The dynamics of tropical forest woody plants was studied at the Nouragues Field Station, central French Guiana. Stem density, basal area, above-ground biomass and above-ground net primary productivity, including the contribution of litterfall, were estimated from two large permanent census plots of 12 and 10 ha, established on contrasting soil types, and censused twice, first in 1992–1994, then again in 2000–2002. Mean stem density was 512 stems ha−1 and basal area, 30 m2 ha−1. Stem mortality rate ranged between 1.51% and 2.06% y−1. In both plots, stem density decreased over the study period. Using a correlation between wood density and wood hardness directly measured by a Pilodyn wood tester, we found that the mean wood density was 0.63 g cm−3, 12% smaller than the mean of wood density estimated from the literature values for the species occurring in our plot. Above-ground biomass ranged from 356 to 398 Mg ha−1 (oven-dry mass), and it increased over the census period. Leaf biomass was 6.47 Mg ha−1. Our total estimate of aboveground net primary productivity was 8.81 MgC ha−1 y−1 (in carbon units), not accounting for loss to herbivory, branchfalls, or biogenic volatile organic compounds, which may altogether account for an additional 1 MgC ha−1 y−1. Coarse wood productivity (stem growth plus recruitment) contributed to 4.16 MgC ha−1 y−1. Litterfall contributed to 4.65 MgC ha−1 y−1 with 3.16 MgC ha−1 y−1 due to leaves, 1.10 MgC ha−1 y−1 to twigs, and 0.39 MgC ha−1 y−1 to fruits and flowers. The increase in above-ground biomass for both trees and lianas is consistent with the hypothesis of a shift in the functioning of Amazonian rain forests driven by environmental changes, although alternative hypotheses such as a recovery from past disturbances cannot be ruled out at our site, as suggested by the observed decrease in stem density.

We examine the density- and distance-dependent seedling survival of Philenoptera sutherlandii, a common pod-bearing and dehiscent legume (Fabaceae) in Ongoye Forest, South Africa. Short-range ballistic dispersal causes seed to fall beneath the parent tree, where density- or distance-dependent mortality effects are expected to be concentrated. One hundred and eighty marked seedlings were monitored in a 0.5-ha plot containing 30 adults. Our survival data do not support the escape hypothesis. Predation levels declined with increasing seedling density (positive density-dependent survival), but seedling survival after 15 mo was not distance-dependent. Nevertheless, a unimodal (hump-shaped) recruitment curve, typically associated with decreasing seedling density and increasing seedling survival with distance, was observed. In the context of ballistic dispersal, this recruitment curve may indicate a hump-shaped dispersal kernel with predator satiation at high seedling densities near a parent tree. This recruitment curve likely arises because generalized insect seedling predators while attracted to the adult trees also tend to forage farther away. Short dispersal distances, in turn generate the high densities needed to satiate seed and seedling predators. Predator satiation results in long-term survival rates in P. sutherlandii similar to more widely dispersed and less common tree species.

An on-going controversy in community ecology involves the debate about the many factors that affect the assembly and composition of a given species assemblage. Theory suggests that community composition is influenced by environmental gradients or biotic processes. This study examines patterns of community composition in two tropical tree frog assemblages of primary and exploited lowland rain-forest sites in the Guiana Shield area of central Guyana, South America and the Upper Guinean rain-forest block of south-western Côte d'Ivoire, West Africa. We tested community composition and species abundance data of two adult tree frog communities collected on 21 standardized transects during a period of 5 y for evidence of spatial correlation in community composition. We applied simple and partial Mantel tests to separate the effects of environmental variables, spatial distance and spatial autocorrelation on community composition. Whenever environmental effects were accounted for, we found significant positive spatial correlation of community composition. All assemblages appeared to be spatially structured, i.e. sites in close proximity had similar species assemblages. However, spatially structured environmental variation (autocorrelation) did not account for the spatial structure of species incidence. Environmental factors did not prove to be significant predictors of species incidence in any of the assemblages analysed, even if we controlled for spatial effects. Observed correlation patterns of species composition were consistent within respective realms and disturbance regimes. Moreover, general correlation patterns were consistent between geographic regions. These results are in contrast to previously published results from a study on leaf-litter anurans and indicate that group-specific differences must not be neglected when analysing patterns of species composition in anurans as they may drastically alter the outcome of the analysis.

Primates are among the major groups of frugivores in the tropics, but little is known about their role in natural regeneration of African savanna ecosystems. In the savanna-forest mosaic of north-eastern Ivory Coast the olive baboon (Papio anubis Lesson) harvests fruit from at least 79 plant species. Over a 24-mo study period, 396 faecal samples from 10 groups of baboons were analysed in terms of quantitative and qualitative aspects of seed handling and dispersal (excluding grasses and sedges). Seventy-three per cent of seeds in faecal samples were undamaged. Intact seeds were from 65 species. On average, defecations contained intact seeds from 2.0 species (range = 0–10). Seed size varied between 1 and 27 mm, and 77% of the species had medium-sized to large seeds. No linear correlation between mean seed size and seed damage was found. Eighteen out of 19 species tested were viable after ingestion, but effects of gut passage upon germination varied widely. The baboon population in the study area (145 km2) dispersed an estimated 1483 intact seeds d−1 km−2 (129 seeds > 2 mm in size). The results suggest that the olive baboon is an important seed disperser in the savanna-forest ecosystem of West Africa.

Although the floral traits of Parkia conform to the bat-pollination syndrome, many visitors other than bats have been observed at their flowers. Some chiropterophilous plants are also pollinated by other animals; the syndrome is therefore best regarded as a hypothesis for which field observations and pollination experiments are required. The present study aimed, for the first time, to determine the breeding system of the economically important canopy trees, Parkia speciosa and P. timoriana, and to identify their pollinators. Pollination experiments carried out in Trang and Songkhla Provinces, in 28 trees of P. speciosa and four P. timoriana indicated that they are self incompatible. Open pollination resulted in the highest fruit set (average 60–67% of inflorescences per tree) although this was not significantly different from hand-crossed pollination (48–60%). Insect pollination resulted in fruit set in only 12% of P. speciosa inflorescences. Fruit bats, mainly Eonycteris spelaea, visit flowering plants continuously from dusk till after midnight. Nocturnal and diurnal insects (moths and stingless bees respectively) visit capitula, mostly at the nectar zone. Nectarivorous bats are the most effective pollinator for P. speciosa and P. timoriana. The fact that populations of E. spelaea appear to be declining throughout their distribution is therefore a matter of increasing concern.

We used long-term population data for the ruddy-capped nightingale thrush (Catharus frantzii Cabanis), to examine the influence of forest conditions on annual productivity, survival and growth rate (λ) in a montane forest reserve of Chiapas, southern Mexico, from 1995 to 2003. Productivity was higher in primary, mature forest than in secondary, young forest. More adults were captured in primary forest (n = 132) than in secondary forest (n = 64). Adult survival (φ = 0.79) and encounter rate (ρ = 0.36) did not vary across habitats. Males and females had similar survival between primary and secondary forests (φ = 0.80 vs. 0.83, and 0.77 vs. 0.79, respectively). Juvenile survival (φ = 0.67) was only 12% lower than for adults. Overall, the population of C. frantzii appeared to be declining at 3% y−1 (λ = 0.97, SE = 0.09, 95% CI = 0.88–1.03). Productivity and survival correlated positively with λ across years within habitats, although survival was the primary, significant demographic parameter determining λ. Although habitat alteration may have reduced the carrying capacity and productivity in secondary forest, there was no apparent negative effect on population persistence in this habitat. Thus, secondary forests represent habitats that may facilitate the long-term persistence of C. frantzii populations.

Spatial and temporal variation in seedling dynamics was assessed using records of community-wide seedling demography collected with identical monitoring methods at four tropical lowland forests in Panama, Malaysia, Ecuador and French Guiana for periods of between 3 and 10 y. At each site, the fates of between 8617 and 391 777 seedlings were followed through annual censuses of the 370–1008 1-m2 seedling plots. Within-site spatial and inter-annual variation in density, recruitment, growth and mortality was compared with among-site variability using Bayesian hierarchical modelling to determine the generality of each site's patterns and potential for meaningful comparisons among sites. The Malaysian forest, which experiences community-wide masting, was the most variable in both seedling density and recruitment. However, density varied year-to-year at all sites (CVamong years at site = 8–43%), driven largely by high variability in recruitment rates (CV = 40–117%). At all sites, recruitment was more variable than mortality (CV = 5–64%) or growth (CV = 12–51%). Increases in mortality rates lagged 1 y behind large recruitment events. Within-site spatial variation and inter-annual differences were greater than differences among site averages in all rates, emphasizing the value of long-term comparative studies when generalizing how spatial and temporal variation drive patterns of recruitment in tropical forests.

Although plant species that attract multiple species of pollinators predominate in tropical plant communities, pollination specialists appear to be at a greater advantage in tropical ecosystems in which pollinators are numerous and many plants flower synchronously. The present study determined the breeding system and legitimate pollinators of Oroxylum indicum Vent. in Songkhla and Patthalung Provinces, Thailand. Oroxylum indicum exhibits steady-state flowering, with one or two flowers per inflorescence opening each night. Flowers open in the evening and drop off shortly after midnight, while its bilabiate stigma is highly sensitive, and quickly close upon being touched. Oroxylum indicum is self-incompatible. Hand-cross pollination and open pollination yielded the highest pollination success (47.7% and 31.2% respectively, n = 7 trees). About 900 pollen grains are needed for initiating fruit set. It is confirmed that a fruit bat, Eonycteris spelaea, is the legitimate pollinator. Bats are responsible for all pollen load and the pollen load from only one visit is generally sufficient to initiate fruit set. Although Eonycteris spelaea is effective, it is an inefficient pollinator. Compared with plant species pollinated by multiple animal species, the likelihood of pollination failure resulting from the decline in populations of Eonycteris spelaea will be much more intense in Oroxylum indicum.

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.

Secondary dispersal is an important stage in the life cycle of tree species, determining the fate of a high proportion of all seeds. For small-seeded species both physical and biological processes may influence the secondary fate of seeds, however the relative importance of these processes is not well known. Seeds of the pioneer tree species Cecropia insignis (seed mass 0.5 mg), Trema micrantha (2.5 mg) and Apeiba aspera (14.2 mg) and five types of artificial seed were sown in understorey, treefall-gap and large-gap sites on Barro Colorado Island, Panama, during the wet season of 2005. Sowing areas were excavated after periods up to 26 d and cores divided into depths of 0–5, 5–10, 10–20 and 20–50 mm to allow high-resolution estimation of the rate and amount of burial and displacement of seeds. Over 26 d, 2.8% of artificial seeds were buried to a mean depth of 10.5 mm below the soil surface and 43.9% of unburied seeds displaced laterally >5 cm. Significantly more (87.9% and 80.9%) seeds of Cecropia insignis and Trema micrantha were displaced than artificial seeds of similar mass, size and density. A generalised linear model suggested that burial mostly occurred within 15 d, while displacement occurred continuously up to 26 d. The dominant cause of displacement and burial was probably rainfall, while seed removal by ants may also have contributed to displacement.

We investigated the effect of seasonality on tree phenology in the tropical montane rain forest of southern Ecuador and analysed possible triggering factors. Two hypotheses were tested: (1) Interspecific synchronization of flowering and fruiting phenology is higher at study sites with pronounced rainfall seasonality compared with sites within perhumid forests. (2) Proximate causes for flowering in closely situated seasonal and perhumid sites are either photoperiodicity or climatic factors. Two nearby study sites with contrasting precipitation patterns were selected at the same altitude east and west of the western Cordillera. Eighty trees from 13 species were observed over a 2.5-y period. Three species were common to both study sites. Phenological and climate data were collected and cross-correlated by conducting a time-series analysis. At the perhumid site, very clear annual patterns of phenological behaviour could be observed for most of the selected rain-forest tree species, but with a poor interspecific synchronization. On the nearby seasonal site in contrast, most species showed high synchrony in their phenological behaviour coinciding with the dry season. There is strong evidence that flowering is induced not by one factor alone: we identified photoperiodic control, radiation and precipitation as possible proximate causes for both sites. Our results confirm studies which state that these factors are closely linked to each other in the tropics.

The relationship between leaf longevity and other leaf traits was compared among different life-form categories (trees, herbs, climbers and epiphytes) of 101 plant species in a tropical montane forest on Mt. Halimun, West Java, Indonesia. We applied the Cox proportional hazards regression to estimate the leaf longevity of each species from 30 mo of census data. We examined whether estimated longevity was explained by either species life-form categories, taxonomic groupings (eudicots, monocots, magnoliids and chloranthales, and ferns) or such leaf traits as leaf area, leaf mass per area (LMA), mass-based leaf nitrogen, penetrometer reading, condensed-tannin-free total phenolics and condensed tannin. There was a wide-ranged interspecific variation in leaf longevity, mostly 10–50 mo, similarly across life-form categories. LMA showed a strong positive influence on leaf longevity. We found that relationships between leaf longevity and some leaf traits were different among various life forms. Trees tended to have high LMA, while climbers tended to have low LMA at the same leaf longevity. We hypothesize that such difference among life forms reflects shoot architecture characteristics. Multi-shoot trees with branching architecture need to have self-supporting leaves, whereas semi-epiphytic climbers can maintain relatively low biomass investment to leaves hanging or relying upon the mechanical support from host plants.

Some large-seeded tree species have cotyledonary reserves that persist for months after seedling establishment. We carried out two screened growing-house experiments with seedlings of Gustavia superba (Lecythidaceae) to test hypotheses proposed to explain why cotyledons are retained. We grew seedlings from large and small seeds in sun and shade to determine if cotyledon reserves supplement photosynthetic carbon gain, and in a second experiment applied defoliation and shoot removal treatments to determine if reserves are allocated to resprout tissue. In each experiment we tracked cotyledonary resource use over time and measured the fraction of seedling biomass allocated to roots and shoots. We found no evidence that light environment, seed size or damage treatment affected the rate of cotyledon resource usage; 20% of the cotyledonary mass remained 9 wk after leaves were fully developed in both sun and shade and 25–30% of the cotyledonary mass remained 6 wk after leaf or shoot removal. Instead, cotyledon reserves appear to be slowly translocated to roots regardless of light environment or seedling damage. Once seedlings are established, lost tissue is replaced using reserves stored in roots; in high light, damaged seedlings had a lower root mass fraction (0.42) than undamaged ones (0.56) when considering the mass of tissue removed and resprout tissue combined. We conclude that cotyledon reserves are important for resprouting during early seedling emergence and establishment, but do not directly contribute to seedling growth or biomass recovery from herbivores at the post-establishment stage. Persistence of cotyledons may ultimately depend on the development of sufficient root mass for reserve reallocation.

Although herbivores may account for a significant source of seed and seedling mortality in many tropical tree species, plant species differ in their response to seed damage. Here we investigate the relative effects of seed predation on the regeneration of five tree species in a mid-elevation Papua New Guinean rain forest. Exclosure treatments and shade-house experiments were monitored from November 2004 to March 2006 to assess the differential effects of seed predation on seed viability and seedling growth. Results indicate that although seed predators attack all five focal species, they influence the seedling populations in two, Cerbera floribunda and Microcos grandiflora, and minimally affect the seedling populations of Terminalia impediens, Pandanus penicillus and Endiandra latifolia in the years measured. Predation and germination frequencies were compared to the abundance of focal species at several life stage classes to explore potential correlations between species-specific seed mortality patterns and life stage distributions. We found that the species-specific influence of mammalian seed predators correlated with abundance distributions in three life stages. Species with high survivorship after seed predator attacks displayed a significant decrease in abundance from the seedling-to-sapling transition, while those species with high seed mortality demonstrated relatively even distributions of seedlings, saplings and adults (> 10 cm dbh). These contrasting patterns suggest that differential seed predation effects on regeneration may play a key role in the recruitment of individuals to the sapling stage.

Multimammate rats of the genus Mastomys are among the most widespread pest species in Africa. Previous studies of Mastomys population dynamics have generally reported variation in abundance but few have investigated the demographic parameters underlying this variation, and in particular recruitment. Capture-mark-recapture data were collected for Mastomys erythroleucus several times a year from 2000 to 2004 at a site annually flooded by the Niger River in Mali. Closed-population models were used to estimate population abundance. Both seniority (a parameter inversely linked to recruitment) and survival probabilities were estimated by capture-mark-recapture models. The impacts of water level, population abundance and cumulative rainfall were assessed for each demographic parameter. Survival probabilities (local survival) were negatively correlated with water level, suggesting that rodents emigrated out of the study zone during flooding. As for seniority probabilities, 86% of temporal variation was explained by a model with season, abundance, water level and the interaction between abundance and water level. This suggests that density-dependence in recruitment was mediated by intraspecific competition for food or refuge from floodwaters, or by predation. The flood of the Niger River greatly impacts Mastomys erythroleucus population dynamics, affecting both survival and seniority probabilities.

We irrigated and fertilized (with nutrients) seedlings of Doliocarpus olivaceus (Dilleniaceae, a shade-tolerant liana), Faramea occidentalis (Rubiaceae, a shade-tolerant understorey tree) and Tetragastris panamensis (Burseraceae, a shade-tolerant canopy tree) growing in the understorey of an old-growth tropical moist forest in Panama to assess the impact of seasonal water availability and nutrient-poor soils on seedling growth rates. In control plots, height growth rates were greater in the dry season than in the wet season for Doliocarpus (21%) and for Faramea (89%), whereas Tetragastris had similar seasonal rates. For numbers of leaves, Faramea had 3.5-fold greater relative growth rates in the dry season than in the wet season, while Doliocarpus and Tetragastris lost leaves (semi-deciduous) during the same period. Irrigation and nutrient augmentation increased height growth rates for all three species (45% to 272%). For Doliocarpus, irrigation and nutrient augmentation prevented leaf fall during the dry season. For Faramea in the dry season, irrigation and nutrient augmentation when applied independently reduced the growth of new leaves by 65% to 87%, but relative growth rates for number of leaves were the same as the control rates in the combined irrigation and nutrient augmentation treatment. The growth of new leaves for Tetragastris responded to dry-season irrigation but not nutrient augmentation. Although all measurements occurred beneath the forest canopy, during the dry season, Tetragastris had a negative relationship between canopy openness and relative growth rate for number of leaves, whereas the other two species had a positive relationship. Our results show that soil resources influence growth rates even in the deep shade of the forest understorey, and demonstrate different responses to soil resources among species that might contribute to niche differentiation and species coexistence.

Seed dispersal and predation by spiny rats (Proechimys semispinosus) and red-tailed squirrels (Sciurus granatensis) were studied in five forest gaps and adjacent forest understorey on Barro Colorado Island, Panama, during June and July 2003 and January 2004. Live trapping on grids was used to estimate the abundances of rats in both habitats and was conducted during 10 nights at the beginning of each field season. We captured 70 individual spiny rats (53 in forest gaps and 17 in understorey). To address the removal and dispersal of seeds, semi-permeable wire-mesh exclosures were set at randomly selected stations within the trapping grids. These exclosures allowed the entry of spiny rats, squirrels, and other small rodents but excluded larger granivorous mammals. Seeds were marked with pieces of string that were dusted with fluorescent powder and tracked at night with an ultraviolet light. A total of 304 seeds was removed (159 in forest gaps and 145 in understorey). Spiny rats removed more seeds from gaps, and squirrels removed more seeds from understorey. Both species dispersed more seeds during the rainy season than during the dry season. Squirrels dispersed seeds farther than did spiny rats. Due to their foraging behaviour and association with gaps, spiny rats may disperse seeds from forest understorey into gaps.

Habitat degradation affects mixed-species bird flocks (flock hereafter) through two mechanisms – changes in the bird community from which flocks are drawn and changes in the propensities of species to flock. We determined the relative influence of these two mechanisms by examining variation in flocks across nine rain-forest fragments (range 11–2600 ha) in a plantation landscape in the Western Ghats, India. We found differences between fragments in average number of species (range 10.8–15.2) and individuals (range 19.0–37.6) per flock, number of species that participated in flocks (range 34–59), encounter rates (range 0.5–2.4 flocks h−1) and flock composition. Multiple regression and randomization tests revealed that different mechanisms contributed to this variation. Three flock variables (open-forest individuals per flock, total open-forest species that participated in flocks in a fragment, flock composition) mainly reflected changes in the bird communities of fragments. Habitat structure strongly influenced three flock variables (open-forest species per flock, total and rain-forest individuals per flock) and flock composition to a lesser extent. Finally, flock encounter rate was strongly related to fragment area, but not to abundance of flock participants indicating habitat degradation-induced changes in propensities of species to flock.

We describe levels of parasitism of ectoparasitic bat flies (Hippoboscoidea: Streblidae) on male and female bats from an extensive Neotropical survey. The collection resulted from coordinated vertebrate-parasite surveys undertaken by the Smithsonian Venezuelan Project (SVP) from 1965–1968, which sexed 24 978 bats of 130 species. Streblid parasites were recovered from 6935 individuals of 87 bat species, but only 47 species were captured frequently enough (≥ 20 infested individuals) to permit reliable estimates of streblid parasitism on males and females. Well-sampled species included 39 phyllostomids, four mormoopids, two noctilionids, one natalid and one molossid. Prevalence of streblid parasitism (proportion of individuals infested) of male and female bats was generally not significantly different, and averaged 0.34 across infested species. In species-level analyses assessed against captures, significant sex differences in infestation levels were noted in six species; all had mean prevalence below 0.5 and females were parasitized disproportionately in each. Sex differences in total numbers of flies were noted in 21 species, and in 16 of these, females carried disproportionately heavy loads. Sex differences were also found for eight species of bat in the number of fly species infesting an individual; seven of eight showed heavier female parasitism. In analyses weighted by infestation levels, sex differences in total number of flies were found in only 12 species, with seven showing excessive parasitism of females, and no species showed sex differences in the number of fly species infesting them. These significant biases were not associated with sexual size dimorphism among the bat species. Generally higher levels of parasitism among female bats accords with theory, given their generally higher survivorship and enhanced probabilities of lateral and vertical transmission of host-specific parasites, but contrasts with patterns shown by many other parasitic arthropods. Future analyses should target social groupings of bats, not passively sampled foragers, to better address the mechanisms responsible for this pattern.

Litterfall quantity and quality may respond to alterations in resource availability expected with ongoing land-use and climate changes. Here, we quantify the effects of altered resource availability on non-woody litterfall quantity and quality (nitrogen and phosphorus concentrations) in eastern Amazonian forest regrowth (Brazil) through two multi-year experimental manipulations: (1) daily irrigation (5 mm d−1) during the dry season; and (2) fortnightly litter removal. Consistent with other tropical forest data litterfall exhibited seasonal patterns, increasing with the onset of the dry season and declining with the onset of the rainy season. Irrigation did not affect litterfall mass and had little impact on nitrogen (N) or phosphorus (P) concentrations and return, except for decreasing litter P concentration at the end of two irrigation periods. Litter removal did not alter litterfall mass or P concentration, but progressively reduced litterfall N during the course of the experiment. Overall, these results suggest significant resistance to altered resource availability within the bounds of our experimental treatments; our findings may help to constrain carbon and nutrient cycling predictions for tropical forests in response to land-use and climate changes.