The altitudinal zonation of forests on Mount Kerinci, Sumatra (3800 m) is described and compared with that in the temperate region of east Asia. Nine plots were selected between 1750 m in altitude and the upper limit of vegetation at 3250 m, at intervals of about 200 m in altitude. The plots are distinguished according to their main dominants, and the population structure of the dominant species is examined. The lower forests have species showing the whole range of size classes as well as solitary giants as dominants, but the upper forests lack these giants and are floristically poorer. Between 1750 m (the start of well preserved natural vegetation) and 2950 m (the forest limit) three forest zones are distinguished, and between 2950 and 3250 m a scrub zone. Upper forest zones tend to be dominated by species of the same genus or family which form important understory components of the zone below. Based on floristic comparisons with mountains of higher latitudes (i.e. Himalayas and Japan), the two lower forest zones (up to 2400 m) represent a subtropical zone, and the upper forest zone a warm-temperate zone. Climatic conditions at the forest limit on Mount Kerinci are similar to those at the latitudinal limit of warm-temperate evergreen trees; in the Himalayas the forest limit represents the latitudinal limit of the cool-temperate, and in Japan of the subarctic Altitudinal zonation patterns change with latitude, reaching their most complex on subtropical mountains where the two floristic realms, the Boreal and Palaeotropical, meet. A scheme for the pattern of vegetation zonation in east Asia is proposed.

Estimates were made of rodent longevity, population biomass and production in a dry sub-humid grassland area in Kenya, The results were based on a live-trapping study made over a 27-month period. During this time fourteen species of rodents and four species of insectivores were recorded from the area of the trapping grid. The most numerous species were Praomys natalensis, Mus triton, Mus minutoides and Lemniscomys striatus.

Breeding took place in both wet seasons, coinciding with peaks in rodent populations. Densities ranged from 6.6 ha-1 to 52.4 ha-1, and estimates of net annual production varied from 5485 g ha-1 year-1 to 7221 g ha-1 year-1. Rodent populations appear to turn over every six to nine months.

The results are discussed in relation to studies in other tropical grassland areas of Africa.

The general flowering of lowland dipterocarp forests of South-east Asia is a unique phenomenon that occurs intermittently, sometimes many years apart, and may be widespread throughout the region or sporadic. During a general flowering a very large number of tree families, including the well-known Dipterocarpaceae, flower and fruit exceptionally heavily. The huge pulse of flowering is echoed by an apparent explosion in the number of pollinators, and this is further augmented by migration of pollinators from the forest fringes. The huge demand for pollinators seems to be solved among several dipterocarps through utilization of tiny, fast breeding, floral-feeding insects such as thrips and hoppers. Competition for pollinators is further reduced through development of sequential flowering among several groups of trees that share similar pollinators. The resulting massive general fruiting seems to contribute to a heightened level of faunal activity and numbers. This long-intervalled flowering and fruiting phenology which dominates these lowland dipterocarp forests may have partly contributed to the lowered animal biomass frequently alluded to when these forests are compared with neotropical forests.

Artibeus watsoni (Chiroptera: Phyllostomidae) was found in Costa Rica to alter the shape of 11 species of broad-leafed plants in the families Araceae, Cyclanthaceae, Maran-taceae, Musaceae, and Palmae to form diurnal roost sites. The plant most commonly used for tent construction was Anthurium ravenii (Araceae). Bats create a tent on A. ravenii by severing the basal 2 to 5 lateral nerves at a distance of 5 to 10 mm from the midrib; the entire margin of the leaf then collapses downward to form a pyramid-shaped tent. The number of altered leaves per plant ranges from 1 to 4 with a mean of 2.1. A. watsoni appears to be selecting leaves of medium size and low within the plant. The size, shape, and location of leaves selected is consistent with the hypothesis that tent construction provides bats with roost sites that will be available to them for a long period of time and provides protection from both predators and the elements, thus conveying a selective advantage to the bats.

Seasonal variations in the breakdown and dynamics of chemical elements in Ficus fistulosa leaves in a mixed forest on Hong Kong Island were investigated between October 1982 and September 1983. Mean rate of leaf material weight loss from coarse-mesh (3 mm) bags was 1.82% day-1, about four times that inside fine-mesh (0.2 mm) bags (mean rate 0.44% day-1). Breakdown rates varied seasonally with maximum rates in spring or summer, and were significantly correlated with prevailing temperatures, the rainfall of the two previous months, and the soil moisture content of the previous month. Potassium and Mg were rapidly leached from leaf material throughout the year while the concentrations of C, N, P, Ca and Na remained relatively stable. In the absence of macrofauna (inside fine-mesh bags) decomposition rate constants (k) were positively correlated with the mean abundance of mites and Collembola, as well as with total invertebrate abundance. In the presence of macrofauna (inside coarse-mesh bags) decomposition rate constants were positively correlated with isopod and amphipod abundance. There was no significant correlation between breakdown rates of leaf material and mesofaunal abundance inside coarse-mesh bags. The importance of climate and invertebrates as rate determinants of Ficus decomposition is discussed.

Large areas of the Himalayas have become severely deforested although little has been published about the extent of this problem in the closed Kingdom of Bhutan. A preliminary survey was undertaken during 1983. Without detailed information or accurate maps, LANDSAT 2 imagery was used to prepare a sampling stratification and to plot the distribution of defined vegetation types after sampling and analysis. Eleven forest noda are described in relation to their habitats, and area and timber volume estimates given. Deforestation pressures are discussed.