Man-made grasslands dominated by Imperata cylindrica (L.) Beauv. in forested areas of lowland Nepal are commonly cut and/or burned annually. Changes in grass forage quality following different treatments of cutting and burning and axis deer (Axis axis) response to such habitat manipulations were investigated. Samples of matured grass were collected in December 1990, February and April 1991 from three experimental sites: cut, burned, cut-and-burned. Four locations on cut-and-burned grassland were repeatedly sampled at 12-d intervals from January to April 1992. Numbers of axis deer were recorded during the dry season of 1991/1992 on grassland plots receiving the following treatments: cut, cut-and-burned, and uncut/unburned (controls). Based on grass quality differences between December and February and between December and April, cut-and-burned treatments gave the greater increase in forage quality. N was significantly higher on cut-and-burned plots than on cut plots both in February and in April, while Na, K and P was significantly higher in February. On plots cut-and-burned in January, Ca concentrations were relatively low while the P content fell below required levels for domestic stock towards the end of the dry season in April. Na concentrations were below the minimum required levels for both domestic and wild ruminants during the whole period. When an entire grassland was cut, deer density increased gradually. When the same area was subsequently burned, the daily deer density increased much more rapidly. Axis deer preferred burned plots compared to plots neither cut nor burned and to cut plots. Plots burned in late February had higher densities of axis deer than plots burned 1.5 mo earlier. When nearby recently burned plots were available, deer density was reduced on plots burned earlier.

The number of elephants living in the forests of Gabon was estimated by a stratified dung survey. The forest zone was stratified according to the distribution of the human population. The density of dung-piles was estimated for each stratum by the line-transect method. The total number of dung-piles in the forests of Gabon was estimated to be 52.43 × 106 ± 13.25 × 106. This gave an elephant estimate of 61,800 ±20,200. This survey shows Gabon to have one of the largest elephant populations on the continent.

This study describes changes in the numbers of plant species fruiting during six years in I ha of Amazonian savanna on the right bank of the Tapajós River, Brazil. The work was based on fleshy fruits from tree and shrub-layer species eaten by birds. The area was burned in the first two years, protected during the following two years and burned again in the last two years. The number of tree species fruiting did not differ significantly between years with and without fire. The number of shrub-layer species fruiting was markedly reduced in years with fire, but the responses varied between species. Data on changes in shrub cover after two consecutive years of fire indicate that species also respond differently in terms of biomass lost due to fires. The two most abundant genera of shrubs, Miconia and Myrcia, had their cover reduced by up to 95% and 72% respectively. The area made available by the loss of shrubs was occupied mainly by the grass Paspalum carinatum. The fires and the decrease in the availability of fruits occurred during the season in which most species of birds breed. An interval of less than three years between fires is insufficient for shrub-layer species to recover.

A prediction of the hypothesis that niche processes control plant species distributions across edaphic gradients is that pairwise comparisons of related species on contrasting soils should show consistent patterns of trait divergence. This hypothesis was tested in lowland Bornean rain forest by combining measurements of leaf traits, soil nutrients and the distribution of tree species in the Dipterocarpaceae across a nutrient gradient. Nine species were studied, comprising four related pairs in Shorea (phylogenetic independent contrasts; PICs) and one habitat generalist (Dipterocarpus sublamellatus). Lamina area, specific leaf area (SLA), leaf nitrogen (N) and phosphorus (P) were measured for ∼10 saplings of each species; habitat associations were defined as a continuous function of soil nutrients and categorically in relation to substrate. Species distributions and traits varied significantly with soil nutrients. When all species were pooled, SLA and leaf P increased significantly with species' distribution across the nutrient gradient; leaf N showed the same trend. Trait shifts with habitat were stronger and more pervasive when habitat was defined categorically – in all four PICs, rich-soil specialists had larger leaves, higher SLA, leaf N and P, and lower N:P ratios. Trait shifts with habitat at least partly reflect intrinsic differences between species. Within Shorea, variation in lamina area and N:P ratio were more strongly related to phylogeny than habitat, whereas the reverse held for SLA and leaf P. Phylogeny also influenced the extent of trait divergence between related species on different soils, and patterns of trait correlation within lineages. Results support the hypothesis that niche processes influence the distribution of species and traits in lowland tropical tree communities, and highlight the value of phylogenetic information for increasing the power of comparative studies.

Tropical montane forests (TMF) are associated with a widely observed suite of characteristics encompassing forest structure, plant traits and biogeochemistry. With respect to nutrient relations, montane forests are characterized by slow decomposition of organic matter, high investment in below-ground biomass and poor litter quality, relative to tropical lowland forests. However, within TMF there is considerable variation in substrate age, parent material, disturbance and species composition. Here we emphasize that many TMFs are likely to be co-limited by multiple nutrients, and that feedback among soil properties, species traits, microbial communities and environmental conditions drive forest productivity and soil carbon storage. To date, studies of the biogeochemistry of montane forests have been restricted to a few, mostly neotropical, sites and focused mainly on trees while ignoring mycorrhizas, epiphytes and microbial community structure. Incorporating the geographic, environmental and biotic variability in TMF will lead to a greater recognition of plant–soil feedbacks that are critical to understanding constraints on productivity, both under present conditions and under future climate, nitrogen-deposition and land-use scenarios.

Quantitative analyses of the factors driving the distribution of bryophytes in the phyllosphere of tropical rain forests are rare. In this study we sampled epiphyllous bryophytes on two leaves of each of 57 individuals belonging to four phorophyte species (Asplundia pittieri, Carludovica drudei, Costus laevis and Dieffenbachia concinna) at three adjacent, but microclimatically varied sites in the Esquinas forest, Costa Rica. Microclimatic parameters and phorophyte identities were correlated to differences in cover, diversity and species composition of bryophyte assemblages by means of Kruskal–Wallis tests, non-metric multidimensional scaling and indicator species analysis. High relative humidity and in particular daily fluctuations in relative humidity proved to be the most important factors for epiphyll distribution suggesting severe constraints of epiphyll colonisation by pronounced humidity fluctuations. Differences in air temperature and light availability as well as phorophyte identity were only weakly correlated with bryophyte cover and diversity. However, species composition of epiphyllous assemblages was related to all microclimatic variables as well as to phorophyte identity. The strong response of epiphyllous bryophytes to even subtle microclimatic variations suggests that undisturbed forest canopies and their control on microclimate may be essential for the development of epiphyll communities.

This study investigates the movements and home range of the agouti (Dasyprocta punctata) on Barro Colorado Island, Panama. We captured and tracked 12 agoutis from January to December 2003. Home-range size (95% kernel) ranged from 1.56–2.45 ha (n = 6) for males and 1.34–1.97 ha (n = 5) for females. Agouti ranges overlapped and we estimated a density of approximately 100 agoutis km−2. We compared agouti movement with the locations of refuges and food trees, and the results suggest that the agoutis are central-place foragers. Agoutis moved an average of 850 m d−1 covering approximately 35% of their range daily. These movement data help us understand the potential impacts of agoutis as seed dispersers, predicting that D. punctata will encounter and hoard fallen fruit within 10–200 m (i.e. radius of home range) of its source, and move seeds towards refuges such as ground holes and dense vegetation around recent tree falls.

Because anuran species are highly dependent on environmental variables, we hypothesized that anuran species richness and the number of reproductive modes from different Brazilian localities vary according to climatic and altitudinal variables. Published data were compiled from 36 Brazilian localities and climatic and altitudinal data were extracted from an available database. A partial redundancy analysis (pRDA) showed that 23.5% of the data set's variation was explained by climatic and altitudinal data, while the remaining 76.5% remained unexplained. This analysis suggests that other factors not analysed herein may also be important for predicting anuran species richness and the number of reproductive modes in Brazil. Altitude and total annual rainfall were positively correlated with anuran species richness and the number of reproductive modes, and total annual rainfall was strongly associated with these two biotic variables in the triplot of pRDA. The positive association of total annual rainfall and the negative association of the concentration of annual rainfall were already expected based on physiological and reproductive requirements of anurans. On the other hand, temperature was not associated with richness or the number of reproductive modes.

In 14 forest plots (36 m2) all terrestrial plant species were recorded before slashing and burning of the vegetation. During subsequent cultivation with rainfed rice all resprouting plants were registered in permanent plots (72 m2). The fields studied (one per forest) covered all combinations of forest type and soil usually cultivated on local farms. Forest plots (total 409 species) and field plots (358 species) had 226 species in common. Most resprouting plants were woody. Though nine forests in the sample were secondary, 70% of resprouting plants belonged to primary forest species and with three exceptions, these species did not regenerate by seed.

Experiments in one field inlcuded: different intensities of initial burning, weeding (none, once, twice) and length of the rice cultivation period (1, 2, 3 y). Resprouting plants were monitored in permanent plots (108 m2) during 3 y of cultivation and 2 y of fallow. More plants resprouted after a mild initial burning (5.8 plants m−2) than after a burn of normal intensity (1.4 plants m−2). Weeding and prolonged cultivation strongly reduced species diversity but plant densities were less affected because some climbers and trees were apparently stimulated and expanded.

Fields abandoned after one rice harvest had, within six months, a closed forest canopy of pioneer trees emerging from the pre-existing seed bank and from the growth of resprouting trees. Prolonged cultivation (3 y) destroyed the pre-existing seed bank but affected sprouting plants less, these being the only component in the vegetation able to shade out weeds and forbs such as Chromolaena odorata.

In the first 3 mo of 1998, an aseasonal tropical rain forest at Lambir Hills National Park on the north-west coast of Borneo suffered an unusually severe drought. Extreme climatic events such as this one are expected to influence tree population structure and community dynamics through differential effects on growth and mortality. The demographics of seedlings of seven shade-tolerant tree species, including two dipterocarps, during this severe drought were contrasted with baseline demographic data from two earlier census intervals, one of which included a slight drought, and one of which included no drought. Hemispherical photographs were used to document an opening of the canopy that resulted from the dieback and mortality of large trees during the severe 1998 drought. Seedlings that experienced an increase in canopy openness were less likely to die than other seedlings. Rates of mortality and height loss were significantly increased in association with drought. The overall mortality rates during the severe drought and slight drought census intervals were 8.2% y-1 and 7.3% y-1 respectively, compared with 4.9% y-1 for the non-drought census interval. The incidence of height loss during the severe drought census interval was 27.5%, compared with rates of 11.7% and 20.1% for earlier census intervals. Dipterocarp species were less affected than some non-dipterocarp species, and the smallest seedlings suffered the greatest impact. If droughts in this region continue to increase in intensity and severity, they may ultimately cause a change in the species population densities and stand structure of the understorey seedling community of this rain forest.

Plots of 1.25 and 11.25 ha were enumerated for trees and lianes ≥10 cm and trees ≥70 cm dbh respectively along a line transect in the Lopé Reserve, Gabon. In the small plot 511 trees and lianes of 116 species were found, and 175 trees of 48 species were present in the large plot. The plots were then subject to commercial mechanised logging and the enumerations were repeated once logging had been completed. The extraction rate was two trees ha−1 and in the large plot a total of 31 (17.7%) trees representing 20.6% of the total original basal area died. Incidental damage in the small plot resulted in the loss of 10.8% of trees and lianes present, and 12.9% of the original basal area. Canopy cover was reduced by 10%. Damage levels were low compared with figures from most other tropical regions. The relevance of these figures to forest management in Gabon are discussed.

Effects of extreme livestock pressure on the abundance and distribution of a drought-deciduous shrub Sericocomopsis pallida, and effects of the shrub canopy on microclimate, soil fertility and grass production, were studied in savanna grasslands of southern Kenya. Canopy volume declined with increasing herbivore pressure, but shrub density was not systematically affected, suggesting strong resilience against destruction by herbivores. However, shrubs became more aggregated with increasing herbivory, suggesting that clumps of individuals are more resilient to destruction than are isolated individuals. Grass production was three times greater under the canopy of S. pallida than in the open. Comparisons of physical-chemical properties among soils derived from four microsites revealed far higher nutrient levels in sub-canopy soil than in soil derived from open ground between canopies, and radically different properties compared to soil heavily enriched with livestock dung and urine. Higher nutrient levels beneath the canopy most likely resulted from Utter decomposition.

A pot experiment, designed to simulate shading and soil conditions in the field, showed that grass growth promotion was largely due to a substantial increase in soil fertility beneath the canopy of S. pallida, comparable to grass productivity in soil enriched with livestock excreta. However, this increase in sub-canopy grass production did not significantly increase regional grass layer production.

Most trees in the eucalypt savannas of Australia have hollow cores, or pipes, caused by termite activity, yet little is known about their effect on tree growth or survival. Five hundred and forty-one trees with known growth and survival histories were cored to determine pipe diameters in wooded savanna of Kakadu National Park, north Australia. Generalized linear modelling and multi-model inference was used to analyse frequency and degree of piping relative to initial tree diameter at breast height (dbh), eco-taxonomic group or species of eucalypt. Growth (dbh increment) and survival (4 y) were analysed relative to initial tree size, pipe ratio (pipe diameter:dbh) and eco-taxonomic group. The frequency of piping was strongly dependent on dbh, increasing with size of tree, and was highest in eucalypts. Growth and survival of eucalypts increased with tree diameter and decreased with pipe ratio. For example, from modelled data, 10-cm-diameter trees without pipes grew 0.14 cm y−1 with 85% survival vs. 10-cm trees with pipe ratios of 0.60 which had near-zero growth and only 46% survival. Comparing 40-cm-diameter trees without pipes to those having pipe ratios of 0.80, growth was 0.22 vs. 0.05 cm y−1, with little difference in survival, 97–99%, respectively. Contrary to the suggestion that tree hollows are an adaptive trait whereby trees benefit by the release of nutrients, in the north Australian eucalypt savannas the net effect of termite piping on individual tree growth and survival was negative.

The effect of natural canopy gaps on the performance of naturally occurring tree seedling populations was studied in a tropical rain forest in French Guiana. This was done at two levels of scale. Firstly, on a 20 m × 250 m forest transect intersecting four canopy gaps, it was investigated how patterns of recruitment, growth and survival of seedlings of Cecropia obtusa, Dicorynia guianensis and Pourouma bicolor differed between canopy gaps and closed forest. Secondly, for one large natural canopy gap, performance of seedling cohorts established before (‘pre-gap’ cohorts) and after (‘post-gap’ cohorts) gap formation was studied in relation to environmental heterogeneity. The direct site factor (DSF) was used as an indicator of light availability in the gap zone. Cecropia specialised in large gaps, and also in specific sites within the large gap: seedling performance was increased by light, and by dead wood. Pourouma mainly germinated under closed forest conditions, where it can survive for a long period until a canopy gap is formed nearby. Pourouma seedlings adjusted well to the new gap environment but they did not specialise in specific places within the gap. Seedling location of Pourouma seedlings was mainly determined by accidental positioning before gap formation. Dicorynia was able to germinate both in gaps and under closed forest conditions. Although the number of gaps studied in this study was low, the results show that seedling establishment, early growth and survival of the three tree species were affected by canopy gaps and by the environmental heterogeneity within a large gap.

I provide evidence that migrating birds concentrate in tropical second-growth woodlands due, in part, to a greater abundance of small fruits. Migrant birds markedly increased in abundance during spring migration in late March in a young (approximately 25 years old) second-growth woodland in Panama. Migrant abundance and diversity was greater at mist-net level on the second-growth site than in nearby old forest. Diversity of canopy migrants also was greater in the young woodland than in an old second-growth forest. Thus, many migrant species appear to select young second-growth during spring migration in central Panama. Degree of frugivory by many migrant species was greater during migration than earlier in the dry season. Most migrants selecting the second-growth site were highly frugivorous and migrants accounted for most of the visits to common fruit species, but use of fruit trees appeared to be influenced by fruit size relative to gape width. Most migrants have mouths that are better suited to eating the small fruits predominating in young forest than the larger fruits characteristic of old forest. Abundances of bird-dispersed fruit plants and, particularly, those fruit species known to be eaten by migrants were greater in young than in old forest. The high food demands of migrating birds added to the high degree of frugivory of most migrants selecting second-growth forest suggests that the abundance of small fruits in second-growth may be a strong cause for habitat selection during migration.

Effects of the elephant gut and elephant dung on seed germination and early seedling establishment/growth were investigated in Banyang-Mbo Wildlife Sanctuary using undestroyed seeds of 14 plant species sorted from fresh elephant dung between 1 June 1994 and 31 May 1995 and similar seeds extracted from fresh ripe fruits fallen on the forest floor within the same period both sown in fresh elephant dung and forest soil. Parameters measured were final germination success, germination time and seedling growth rate. Results indicated that two species, Panda oleosa and Poga oleosa, did not germinate at all after 365 d irrespective of their sources and media of planting. Germination success observed in ingested seeds was significantly different from that observed in seeds from fresh fruits. Germination success observed in elephant dung was not significantly different from that in forest soil. Mean germination time varied widely between species and treatments but was generally shorter in seeds that passed through the elephant gut than those collected from fresh ripe fruits and these differences in mean germination time were significant in 92% of the species that germinated. Growth rates of seedlings from ingested seeds were higher than those from fresh ripe fruits especially in elephant dung. Growth medium was highly significant to growth in 10 of 12 species (83%) and source was important only to two species (16%) while their combined interacting effects were significant to three of the 12 species (25%). It is concluded that ingestion of seeds by the elephant is important in the germination of some rain-forest species and the elephant dung that contains the seeds dispersed is very important in the rapid growth of the seedlings. On the basis of germination success plant species that are absolutely or exclusively dependent on elephants for dispersal/germination are absent in Banyang-Mbo Wildlife Sanctuary, while Omphalocarpum elatum and Strychnos aculeata would be on the basis of fruit morphology.

The last population of giraffes in west Africa lives in Niger in an unprotected Sahelian region inhabited by farmers and herders. The spatial behaviour of each individual of the population (n = 63) was studied by direct observation during 15 mo. Two-thirds of the population were resident in the tiger bush in the rainy season and in the nearby area of Harikanassou, a sandy agricultural region, in the dry season. Rainy season and dry season home ranges were mutually exclusive and individual home ranges were overlapping when considering one season (rainy season: 84%; dry season: 67%). The mean size of the seasonal home ranges of these resident giraffes during the dry season (90.7 km2) was twice the mean size during the rainy season (46.6 km2). A third of the population moved 80 to 200 km in three directions, and two giraffes from an isolated group from Mali moved 300 km along the Niger River. Long distance movements of such length have never been reported before, and several explanations are proposed: previous distribution, social transmission, hydrographic network and food availability, poaching events. The giraffes in Niger do not avoid rural communities; indeed, they live in densely populated regions. Furthermore, their movements, synchronized with human activities in these regions, are representative of life conditions in the Sahel.