forest, Central Japan, as part of a regionally comparative study of warm-temperate forest dynamics. And consequently, a regeneration complex was clarified. The complex was composed of four sequential phases : gap, building, mature, degenerate, and sub-types of these phases. Based on densities of tall-tree species in each layer of each community type and on the structure of each community type, two typical sequences of micro-succession were estimated. One is from the "under layers remaining type" gap phase through the building phase, the canopy of which is dominated by evergreen broad-leaved tall-tree species, to the evergreen broad-leaved type mature phase. The other is from the "all layers collapsed type" gap phase through the building phase, the canopy of which is dominated by summer-green broad-leaved tall-tree species, to the summer-green broad-leaved type mature phase. This type of forest dynamics, a co-existing pattern of warm-temperate evergreen oak and temperate summer-green broad-leaved tall-tree species, may prevail in distribution fringes of evergreen broad-leaved forests.
The vegetational zonation of sandy coasts in the San in District was studied in relation to depositional topography. The vegetation was divided into four zones (Z1-Z4). The first (Z1) was pioneer zone where only young plants were found in places. The second (Z2) was of grass communities which were divided into two subzones (Z2-a, Z2-b). Carex kobomugi was a dominant of Z2-a and Ischaemum anthephoroides of Z2-b. The third (Z3) was occupied by scrub demarcated by dominant growth of Vitex rotudifolia, and the fourth (Z4) was represented by plantations of Pinus thunbergii and Robinia pseudo-acasia. The Izumo coast faces north-west and receives prevailing NW-wind in winter and sand dunes develop. As dune height increases, Z2-a becomes narrower and Z2-b becomes wider. The Yumigahama coast, however, does not have prevailing winds in its front, so that dunes do not develop to make flat topography. The vegetation was found far from the shore-line. The Hojyo coast has well-developed dunes which are comparatively stable, because of the coarse beach sediments, leeward place and snow accumulation in winter. On the stable dune the narrow grasses of Z2 zone and Artemisia capillaris and Heteropappus hispidus var. arenarius on the third zone (Z3) were commonly found. The relationship between the zonation of the dune vegetation and topography was discussed with respect to the prevailing winds and the particle of the beach sediments.
To clarify the possible mechanisms controlling the distribution of Fimbristylis cymosa subsp. umbellato-capitata (FCU) in the coastal windswept pasture, field experiments using protective cages at 0 m, 200 m, 300 m and 400 m from the cliff top were carried out in Yonaguni Island, Southwestern Japan. Ecological characteristics of FCU were investigated under different field conditions. Seedlings of FCU were cultivated in sand containing different amounts of NaCI under shading conditions in a greenhouse. In the field the mean clone size inside the enclosure was bigger than that outside. The size of the clones transplanted in the enclosures near the cliff top increased, but those inside and outside the enclosure located further from the cliff edge died. The growth of FCU cultivated in the greenhouse was suppressed at a high NaCl concentration ; however, the dry weight of unshaded plants increased. While under shaded conditions, plants scarcely grew even without addition of NaCl. FCU was distributed around the sea cliff with and without grazing use. However, in sheltered places where salt winds decline, the number of plant species increased and growth of FCU was suppressed by tall-growing Imperata cylindrica under protected, and by quickly expanding prostrate species e. g. Digltaria under grazed condition.
Deciduous broad-leaved trees were severely damaged by the 1977 eruption of Mt. Usu. The degree of damage, however, was different among tree species. In intermediately disturbed sites, many trees of excurrent growth species (e. g., Populus maximowiczii) produced a few epicormic sprouts, but almost all trees died within 3 years after the eruption. Conversely, many decurrent growth species (e. g., Acer mono) showed active epicormic sprout development and consequently survived for at least 8 years. Survivors gradually decreased their heights by consequence of withering their epicormic sprouts at their tops. Such responses are perhaps accomodative to the condition of being deeply buried by volcanic deposits and therefore restricted on water absorption as well as results of severe stress. In addition, such responses are closely related to the growth habit of decurrent growth species characterized by weak apical control, therefore, it was suggested that the stem survival potential of excurrent growth species to volcanic deposits should be extremely constrained by weak apical control, therefore, it was suggested that the stem survival potential of excurrent growth species to volcanic deposits should be extremely constrained by their own tree architecture characterized by strong apical control.
The spool-and-line method, which had been used for animal tracking, was improved and applied as a new quantitative technique to investigate seed dispersal by rodents. The advantages of this method are that caches and routes of rodents can be found efficiently. To recognize behavior of rodents, it is important that the traces from a bait box to a cache can be confirmed. Using oak acorns (Quercus mongolica var. grosseserrata) with a spool, the distance of secondary dispersal by Apodemus spp. was investigated in a pine forest. Acorns were cached at the distance of 0.6-9.5 m (mean 3.02 m, SD=2.51,n=14) from bait boxes. The depth of the caches under the soil surface were recorded.
A variety of the social system in the Canidae was reviewed with the comparison of mating system, social behaviour, and feeding ecology in the context of evolutionary perspective. Five types of social system were identified according to the periods of pair formation, the degrees of paternalmaternal care and the dipsersion patterns of offspring. In types I to III, a male-female pair is the basic social unit of the system accompanied with their offspring and/or non-dispersal offspring. Types IV and V are unique, compared with the former three, while their basic social unit is also the mating pair. Canids used a wide variety of food items from berries to large mammals ; this was caused by their opportunistic feeding strategies to the change of resource availability. The longterm monogamous mating system among canids would have evolved through a trait that males are less successful with two mates than with single, in their physiological constraint of reproduction. Canids social systems varied also by the utilization patterns of resources among parents and their offspring.
In this review, effects of various environmental factors on photosynthesis of higher plants are discussed, using reported results. The methods for the estimations of photosynthetic rates, conductance for water vapor diffusion, and the evaluation of intercellular concentration of CO2 are also described. Major environmental factors such as light, temperature, CO2,water, and air pollutants are related to photosynthetic efficiency from the aspect of ecophysiological significance. The applications of physical or mathematical equations are proposed for analyzing the effects of these environmental factors on photosynthesis.