To investigate changes in vegetation and climate with altitude, we established forest plots and recorded climatic data at 100-m intervals between 550–1100 m asl on the western slopes of Mount Batilamu, Mount Koroyanitu range, Viti Levu, Fiji. Trees with a dbh ≥10 cm were identified and measured in 21 10 × 10-m plots, starting at 750 m altitude. Temperature and relative humidity sensors were deployed in two habitats, leaf litter and 50 cm above the ground, and two vegetation types, grasslands and forest, at six altitudes over a 48-h period. Two significantly distinct forest types, lowland and montane, were present. Montane forest was found at higher elevations (>950 m asl) and had significantly higher stem density. Mean temperature decreased significantly with altitude and was strongly moderated by vegetation type (lower average and less variation in forest). While average relative humidity significantly increased with altitude, it was strongly moderated by both habitat and vegetation type (higher average and less variation in leaf litter and forest). The lapse rate varied with time of day (higher during the day) and vegetation type (higher in grasslands). Therefore, vegetation and microhabitats create unique microclimates, and this should be considered when investigating current or future climatic patterns along altitudinal gradients on forested mountains.

Long-term forest dynamics plots in the tropics tend to be situated on stable terrain. This study investigated forest dynamics on the north coast of New Guinea where active subduction zones are uplifting lowland basins and exposing relatively young sediments to rapid weathering. We examined forest dynamics in relation to disturbance history, topography and soil nutrients based on partial re-census of the 50-ha Wanang Forest Dynamics Plot in Papua New Guinea. The plot is relatively high in cations and phosphorus but low in nitrogen. Soil nutrients and topography accounted for 29% of variation in species composition but only 4% of variation in basal area. There were few areas of high biomass and most of the forest was comprised of small-diameter stems. Approximately 18% of the forest was less than 30 y old and the annual tree mortality rate of nearly 4% was higher than in other tropical forests in South-East Asia and the neotropics. These results support the reputation of New Guinea's forests as highly dynamic, with frequent natural disturbance. Empirical documentation of this hypothesis expands our understanding of tropical forest dynamics and suggests that geomorphology might be incorporated in models of global carbon storage especially in regions of unstable terrain.

Recent observations from the tropics indicate seasonal peaks in breeding and vocal activity of some bird species. However, information about seasonality in vocal activity at the community level is still lacking in the tropics. We examined seasonal variation in the diurnal vocal activity of lowland rain forest birds on Mount Cameroon, using weekly automatic sound recording throughout the whole year and related it to rainfall and temperature. We show that the bird community in lowland rain forest vocalized year-round, but species richness as well as the vocal activity of the community varied greatly during the year. This variation coincided with the seasonality of rainfall. The highest number of species (31.5 on average) sang at the beginning of the driest period, followed by a gradual decrease in singing with increasing rainfall (minimum 14.5 species). This indicates that intensive rainfall indirectly limits the vocal activity of the tropical rain-forest bird community. Temporal turnover of vocalizing species as well as within-day variation in vocal activity was highest during the transition period between dry and rainy seasons. We suggest that this could reflect differing timing in the breeding activity of particular feeding guilds to follow seasonal peaks of their diets.

Volcán Barva, Costa Rica, has on its northern slope an unbroken sequence of rain forest on volcanic parent materials from near sea level at La Selva Field Station up to its summit at 2906 m. It provides a good area to study forest changes with altitude and their causes. In the present paper we describe the forests as a background for soil and litterfall studies from 1 ha plots at each of the following altitudes: 100 m, 500 m, 1000 m, 1500 m, 2000 m and 2600 m. The canopy heights (with height of the highest emergent in parentheses) ranged from 35–40 m (45 m) at 100 m to 20–23 m (32 m) at 2600 m; basal area was least (22.7 m2) at 100 m and highest (51.2 m2) at 2600 m; the tree (≥10 cm dbh) density ranged from 391 ha–1at 500 m to 617 ha–1 at 2600 m. Most trees were identified and on samples of them we recorded presence of buttresses, lianes, skiophytic climbers, vascular epiphytes and bryophytes; and drew profile diagrams. In the classification of Whitmore (1984) the two lower plots are evergreen lowland rain forests; the other four are lower montane rain forest. Species richness was highest in the plot at 500 m, with at least 135 species of tree, and least at 2600 m, with at least 35 species. The Volcán Barva forest altitudinal sequence is briefly compared with those elsewhere.

A total of 392 small mammals belonging to five species of small rodents and four species of shrews were caught. The small mammals and their percentage composition were Crocidura nigeriae (20.9%), Crocidura grandiceps (11.7%), Crocidura crossei (9.7%), Crocidura flavescens manni (20.4%), Mus musculoides (39.0%), Praomys tullbergi (11.5%), Lophuromys sikapusi (3.6%), Lemniscomys striatus (1.3%), and Arvicanthis niloticus (0.3%).

There were monthly variations in the number of Mus musculoides and Crocidura nigeriae.

In Mus musculoides breeding was at a maximum at the beginning and towards the end of the wet season and early dry season. In Crocidura nigeriae breeding was maximal during the wet season and low in the dry season.

The seasonal changes in the age structure of the two most common species: Mus musculoides and Crocidura nigeriae, are described.

Few studies have been conducted to investigate ecological roles of litter amphibians in forest ecosystems. In this study, ten field enclosures (3 m × 2 m × 0.4 m) were used to evaluate effects of the toad Bufo bankorensis on the abundance of litter invertebrates (microbivores, fragmenters and predatory arthropods) and litter decomposition rates in a subtropical forest of southern Taiwan. Litterbags collected from toad and control (toad-excluded) enclosures were analysed for the communities and abundances of litter invertebrates and decay loss during this decomposition study from September to December 2001. The presence of B. bankorensis significantly changed phosphorus concentrations in the litter, but not the densities of litter invertebrates (microbivores, fragmenters and predatory arthropods) or rates of litter decomposition. These results were not consistent with previous studies, which have shown that Plethodon cenereus in a temperate forest of north-east USA and Eleutherodactylus coqui in a tropical rain forest of Puerto Rico significantly changed decomposition rates. We suggest that ecological roles of ground-dwelling amphibians may be species-specific and vary with different terrestrial ecosystems.

Porina pilifera Neuwirth sp. nov. is described from Costa Rica. It is similar to P. palmicola, but differs in having smaller ascospores 27–36×3–4 μm. Porina pilifera is only known from the type locality in tropical Central America, where it grows on the leaves of palm trees.

Local species richness and between-site similarity in species composition of parasitoid wasps (Hymenoptera: Ichneumonidae; Pimplinae and Rhyssinae) were correlated with those of four plant groups (pteridophytes, Melastomataceae, Burseraceae and Arecaceae) in a western Amazonian lowland rain forest mosaic. The mosaic structure of the forest was related to variation in soils within the non-inundated terrain. Significant matrix correlation between patterns in parasitoid wasp species composition and plant species composition was found. Most of the overall correlation was due to idiobiont parasitoids of weakly concealed hosts, which attack host larvae and pupae in exposed situations, with two of the four ecologically defined parasitoid groups showing no correlation at all. A positive correlation between the number of plant species and the number of Pimplinae and Rhyssinae species at a site was found when the latter was corrected for collecting effort. Consequently, the degree of floristic difference between sites may be indicative of the difference in species composition of ichneumonids, and the species richness of plants may serve as a predictor of the species richness of parasitoid wasps. Although these results were obtained in a mosaic including structurally and floristically clearly different types of rain forest, the correlation coefficients were relatively low, and the present results lend only weak support to the idea of using plant distributions as indicators of animal distributions.

All dead trees ≥ 20 cm DBH were counted in the first 6 mo of 1994 in 10 ha of wet lowland rain forest, in the Hoja Blanca Hills, western Ecuador. The trees were classified by their mode of death. Thirty-four per cent of the trees were uprooted, 35% had snapped, 15% had died standing and 16% were unclassified. Regression analyses found that slope position and whether an individual was a dicotyledonous tree or a palm (Iriartea deltoidea) to be both strongly related to the mode of death. Slope, altitude and the presence of buttresses also influenced the mode of tree death. Tree diameter, however, was not found to have any effect. Dicotyledonous trees predominantly uprooted and snapped while Iriartea mostly died standing and snapped. Uprooted and snapped trees were significantly spatially clumped while trees which died standing were distributed at random. It was concluded that the predominance of uprooting and snapping in Hoja Blanca mostly resulted from the steep terrain and high precipitation (c. 5000 mm y−1) as well as El Niño Southern Oscillation (ENSO) downpours. The implications of mode of death are discussed. The different modes created different types of gaps and could thereby potentially influence forest regeneration.