Lowland forests of western Amazonia contain the most species-rich primate communities in the Neotropics, which begs the question of what mechanisms operate to promote species coexistence. This study examines habitat occupancy and its relationship to phylogeny in a primate community in Amazonian Ecuador. First, as potential factors that shape community structure, we determined whether (1) mean height in the forest canopy differed among species; (2) within each species, habitat occupancy was disproportional to habitat availability; and (3) species diverged in habitat occupancy. We then tested hypotheses regarding ecological distance and its relationship to phylogenetic distance among species pairs within this community. We tested these hypotheses primarily with data derived from 15 censuses of primate species on two 100-ha plots in eastern Ecuador. In these censuses, we observed eight primate species over nearly 200 encounters. We observed larger species at greater heights in the forest canopy than smaller ones. Although they occupied habitat types at frequencies proportionate to their availability in the study area, species diverged in habitat occupancy. Although a clear relationship was not observed between phylogenetic and ecological distances among species pairs, this study suggests that ecological differences among the species in this community facilitate their coexistence.

Several South-East Asian anuran species can breed year-round near the equator (due to abundant rainfall in all months in Singapore, for example) but are limited to a 6-mo breeding season in other areas (including central Thailand). In order to investigate the extent to which such differences in breeding season length are associated with differences in reproductive measures such as clutch size, reproduction of three common species, Polypedates leucomystax, Microhyla heymonsi and Hylarana erythraea, was compared in Singapore and Thailand over a 2-y period. All three species produce nearly twice as many eggs per clutch in seasonal environments compared with aseasonal environments, although annual fecundity may be similar in both environments. In Polypedates leucomystax, increased clutch size and volume are associated with larger female size, but in the other two species female size is unchanged with respect to latitude. In H. erythraea, the increased clutch size in Thailand was observed early in the breeding season; later clutches were not significantly different between sites. Collectively, these data suggest that these widespread species have adapted to shortened breeding season length by increasing clutch size.

Temporal niche partitioning can be a viable mechanism for coexistence, but has received less attention than other niche axes. We characterized and compared patterns of activity, and overlap of temporal activity among the five common rodent species from a tropical semideciduous forest (TSF) and between the two common rodent species from cloud forest (CF) at El Cielo Biosphere Reserve in Mexico. Capture frequencies over 2-h intervals, obtained via live trapping (6850 trap-nights) in chosen months over 3 y formed the empirical basis for analyses. Trap transects were set from 19h00 to 07h00 and checked every 2 h. Analyses of 484 captures evinced two distinct assemblages. The TSF assemblage was diverse and with non-random temporal niche segregation, whereas the CF assemblage was depauperate with its two dominant species evincing the same activity pattern. Predator avoidance between open- and closed-microhabitat species, as well as niche complementarity may explain temporal segregation at TSF. This is the first documentation of assemblage-wide non-random temporal segregation of neotropical rodents. Time of activity may be a largely under-appreciated mechanism in other species-rich tropical rodent assemblages as well as in other species-rich biotas.

Population structure and dynamics of the black-cheeked gnateater (Conopophaga melanops) were studied at Salto Morato Nature Reserve, in Paraná, southern Brazil, from October 2006 to September 2007. Territory size and population density, breeding season (timing and length), reproductive success and annual survival rates were estimated from sightings of 18 marked adult birds and the success of 18 nesting attempts. The black-cheeked gnateater is socially monogamous and territorial, with a breeding-season length of approximately 3 mo beginning in early October. Predation caused most nest failures, nest survival was 0.96 d−1 and apparent annual nesting success was 22%, resulting in annual productivity of 0.36 individuals per adult. Apparent adult annual survival was ~0.44 y−1. Seventy-five per cent of fledglings survived at least 2 mo after fledging. Two methods of estimating population growth rate suggest very different rates: r = −0.04 (~ stable), or λ varies between 0.475–0.616 (declining). Yet, low apparent adult survival suggests that territories are not permanent, perhaps abandoned after nest failure. We find that by estimating population growth, even in short-term studies, testable hypotheses can be generated that will allow better understanding of population dynamics.

A sample of 1834 leaves from 83 plants in 26 families was collected in tropical rain forest in Madagascar from three vertical strata: top of emergent trees (up to 37 m), top of trees in upper canopy (about 22 m), and shrubs and saplings at ground level. These leaves were examined for damage by seven different agents: fungi, epiphyllae, mechanical injury, galls, leaf miners, grazing insects and skeletonizing insects. Fungi affected more than 60% of the leaves and grazing insects 45–65%, with other agents each affecting 3–30%; fewer than 4% of the leaves escaped unscathed by any agent. Individual leaves were attacked by up to five agents. There was a sharp decline in proportion of leaves affected by fungi, leaf miners, epiphyllae and mechanical breakage with increasing category of severity. Grazing insects, mechanical injury, and perhaps galls, had greater impact at ground level than in the canopy, with fungi and skeletonizing insects showing the opposite pattern. Leaf miners had lower incidence in the canopy than elsewhere. The observed vertical stratification means that a tree not only needs to balance its defences to meet multiple threats in any stratum, but must adapt to a different suite of challenges during its lifetime. Attack by grazing insects and fungi are major challenges for saplings at ground level, but with increasing height above the ground fungal attack on leaves becomes more prevalent, but attack by grazing insects less so.

The Dipterocarpaceae in South-East Asia are known for their strict mast fruiting. During fruiting, pre-dispersal seed predation by insects contributes to mortality of dipterocarp seeds. We documented the community structure of insect seed predators on 11 Shorea species in Peninsular Malaysia. Fruits were sampled sequentially throughout seed development, and 2144 and 1655 individuals of seed predator weevils and moths were collected in two mast-fruiting events. Four weevils: Nanophyes shoreae, nanophyid sp. 1, Alcidodes dipterocarpi and Alcidodes humeralis, and one moth Andrioplecta shoreae were abundant in seeds of the Shorea species. The proportion of N. shoreae to the total predators became larger in the latter fruiting event than the former while that of Alcidodes spp. became smaller. The predator species composition changed during seed development; nanophyid spp. emerged from immature fruits while Alcidodes spp. emerged from mature fruits. Andrioplecta shoreae emerged from both immature and mature fruits. The level of host specificity measured by Kullback–Leibler distance was low for most predator species in both events. Predator species composition of many Shorea was similar to each other due to the dominance of N. shoreae though it might gradually differ with the phylogenetic distance between hosts. In conclusion, predator species composition of Shorea varied during seed development within a host rather than among hosts. Intermittent synchronized fruiting by congeneric Shorea trees would be advantageous to avoid pre-dispersal insect seed predators, and contribute to their reproduction.

To evaluate N limitation on above-ground net primary production in a tropical lower montane rain forest, an N fertilization experiment was conducted for 2 y. The study site is located at 1200–1300 m asl in the Fortuna forest reserve in western Panama and has a mature, mixed-species stand growing on an Andisol soil. Control and N-fertilized (125 kg urea-N ha−1 y−1) treatments were represented by four replicate plots (each 40 × 40 m, separated by at least 40 m). Stem diameter growth was analysed by diameter at breast height classes and also for the three most abundant species. The three species did not respond to N addition. The response of stem growth and above-ground woody biomass production to N fertilization varied among dbh classes. Stem growth of trees of 10–30 cm dbh increased only in the first year of N addition while trees of 30–50 cm dbh responded in the second year of N addition, which may be due to differences in light conditions between years. Trees >50 cm dbh did not respond during 2 years of N addition. As a result, the overall stem growth and above-ground woody biomass production were not affected by N fertilization. Annual total fine litterfall increased in the first year of N fertilization, while annual leaf litterfall increased in both years of N addition. Above-ground net primary production, of which total fine litterfall constituted 68%, also increased only in the first year of N addition. The magnitude and timing of response of stem diameter growth and litterfall suggest that these aspects of above-ground productivity are not uniformly limited by N availability.

Understanding how wood decomposition varies spatially at the mesoscale (between 1-ha plots) may improve carbon flux estimates in Amazonian forests. An experiment was carried out to test the influence of soil, slope, above-ground tree live biomass (biomass), fine-litter mass and characteristics of neighbouring trees on the variation of wood decomposition between 1-ha plots in four species of tropical trees that vary in wood density (Manilkara huberi – 0.86 g cm−3, Couratari guianensis – 0.54 g cm−3, Hura crepitans – 0.32 g cm−3 and Parkia pendula – 0.29 g cm−3). A wood sample from each species (30 × 5 × 2.5 cm) was placed in each of 71 plots within 64 km2 of terra firme tropical moist forest in Reserva Florestal Adolpho Ducke. One year later, samples were collected and weighed. The effects of specificity of decomposers was measured by the association of decomposition with the wood density and with the taxonomic group of the nearest tree with dbh ≥30 cm. Wood decomposition was independent of soil (texture and nutrients), slope, biomass and fine-litter mass at the mesoscale, except for C. guianensis, which showed greater decomposition in locations with greater biomass. Decomposition was also independent of wood density and taxonomic group of nearby large trees. In general, none of the variables was useful as a predictor of wood decomposition at the scale larger than 1 ha. Thus, the use of models that include soil and topography to improve estimates of carbon flux are limited because wood decomposition does not follow similar mesoscale patterns to that of biomass and fine-litter decomposition. Also, the results indicate that wood decomposition is more likely to be associated with generalist decomposers than with specialists associated with neighbouring trees.

Litter decomposition is a fundamental process for nutrient cycling but we have a limited understanding of this process in disturbed tropical forests. We studied litter decomposition over a 10-mo period in a seasonally dry Amazon forest in Mato Grosso, Brazil. The study plots (50 ha each) included unburned forest (UF), once-burned (BF1) and forest burned annually for 3 y (BF3). We measured understorey density, litter depth, canopy openness, temperature and relative humidity in the plots. Decomposition experiments took place using 720 litterbags filled with approximately 10 g of natural abscised oven-dried leaves. To test the effects of fire on soil meso- and macrofauna, the litterbags had either a fine (2 mm) or coarse (with 1-cm holes in side) mesh size. Litterbags were collected and reweighed 2, 4, 6 and 8 mo after being placed on the forest floor. All forest structure variables were significantly different across plots: BF3 was hotter, less humid, had the highest degree of canopy openness, lowest understorey density and the shallowest litter depth. Litter decomposition (mass loss) was similar in the once-burned and unburned plots, but declined more slowly in BF3. In addition, decomposition was slower in fine-mesh litterbags than coarse-mesh litterbags in BF3, but there was no difference between mesh sizes in BF1 and UF. It is likely that changes in forest structure and microclimate explain the lower decomposition rates in BF3. These results show the importance of recurrent fires, but suggest that single understorey fires may not have long-term negative effects on some ecological processes in seasonally dry Amazonian forests.

Litter standing crop (LSC) is the quantity of plant detritus on the floor in forested environments. Knowledge of LSC is important in understanding many ecological phenomena. These include studies of litterfall, decomposition/litter turnover rates and nutrient cycling (Anderson et al. 1983, Dent et al. 2006), general plant performance (Benítez-Malvido & Kossmann-Ferraz 1999), other ecosystem processes such as the effects of fire (Odiwe & Muoghalu 2003) and fauna (Frith & Frith 1990, Giaretta et al. 1999, Levings & Windsor 1985). The determination of accurate annual average LSC data, may require monitoring over long periods due to seasonality and sometimes sporadic nature of litterfall and decomposition rates (Clark et al. 2001). Furthermore, the effects of topography and water movement create the need for both representative site selection and sufficient spatial coverage.

Spatial organization within animal populations is often thought to reflect the outcome of strategies implemented by each individual to enhance its reproductive success and survival (Clutton-Brock 1989). Thus, while females usually focus on the acquisition of food and breeding sites, male dispersion is more often determined by the distribution and availability of females (Clutton-Brock 1989). Due to these factors, intraspecific competition for space could lead to the adoption of a territorial strategy, whenever the benefits of territorial defence are higher than the costs (Brown & Orians 1970). Among small mammals, two main hypotheses have been proposed to explain the occurrence of territoriality in females. Ostfeld (1990) proposed that females should defend food resources, so the distribution and availability of food items should determine the cost–benefit relationship of adopting a territorial strategy. However, Wolff (1993) developed a hypothesis, based on small rodents, that females should defend nest sites in order to avoid infanticide, the so-called pup-defence hypothesis.

With increasing conversion of South-East Asian forests to human-dominated landscapes, dramatic changes in biodiversity are likely to have ramifications on ecosystem processes (Sodhi & Brook 2006). Dung beetles (Coleoptera: Scarabaeidae) have been used to investigate how biodiversity changes affect ecosystem functions (Larsen et al. 2005, Slade et al. 2007). Dung beetles provide important ecosystem services such as dung removal and secondary seed dispersal (Nichols et al. 2008) and have been shown to be reliable indicators of tropical forest disturbance (Gardner et al. 2008, Klein 1989). Here, we determine the effects of forest disturbance on the species richness of dung beetles and ecosystem functions they perform in Peninsular Malaysia and Singapore. As far as we know, there has been no known study published on dung beetle ecology on the Malay Peninsula. In this study, we test the hypothesis that old-growth forests contain dung beetle communities of higher species richness, abundance, biomass and larger body size. Previous studies have shown that changes in dung beetle communities have the potential to disrupt ecosystem services in natural habitats (Larsen et al. 2005, Mittal 1993). We also investigate whether dung removal is affected by forest disturbance and test the hypothesis that dung removal is reduced in more disturbed forests compared with less-disturbed forests.