Thirty-six of the 70 species of bats known from Belize were recorded from the area around Lamanai, Orange Walk County: two in roosts and 34 in about 680 mist net hours that produced 560 captures. Day roosts used by 35 of the species were located using radio-tracking (Sturnira lilium, Platyrrhinus helleri, Centurio senex and Bauerus dubiaquercus) or general searching for roosts (Rhynchonycteris naso, Saccopteryx bilineata, Saccopteryx leptura, Dicli durus albus, Mimon bennettii, Micronycteris schmidtorum, Carollia brevicauda, Carollia perspicillata and Eptesicus furinalis). Data on the day roosts of 23 other species were determined from the literature. Most species reported from Lamanai (19) roosted in hollows, while others used foliage (6), tents (3), sheltered sites (2), crevices (2), open sites (1), and a few species used more than one type of day roost (hollows and crevices (1); hollows and foliage (1); hollows, foliage and tents (1)). The fauna consisted of 13 aerial foragers, 9 gleaners, 11 fruit/leaf eaters, one trawler, one flower-visitor and one blood-feeder. In day roost use and foraging behaviour, the Lamanai fauna did not differ significantly from that of Paracou, French Guiana, but both these locations differed from the bat fauna of Kruger National Park, South Africa, in foraging behaviour.

A recently developed technique in soil ecology is the use of the bait lamina method, for assessing the feeding activity of soil animals in situ. Here the bait lamina method (slightly adapted to tropical conditions) was used for the comparison of four closely situated sites (a primary rain forest, a secondary rain forest and two mixed-species tree plantations) in the Brazilian Amazon (project SHIFT ENV-52). The total feeding activity (portion of empty apertures in a set of laminae) and the vertical distribution of the feeding activity were evaluated for differences between the sites. The feeding activities in the primary and secondary forest were at the same level and significantly lower than in the two plantations. Feeding activity in subplots where surface litter has been experimentally removed was significantly lower than in the controls with the litter layer intact, at all four sites. The abundance of soil macrofauna or Enchytraeidae was not correlated with the results of the bait lamina tests, while the abundance of mesofauna (probably mainly Oribatida) was consistent with the pattern of feeding activity. The feeding activities as determined with bait laminae did not correlate with the decomposition activities determined with litterbags. Due to the easy applicability in combination with its feasibility for statistical evaluation and its consistent responses to site differences in experimental treatments we consider the bait lamina method to be a promising approach for the biological assessment of tropical soils.

An understanding of the abundance of organisms is central to understanding ecology, but many population density estimates are unrepresentative because they were obtained from study areas chosen for the high abundance of the target species. For example, from a pool of 1072 lizard density estimates that we compiled from the literature, we sampled 303 estimates and scored each for its assessment of the degree to which the study site was representative. Less than half (45%) indicated that the study area was chosen to be representative of the population or habitat. An additional 15% reported that individual plots or transects were chosen randomly, but this often indicated only that the sample points were located randomly within a study area chosen for its high abundance of the target species. The remainder of the studies either gave no information or specified that the study area was chosen because the focal species was locally abundant.

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.

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.

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.

Although fire is occurring at greater frequencies and spatial scales in the moist tropics, few studies have examined the ecological impacts of fire in tropical montane cloud forest (TMCF). This study, conducted in the Chimalapas region of Oaxaca, Mexico, documents changes in live tree biomass, live fine-root biomass, and fallen and standing dead wood 4 y following deep ground fires occurring in TMCF during the 1997–98 El Niño Southern Oscillation event. Forests growing on two different substrates (metamorphic and sedimentary) and having three different statures (mean canopy heights: 20–30 m, 15–20 m and 4–6 m) were assessed within six paired plots established on adjacent burned and unburned forest sites. Total live tree biomass was 82% and 88% lower for burned TMCF growing on metamorphic and sedimentary substrates, respectively, compared with unburned TMCF. Nearly 100% of the living biomass was killed in elfin TMCF located on exposed sedimentary limestone at the highest elevations. Live fine-root biomass in the upper organic soil horizon of burned TMCF sites was 49% lower on metamorphic substrates and 77% lower on sedimentary substrates compared with unburned sites. The amount of total dead wood was 3- to 14-fold greater in burned forests compared with unburned forests. These results suggest that first-time fires in relatively undisturbed TMCF can cause dramatic changes in live above- and below-ground biomass at levels greatly exceeding values reported for most lowland tropical rain forests. These patterns may be attributed to the slower decomposition rates and thick organic soils typical of TMCF, combined with the relatively fast drainage associated with steep topography and, in some locations, sedimentary limestone-derived substrates.

The role of regeneration strategies in structuring tropical tree communities has been a recent focus of attention of tropical ecologists. Canopy discontinuities created by tree-falls are considered to be critical to many rain forest trees for establishing and completing their life cycles. It was investigated whether it is advantageous for two common large-seeded and shadetolerant Amazonian tree species, the palm Astrocaryum murumuru and the legume, Dipteryx micrantha, to have their seeds dispersed to gaps. The dispersal process was simulated by placing experimental seeds and seedlings in gaps and in the shaded understorey, and then following their performance. Seeds and seedlings from the two species were used. The Cox proportional hazard model was used to estimate the survival functions and compare survivorship curves. Survival of Astrocaryum seeds, and of Dipteryx seeds and seedlings, was higher in two gap zones (crown and bole) than in the shaded understorey (both near and far away from a conspecific adult). A higher proportion of seedlings of both plant species survived within gaps than in the shaded understorey over an 18-wk period. One year after the seedlings had been transplanted into gaps these patterns still held. Naturally occurring Astrocaryum seeds survived better beneath conspecific adult trees located within 30 m of gaps than beneath trees located 100 m from gaps. Variation in gap size was significant for Dipteryx seeds, but not for Dipteryx seedlings and Astrocaryum seeds and seedlings. Dipteryx seeds survived longer in smaller than in larger gaps. By colonizing tree-fall gaps, these two species improved their chances of completing their life cycles.

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.

Leafing, flowering and fruiting of the 24 most representative species of trees and shrubs in Sudanian savannas and fallows near Bondoukuy (Burkina Faso) were studied for 2 y (May 1992 to June 1994). The period of defoliation was generally brief, and leaf flushing, flowering and fruiting occurred mostly in the dry season. The phenological behaviour varied nonetheless across species and individuals. A classification taking into account synchrony/asynchrony and duration in foliation, flowering, fruit ripening and seed dispersal phases allowed comparison of species' phenological plasticity. Species were distributed along a scale of increasing plasticity, from trees to shrubs. Along this scale, species of the Leguminosae appeared to be separated from those of the Combretaceae, the latter being generally considered as characterising fallow farming systems. These results provide new evidence about the effect of phylogenetic constraints on the phenological behaviour of the woody species of the Sudanian savannas.

RÉSUMÉ. La feuillaison, la floraison et la fructification des 24 espèces d'arbres et d'arbustes les plus représentatives des jachères et savanes soudaniennes de la région de Bondoukuy (Burkina Faso), ont été étudiées pendant 2 ans (mai 1992 à juin 1994). La défeuillaison est généralement brève et l'émergence des feuilles, la floraison et la fructification se produisent principalement pendant la saison sèche. Les comportements phénologiques varient cependant entre les individus et entre les espèces. Une classification prenant en compte le degré de synchronisme ainsi que la durée de la feuillaison, de la floraison, de la maturation des fruits et de la dispersion des graines a permis de comparer la plasticité phénologique des espèces. Celles-ci sont distribuées selon un gradient de plasticité croissante des arbres aux arbustes. Sur ce gradient les Légumineuses se dissocient des Combrétacées, espèces qui sont par ailleurs généralement considérées comme caractéristiques des jachères. Ces résultats sont une nouvelle illustration de l'effet des contraintes phylogénétiques sur le comportement phénologique des espèces ligneuses des savanes soudaniennes.

Plants often modify microsite conditions important for seedling establishment. In tropical moist forest, advance regeneration in the form of shade-suppressed seedlings is a major component of regrowth in new gaps. Tree seedlings may be filtered by the composition and structure of the forest understorey. In a lowland forest in Central Panama, we examined light availability, litter accumulation and the seedling community (abundance, diversity and composition) under and away from the canopies of a common subcanopy, clonal palm, Oenocarpus mapora, and tested whether seedling abundance varies as a function of changes in understorey light conditions and leaf litter depth. We found evidence that leaf litter was five times deeper and light availability 27% lower under O. mapora canopy than where it was absent. The probability of finding a seedling in plots under O. mapora canopies was 33% lower than in plots without the palm. Plots under O. mapora canopies also had 49% fewer species of seedlings and those seedlings came from significantly larger seeds than seedlings in plots not under the palm. Overall, seedling density was positively correlated with light availability and negatively correlated with leaf litter depth. A transplant experiment confirmed that for at least one large-seeded species of dicot, seedlings are negatively affected by the reduction in light availability and increase in leaf litter. Under O. mapora, seedlings of Gustavia superba (Lecythidaceae) had lower survivorship and biomass accumulation than away from the palm. Thus, site conditions produced by large, clonal, multi-layered palms such as O. mapora may reduce establishment of small-seeded and shade-intolerant species, potentially affecting species composition in the understorey seedling pool.

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.

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.

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.

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.

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.

We mapped the occurrence of canopy gaps periodically between 1978 and 1990 in a 1.5 ha study plot within a 70-year-old (in 1978) Neotropical forest on Barro Colorado Island (BCI), Republic of Panama. The total area of the forest under canopy gaps in the plot averaged 4.3% (3.1% to 5.7%, 95% CI). There was high year-to-year variability in the rate of new gap formation. On the basis of repeated observations for four yearly intervals, the annual rate of new gap formation ranged from 0.45% y−1 to 6.5% y−1. Most gaps were small. The mean size of individual gaps originally was 79 m2 (range: 8-604 m2). However, large gaps (≥150 m2) occurred more frequently than expected for a secondary forest on BCI. Gaps closed rapidly the first year after formation but the rate of closure slowed thereafter. Despite the absence of any obvious environmental gradients, gaps were spatially clustered. Even in this relatively small plot, there seemed to be distinct gap-prone and gap-free areas.

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.

Diurnal and nocturnal censuses were conducted on animal visitors at a single strangler Ficus aff. cotinifolia (H.B.K.) tree during the entire period of ripe fruit availability. Fruit fall to the ground was measured with fruit traps, and chemical analyses were conducted on the figs. Fourteen species of birds, four species of nonvolant mammals and two species of bats consumed the figs. Of the total number of ripe figs accounted for during the sampling period (N= 1.9 X 105), 42% fell to the ground, 45% were removed by mammals and 13% by birds. Frugivores such as the howling monkey Alouatta palliata, the cacomistle Bassariscus sumichrasti, the keel-billed toucan Ramphastos sulphuratus and fruit-eating bats removed the largest amounts of figs from the tree and deposited seeds of 13 plant species other than figs below the tree crown.