The relationship between herbivore diet quality, and diet composition (the range of food plants consumed) and body mass on resource partitioning of herbivores remains the subject of an ongoing scientific debate. In this study we investigated the importance of diet composition and diet quality on resource partitioning among eight species of savanna herbivore in north Cameroon, with different body mass. Dung samples of four to seven wild herbivore and one domesticated species were collected in the field during the dry and wet period. Diet composition was based on microhistological examination of herbivore droppings, epidermis fragments were identified to genus or family level. In addition, the quality of the faecal droppings was determined in terms of phosphorus, nitrogen and fibre concentrations. The results showed that there was no significant correlation between body mass and (differences in) diet composition for wet and dry season. When all species are considered, only significant relationships are found by the Spearman rank correlation analyses during the wet season between body mass and phosphorus and nitrogen, but this relationship did not exist during the dry season. When the analyses focuses on ruminants only (thus leaving out hippo), none of the relationships between body mass and diet quality was significant in either season. During the dry season the proportion of graminoids ranged between 10% (small unidentified herbivore species) to 90% (hippopotamus), during the wet season this proportion ranged from 60% (zebu) to 90% (hippopotamus). All species but zebu had more graminoids in their dung during wet season compared with dry season. However all species but hartebeest had more graminoids old stems in their dung during the dry season, compared with the wet season. The niche breadth for food categories consumed by kob (0.300), hippo (0.090), hartebeest (0.350), roan (0.510) and zebu (0.300) was much greater in the dry season than in the wet season for kob (0.120), hippo (0.020), hartebeest (0.190), roan (0.090) and zebu (0.200). When looking at grass taxa consumed, the niche breadth of kob (0.220), hartebeest (0.140), and roan (0.250) was also greater in the dry season when compared with the wet season for kob (0.050), hartebeest (0.120) and roan (0.120). The opposite was found for zebu and hippo. Comparison of the species’ diet compositions with randomized data showed that dietary overlap between different herbivore species was much higher than what would be expected on the basis of chance, demonstrating surprisingly limited niche separation between species. This offers potential for competition, but it is more likely that the high niche overlap indicates absence of competition, due to low herbivore densities and abundant food resources, permitting species to share non-limiting resources. With increasing herbivore densities and subsequent increasing scarcity of resources, the relationship between diet quality and body mass in combination with increased niche separation is expected to become more visible.

Reproduction by Bolomys lasiurus is strongly seasonal in the Amazonian savanna of Alter do Chāo, Pará, Brazil. No pregnant or lactating females were recorded during the early dry season (July-September). Relative growth rates showed a similar though less consistent pattern. These patterns do not appear to be due to a direct effect of rainfall as high reproduction and growth were recorded during the late dry season (October-November), even though rainfall and the availability of fruits of shrubs were low during that period. It is likely that reinitiation of reproduction during the dry season is due to an increase in the availability of invertebrates and/ or wind-dispersed seeds. Fire at the end of the dry season appears to affect the diet of the rats, causing an increase in the ingestion of invertebrates during the following wet season. However, our data do not indicate that fire affects individual reproductive output or growth.

The ecological importance of trees lasts much longer than their life spans. Standing dead trees (snags) and fallen trunks and branches are an important component of above-ground carbon stocks and nutrient reserves, provide habitat for wildlife, and interact with disturbance regimes (e.g. by serving as fuel for fires) (Clark et al. 2002, Harmon et al. 1986, Pyle et al. 2008). Despite these diverse functions, woody debris stocks remain poorly quantified in tropical forests in general (Brown 1997), and in tropical dry forests in particular (Harmon et al. 1995). More empirical studies of the patterns of woody debris and processes that control its dynamics are needed to understand its role in global biogeochemical cycles and for ecosystem simulation models, many of which do not represent coarse woody debris (CWD) as a separate pool (Cornwell et al. 2009).

The amount and annual net accumulation of above-ground dead woody material were quantified in a tropical deciduous forest in western Mexico. Three plots were located within a small watershed (16 ha) and distributed along a 150-m-elevation gradient (Upper, Middle and Lower plot). Total amount of above-ground dead phytomass (fine + coarse) was 27.2 Mg ha-1. Coarse dead category (branches + logs) made up 70.6% (19.2 Mg ha-1) of the total. The rest comprised the fine fraction, which was lying on the forest floor as surface litter. Of the total coarse dead woody mass, 70.8% was standing, hanging or still attached to live trees (13.6 Mg ha-1). Dead wood net accumulation was 6.6 Mg ha-1 y-1; 58% of this was coarse woody material and the rest comprised the fine litterfall fraction. The amount of standing, hanging/attached dead branches (2-20 cm circumference) varied significantly among plots, with the highest value in the Upper plot. Dead wood net accumulation was similar between the Upper and Middle plots, and significantly higher than the Lower plot. Compared to the intact canopy, the removal of dead mass (hanging/attached dead branches and standing dead logs) caused a significant decrease in throughfall nutrient concentration and nutrient flux by this pathway.

The population dynamics of 8500 shade-tolerant tree seedlings of 13 tree species were followed for 10 years at rain forests in Lambir Hills National Park and Bako National Park, Malaysian Borneo. Since these dipterocarp forests have lower rates of canopy gap formation than do rain forests elsewhere, tree seedling biology was predicted to differ. Approximately 50% of seedlings present in 1986 were still alive in 1996. Seven out of thirteen had seedling populations composed predominantly of individuals that were at least 10 years old. These seedlings can undergo alternating periods of relatively rapid and slow growth. Many seedlings that grew rapidly in the first census interval survived through a period of suppression in the second census interval, and conversely many seedlings with a history of suppression had exceptionally high growth in the final census interval. Seedlings of South-East Asian forest tree species are long-lived and appear to be adapted to long periods of suppression in the understorey.

An investigation of seasonal changes in litterfall in a dense stand of the invasive tropical shrub Mimosa pigra was carried out in northern Australia between October 1984 and December 1986. Total annual litterfall averaged 758 g m−2, close to the value predicted for the latitude and altitude of the site. Leaf litter formed 56.6% of this total, woody material 22.7%, and reproductive material 20.7%. Total litterfall was strongly seasonal, at a maximum in the late wet season or early dry season, and at a minimum late in the dry season. A broadly similar pattern was shown by the various components of the litter, except for woody litterfall, which followed no strong seasonal trend. Variation in the amount of available soil moisture, as calculated from a simple water balance model, accounted for much of the variation in the components of litterfall.

The proportion of all initiated flower heads which produce seeds was estimated to be between 2.1 and 4.5%. The mean annual seed fall was 9103 m−2, nearly two orders of magnitude higher than most native shrub populations, and it is argued that this is partly a result of the absence of natural enemies in the introduced range.

The Amazonian rain forests form one of the largest areas of continuous forest in the world, and they harbour a substantial part of the world's biodiversity (World Conservation Monitoring Centre 1992). The extravagant species richness of Amazonia makes collecting information on species distribution patterns there a formidable challenge. Relatively few studies have been able to provide data that cover both a large enough number of species and wide enough geographical areas to allow relevant biogeographical and ecological generalizations (such studies concerning plants include Balslev 1988, de Oliveira & Daly 1999, Pitman et al. 1999, Prance 1973, ter Steege et al. 2000, Terborgh & Andresen 1998, Tuomisto & Poulsen 1996). The scarcity of field observations is undoubtedly one of the reasons why very different ideas exist about the mechanisms that control plant distributions and patterns of species richness in Amazonia (Balslev 1988, Condit 1996, Gentry 1988, Nelson et al 1990, Pitman et al. 1999, Prance 1973, 1982; ter Steege et al. 2000, Tuomisto et al. 1995).

Observations were made of foraging frequency and food selection by species of Macrotermitinae in a savanna habitat in the distal reaches of the Okavango Delta, Botswana. A removal experiment in the field was also conducted. Observable foraging showed seasonal peaks in frequency, related to temperature in Macrotermes michaelseni and to moisture in sympatric soil nesting Termitidae. Foraging was mostly on woody litter of the dominant canopy trees and mammalian dung. There was considerable overlap in the selection of food items between species but M. michaelseni were seen more frequently on items of woody litter greater than 6 mm in diameter. In Petri-dish trials Microtermes spp. workers were aggressive towards M. michaelseni individuals and in the field they foraged more frequently and effectively when M. michaelseni numbers were experimentally reduced. Macrotermes michaelseni appeared to avoid competition with other fungus-growing species by spatial separation within the habitat and some limited separation in food selection, but intense competition is probably rare as space and food resources may rarely be limiting.

Flood depth has been frequently used to explain the distribution of plant species in seasonally flooded grasslands, but its relation with vegetation production has remained ambiguous. The relationship between flooding and above-ground biomass at the end of the flooding season and during the dry season was studied to assess the impact of reflooding on the Logone floodplain, Cameroon. Above-ground biomass of a combination of all species and of the individual perennial grasses Oryza longistaminata and Echinochloa pyramidalis showed a positive linear relationship with maximum flood depth up to 1 m. The gradient of these relationships became steeper and their fit better during the 2 y following the installation of the flooding, showing the response lag to floodplain rehabilitation. Flood duration only explained the above-ground biomass of the combination of all species and not of the individual species. Above-ground biomass data from other floodplains in the three main African geographic regions showed a similar relationship with maximum flood depth less than 1 m. Dry-season regrowth, important because of its high nutrient quality during forage scarcity, was not directly related to maximum flood depth, possibly because of its dependency on the period of burning and soil moisture. Presented data indicate that a rise of water level of 1 cm corresponds to an increase in above-ground biomass of c. 150 kg DM ha−1.

Secondary forests promote an increased abundance of leaf-cutting ants (LCA) but the consequences on forest dynamics have been poorly addressed. Here we examine seedling assemblage attributes, seed germination and seedling survival across foraging zones of Atta cephalotes colonies inhabiting 15 second-growth patches (25–47 y old) of Atlantic forest. Seeds and seedlings were monitored within foraging zones and control sites over 1 y, including spots around ant nests. Overall, 1862 seedlings from 108 plant species were recorded. Seedling density decreased by 53% in foraging-zone plots (3.31 ± 0.23 seedlings m−2) when compared with control plots (7.02 ± 0.44 seedlings m−2) and a similar decrease was observed for species richness. Ant-induced alterations in the seedling assemblage were further indicated by segregation between foraging-zone and control plots (NMDS), habitat effects on species similarity (ANOSIM), and indicator tree species associated with control plots. While seed germination and seedling survivorship were uncorrelated to either nest distance or age of second-growth stands (with the exception of Tapirira guianensis), defoliation by LCAs was a significant cause of seedling mortality. Our results suggest that LCAs interfere with successional trajectories of Atlantic forest as foraging zones filter seedling establishment, supporting less-dense, impoverished and convergent seedling assemblages.

Fallen tree trunks (‘nurse logs’) are important recruitment sites for trees in temperate forest, however nurse log use is seldom reported in tropical forests. We predicted that logs should be important for the regeneration of small-seeded tropical pioneer species because surface leaf litter and competition with established vegetation reduces the establishment success of these species from soil seed banks. In a survey on Barro Colorado Island, Panama, we found that pioneer seedlings were present on logs in 40 of 95 recent treefall gaps. In gaps where seedlings were present on logs, seedling density was not significantly different from adjacent areas of soil. However, species composition was significantly different; logs were disproportionately colonized by smaller-seeded and wind-dispersed species. In growing-house experiments using 12 species, we found that wood substrate had little effect on seed germination. In contrast, seedling growth was 50% lower on decayed wood than soil. Furthermore, species growth rates on wood were not significantly correlated with growth rates in soil (df = 10, r = 0.48). If establishment on logs eventually leads to recruitment to the forest canopy, then logs may promote the maintenance of diversity by favouring a different group of species from those that recruit in soil.

Upper Amazonian tree communities are famous for their very high alpha-diversity. This paper describes an anomalous forest just 6 km south of the equator in lowland Ecuador that is structurally mature, surrounded by hyperdiverse forest, but strikingly poor in species. To investigate the anomaly, a 1-ha tree inventory and soil analysis were carried out and compared with 15 similar surveys of upland forest in the same region. The anomalous forest contains only 102 tree species ha−1, compared with a regional mean of 239±28 species ha−1. It is structurally indistinguishable from richer forests, and closest in composition to upland forest, but lacks the uplands' typically rich understorey tree community. Three hypotheses for its origin are examined: recovery from anthropogenic disturbance, unique soil conditions and recovery from a large-scale natural catastrophe. The third hypothesis is the best supported. Mineralogical, geological and remote-sensing evidence, and 14C-dating suggest that the forest grows on a vast debris plain left by a catastrophic flooding event roughly 500 y ago. The forest's low diversity today is most likely due to the failure of a full complement of the region's tree species – especially understorey taxa – to recolonize the outwash plain in the time since the disaster.

Petioles are not usually thought of as a habitat for wood-boring insects. The large, woody leaf petioles of Neotropical Cecropia trees, however, have a diverse coleopterous fauna: 36 beetle species in three subfamilies of Cerambycidae and Curculionidae were recorded from Cecropia leafstalks in Costa Rica. A high percentage of the petioles were colonized by beetles in many patches, though fewer were colonized in sun-exposed sites. Community composition was dependent on forest type, petiole moisture and geographical location, but not on the species of Cecropia. Species of Scolytinae were most abundant though species of Zygopinae and Lamiinae were found regularly. The host-specific scolytine genus Scolytodes dominated in most localities, although species of Hypothenemus, Coccotrypes and Xylosandrus morigerus occurred frequently. Sympatric species of Scolytodes clearly used different parts of the petioles. Brood sizes of scolytine beetles were extremely low, ranging from two to ten offspring on average. However, mortality due to parasitoid wasps or predators was low, and since fresh leaves fall close to the previously fallen ones, mortality due to dispersal may also be low. Thus, large beetle populations can exist despite extremely low brood sizes.

Damage to Hawaiian Acacia koa forest by Hurricane Iniki was assessed by comparison with our previous measures of stand structure and leaf area index (LAI) at sites along a precipitation/elevation gradient on western Kauai. Reductions in LAI ranged from 29 to 80% and were correlated with pre-hurricane LAI and canopy height. The canopy damage resulted in a large pulse of litter, ranging from 4 to 19 t ha-1 across our study sites. In the first year post-hurricane, LAI recovery and relative increase in stand basal area were negatively correlated with the fraction of canopy LAI lost. The two major overstorey species, A. koa and Metrosiderous polymorpha, were damaged less than the sub-canopy species, Dodonaea viscosa and Psidium guajava. Although D. viscosa and P. guajava were both severely damaged in the hurricane, the alien species P. guajava had much higher survival than the native D. viscosa, both as adults and as seedlings. However, seedling density of P. guajava was limited by low recruitment. At these sites, there was no drastic change in species composition following hurricane disturbance, and forest structure and productivity had recovered to a great degree within 2 y.

Tropical forests are three-dimensional spaces with species and resources heterogeneously distributed. The vertical stratification of tropical forest biotas has been observed for several organisms and regions, but, surprisingly, the vertical structuring of large areas of important tropical forests, such as Brazil's Atlantic Forest, remains poorly studied. Here, we addressed the use of different Atlantic Forest strata by bats, comparing ensemble composition and relative abundance between the understorey and the canopy. A total of 618 bats belonging to 31 species and four families were recorded, including 11 species of frugivores and seven species of gleaning insectivores, the two trophic guilds predominantly represented in our sampling. Fifteen species were captured exclusively in the canopy, and six exclusively in the understorey, and many of those species were represented by a low number of captures (<5). The bat species composition, richness and relative abundance between canopy and understorey strata varied. Chiroderma villosum was exclusively captured in the canopy, Artibeus lituratus was netted predominantly in the canopy and Carollia perspicillata and Desmodus rotundus were mostly captured in the understorey. Although processes such as resource partitioning between species and ecomorphological constraints may explain the differential use of forest strata, this remains little understood because of the scarcity of data for the Atlantic forest canopies.

Discontinuity between suitable aquatic and terrestrial habitats forces many amphibian species with aquatic larvae to undertake risky breeding migrations through disturbed environments, potentially contributing to population declines by reducing survival of adults and juveniles (Becker et al. 2007). The north-western region of the state of São Paulo, Brazil, is characterized by fragments of mesophytic semideciduous forest and savanna, surrounded by a matrix of pasture, plantations and urban areas with only 4% of the remaining original vegetation of the state (Ribeiro et al. 2009). Currently, 36 anuran species have been recorded in this region, corresponding to almost 15% of the state's species (Araújo et al. 2009). The anuran species of this region are associated with open environments or are widely distributed in the different Brazilian biomes (Duellman 1999). Silva & Rossa-Feres (2007) showed the importance of forest fragments in this region for 12 anuran species that breed in pools located in a pasture matrix.

Larvae of Plagiometriona aff. flavescens carry a structure on their back made of faeces and exuviae, called faecal shield, which may protect larvae against natural enemies. Previous investigations suggested that the nature of such protection was chemical. To test if chemicals found in the faecal shield of Plagiometriona aff. flavescens provided defence for larvae, experiments in the field and in the laboratory (using the ant Camponotus crassus, and chicks Gallus gallus as model predators) were undertaken. Both field and laboratory experiments showed that live larvae with faecal shields, as well as baits treated with faecal shield extracts, were rejected by predators, confirming the chemical nature of this kind of defence.

Because of its position on the northern margin of the tropics (22° 17′N) and the southern coast of a huge continent, Hong Kong has a climate in which both temperature and rainfall are highly seasonal. Although summer temperatures are equatorial, the January mean is only 15.8 °C,and the absolute minimum recorded at sea level is 0 °C (Dudgeon & Corlett 1994). As a result, all aspects of the ecology of Hong Kong show seasonal changes. The most dramatic changes occur in the bird fauna, with the majority of species migratory (Carey et al. 2001). The winter fruiting peak in secondary shrublands and the forest understorey coincides with the arrival of partially frugivorous migrant robins and thrushes (Corlett 1993). However, while resident insectivore-frugivores consume almost entirely fruit during this period (Corlett 1998), all the winter visitors continue to eat insects and some (e.g. Phylloscopus warblers) are entirely insectivorous. The study of insect seasonality reported here formed part of a 30-mo study of the seasonality of a forest bird community in Hong Kong (Kwok & Corlett 1999, 2000). Plant names follow Corlett et al. (2000).

Wood pieces of a heavy hardwood Neobalanocarpus heimii (King) P. S. Ashton and a light hardwood Shorea macroptera Dyer were used in decomposition experiments with termite-exclusion and control trays on the forest floor of the Pasoh Forest Reserve, West Malaysia to determine effects of wood quality on termite-mediated wood decay. Shorea macroptera had a significant loss of C in the presence of termites while Neobalanocarpus heimii showed no significant termite effect. Neobalanocarpus heimii and S. macroptera both accumulated N in the absence of termites, but S. macroptera lost it when termites were present. The C/N ratio decreased with and without termites as decay proceeded in both species. Neobalanocarpus heimii accumulated P, but S. macroptera lost it with and without termites. The C/P ratio decreased in N. heimii, but did not change in S. macroptera. Decomposition was considerably enhanced by termites in S. macroptera, but not in N. heimii, indicating that termite foraging activity was affected by the different wood qualities of the two trees. The qualities responsible for the differences and how different wood qualities affect nutrient cycling in the tropical rain forest ecosystem are discussed.