Landscape-scale studies of community traits such as species richness and community composition are sorely needed to explore the impact of large-scale disturbance events such as ENSO (El Niño Southern Oscillation)-induced burning and habitat isolation on rain-forest communities. Here we assess butterflies in continuous forest, in unburned isolates surrounded by burned forest and in burned forest, in addition to areas sampled before the most recent (1997/98) large-scale burn event in Borneo. Overall levels of species richness were significantly higher pre-ENSO and in continuous forest than in unburned isolates and burned forest. There was, however, some variation among butterfly families in these patterns, with no significant differences among habitats (continuous forest, isolates and burned forest) for the Hesperiidae and significant differences for the other butterfly families. Patterns of community composition showed that similarity was greater between distant continuous forest and isolates than between either of these and burned forest. Since the unburned isolates were surrounded by the burned forest this indicates that the habitat (burned or unburned) overrides geographical differences. Dominant species that contributed substantially to differences among habitats were often completely absent from either burned or unburned forest. The combined patterns of species richness and community structure suggest that burning affects forest ecosystems by a replacement of dominant species while habitat isolation may affect areas by leading to the local extinction of rare species.

The reproductive biology of the dioecious understorey palm Chamaedorea radicalis was investigated in order to identify the primary pollen vector and quantify the relationship between female fecundity and local neighbourhood sexual composition. The study was conducted in a montane mesophyll forest within the El Cielo Biosphere Reserve, Tamaulipas, Mexico. The species is considered vulnerable in Mexico and there are concerns about the sustainability of leaf harvest. We determined that wind is the primary pollen vector, based both on floral and pollen morphological characters, and on a pollinator exclosure experiment. Successful wind pollination of this understorey palm was facilitated by the extended flowering period of males, which allows one male to be a source of pollen to receptive females for as long as a month. The number of flowers and fruits borne on a female were dependent on female size, however, no size parameter correlated well with fruit set. Fruit set was also not dependent on local sexual composition, male density or distance to the nearest male, suggesting that in this study area female reproductive success is not limited by the availability of pollen.

Dryobalanops rappa (Dipterocarpaceae), a dominant tree in wetland forests in Borneo, often produces vegetative sprouts in its juvenile stages (trees less than 25 m in height), a characteristic that is believed to be rare in tropical forest trees. We investigated the growth characteristics of this species in a tropical forest in Merimbun Heritage Park, Brunei, to verify the hypothesis that the vigorous sprouting ability enables it to grow in a wetland forest with soft soils that promote stem decumbency and to assess the adaptive significance of vegetative sprouting in the context of its regeneration. Reproductively mature trees developed buttresses and were rarely decumbent. However, if they became decumbent, they died without sprouting. Juvenile trees were frequently decumbent, and their decumbent shoots sprouted vegetatively. Therefore, vegetative sprouting acted as a countermeasure to decumbency and death on the soft wetland soil. A decumbent shoot produced only one sprout in most cases. Decumbent shoots grew little and eventually died, but new sprouts showed rapid growth. This suggests that there is translocation of resources from decumbent shoots to sprouts. If decumbency occurs, a D. rappa genet ramifies into sprouts, and helps sustain the population in the wetland environment. This vegetative life history strategy is important for regeneration in wetland forests with soft soil.

The impact of seed size on germination and seedling growth, as affected by water stress, was studied for five tree species from tropical dry forest of India, viz. Albizia procera, Acacia nilotica, Phyllanthus emblica, Terminalia arjuna and Terminalia chebula. Germination tests were conducted under five osmotic potential levels. Seedlings from large (LS) and small (SS) seeds were grown at four soil moisture levels. Observations were made on height, leaf area, biomass and other growth traits such as relative growth rate (RGR), net assimilation rate (NAR), specific leaf area (SLA), and root:shoot (R:S) ratio. Seeds of pioneer species and large seeds, within species, germinated earlier, and with increasing water stress, per cent germination and germination velocity declined. RGR was inversely related with drought tolerance. R:S ratio increased, RGR and SLA declined, but NAR increased with water stress. Notwithstanding successional status, the slow-growing species registered minimum reduction in biomass due to water stress. The response of LS and SS seedlings also differed for some of the growth variables. Increase in NAR could be a compensatory response to water stress, and the marked allocational plasticity could help maximize capture of the limited resource. Seedlings from smaller seeds, particularly of fast-growing species, would be able to cope with mild drought by morphogenetic and physiological plastic response in a better way than those from large seeds. However, seedlings from large seeds had greater survival than those from smaller seeds under intense water stress.

We studied activity patterns and habitat use by insectivorous bats in Comoé National Park, Ivory Coast. Bat foraging activity was quantified along five transects representing three different habitat types using acoustic monitoring and captures with mist nets and harp traps. Aerial insect abundance was assessed using a light trap; in addition shrub and tree arthropods were sampled. Bat activity was significantly and positively related to insect availability and ambient temperature, whereas increased visibility of the moon had a negative influence on flight activity. Together, these factors best explained both total bat activity and activity of bats hunting in open space and edge habitats. The interaction between temperature and light intensity was the best predictor of activity by species foraging in obstacle-rich forest habitats, however, the regression model had a low predictive value. Overall, a large proportion (c. 50%) of the variation in bat activity appeared to be a consequence of transect- and/or habitat-specific influences. We found a significant non-linear relationship between the activity of QCF (quasi-constant frequency) and FM–QCF (frequency modulated – quasi-constant frequency) bats and the phase of the moon, with lowest levels of activity occurring near full moon. We interpret this lunar-phobic behaviour as a reflection of a higher predation risk during moonlit periods. For FM (steep frequency modulated) and CF (constant frequency) bats, no significant correlation was found, although there was a trend suggesting that these bats at least were not negatively affected by bright moonlight. Foraging activity of bats was positively correlated with the abundance of atympanate moths; however, no such correlation was found for tympanate moths.

On 31 December 2001, Tropical Cyclone Waka passed directly over the Vava'u island group, Kingdom of Tonga, with sustained and maximum wind speeds of 185 km h−1 and 230 km h−1 respectively. During a prior study of forest secondary succession, 44 forest plots on 13 islands had been surveyed in 1995 and their locations marked. Nineteen of the plots were resurveyed and two additional transects established in May–June 2002, 6 mo following the cyclone. Cyclone-related tree mortality averaged 6%, varied from 0–7% for lowland late-successional species, and tended to be higher for early successional plots (8–16%) and species (4–19%). Severe damage (uprooting, snapped stems) affected 25% of the 2030 stems measured. The proportion of snapped stems was disproportionately high in the 10–15-cm stem diameter class. Uprooting was more prevalent than expected by chance among larger trees (>20 cm diameter). The greatest mortality and severe damage (combined,>35% of stems) occurred in plots that were early successional. Over the 6 y prior to the storm, background recruitment and mortality averaged 1.4% and 3.3% respectively. Mortality was greater than recruitment, while basal area was increasing, in most plots that had not experienced additional anthropogenic disturbance.

We investigated the seed dispersal of Aglaia spectabilis, a large-seeded tree species in a moist evergreen forest of Khao Yai National Park in Thailand. Although one-to-one relationships between frugivores and plants are very unlikely, large-seeded plants having to rely on few large frugivores and therefore on limited disperser assemblages, might be vulnerable to extinction. We assessed both the frugivore assemblages foraging on arillate seeds of Aglaia spectabilis and dispersing them and the seed predator assemblages, thereby covering dispersal as well as the post-dispersal aspects such as seed predation. Our results showed that frugivores dispersing seeds were a rather limited set of four hornbill and one pigeon species, whereas two squirrel species were not dispersers, but dropped the seeds on the ground. Three mammal species were identified as seed predators on the forest floor. Heavy seed predation by mammals together with high seed removal rates, short visiting times and regurgitation of intact seeds by mainly hornbills lead us to the conclusion that hornbills show high effectiveness in dispersal of this tree species.

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.

The habitat associations of stream-breeding frogs were examined along a series of stream transects on Buton Island in south-east Sulawesi, Indonesia. Of the eight frog species located along streams, four were observed breeding in stream habitats. We examined spatial habitat partitioning among these species. Three of the four species were found to be associated with a non-random selection of the available perch sites. Strong partitioning between species in habitat associations was found; partitioning of the available habitat space was primarily associated with differences in proximity to stream features, and in the height of perch sites. General observations indicated that oviposition sites of most species were associated with the microhabitats in which the adult frogs were found. All four stream-breeding species appear to have synchronous breeding phenologies and the spatial relationships of these species within the habitat space appear to reflect partitioning of calling sites and oviposition sites. The stream-breeding frog community in this region of Sulawesi has much lower species richness and less specialized habitat use compared with other tropical stream-breeding frog communities in the region.

Early successional tree species typically attract numerous generalist frugivores, many of which serve as seed dispersers. This study evaluated whether several such dispersers facilitated the invasion of an exotic, early successional tree species, Maesopsis eminii (Rhamnaceae), in submontane forests of the East Usambara Mountains, Tanzania. The primary seed dispersers and their dispersal effectiveness were determined through focal watches at eight trees. Only 3 of 13 frugivores that consumed Maesopsis fruits functioned as seed dispersers (silvery-cheeked hornbill Ceratogymna brevis, Fischer's turaco Tauraco fischeri and blue monkey Cercopithecus mitis). On average, hornbills dispersed >26 times more seeds than monkeys, and >3 times as many seeds as turacos per visit and were thus considered the most important disperser. Seed germination was not affected by gut passage through hornbills. Germination in four microhabitats was experimentally evaluated to determine whether microhabitat influences germination success. Large gaps and forest edges had significantly higher germination rates compared with understorey locations; the germination rate in small gaps was not significantly different from that in the understorey. Expansive Maesopsis invasion in the East Usambaras was likely enhanced in both rapidity and scale by the presence of an extremely effective dispersal agent, the silvery-cheeked hornbill.

This study describes a pollination system in a species of Araceae that involves three species of beetle, one of which is also a fruit predator. In a tropical cloud forest in Colombia, inflorescences of Xanthosoma daguense opened at dusk, releasing a sweet scent and raising their temperature 1–3 °C. Soon after, two species of Scarabaeidae (Dynastinae; Cyclocephala gregaria and C. amblyopsis) and one species of Nitidulidae (Macrostola costulata) arrived with pollen. Cyclocephala beetles remained inside the inflorescence for 24 h. The next night, Cyclocephala beetles left the inflorescence after picking up the freshly shed pollen, almost always moving to the nearest inflorescence available. The probability of inflorescence abortion and number of fruits set after the visit of one individual was equivalent for both Cyclocephala species. However, C. gregaria was much more abundant than C. amblyopsis, so it was the most important pollinator. There was a positive relationship between the number of dynastine visits and the number of fruits produced. Besides carrying pollen to the inflorescences, nitidulid beetles had a negative effect on female reproductive success through fruit predation. Nitidulid larvae developed inside the infructescence and preyed on up to 64% of the fruits. However, 8% of inflorescences not visited by dynastines were probably pollinated by nitidulids, because hand-pollination experiments showed that self-pollination was unlikely. Inflorescences potentially pollinated by nitidulids comprised 25% of the fruit crop in the year of our study. This interaction with a fruit predator that is also a potential pollinator resembles brood-site pollination systems in which pollinators prey on part of the fruit set (e.g. Ficus, senita cacti, Yucca), making this system substantially more complex than previously described dynastine-pollinated systems in aroids.

Over recent decades, studies on post-dispersal seed predation have revealed some general patterns despite dealing with a highly variable phenomenon (reviews in Crawley 1993, Hulme 1998). Most of these studies, however, were carried out with plant species whose population density range from low to moderately high (Hulme 1998). Only rarely has seed predation been studied in very dense stands of a given plant species (Schupp 1988a, b, 1992). In such a situation, seed predators might respond to the local availability of seeds in a manner that differs from their response under conditions of low seed density. For instance, a high density of seeds beneath a fruiting plant may attract seed predators, causing a positive correlation between predation and seed density (Janzen 1970). Schupp (1992), however, noted that at a population scale, a high density of seeds could satiate predators, resulting in a negative correlation between predation and seed density (see also Burkey 1994).

Prey depletion is a major (but often neglected) factor driving the current decline of tigers (Panthera tigris L.) (Karanth & Stith 1999). Thus conservation planning for the tiger in a fragmented, human-dominated landscape requires reliable information on prey densities from various parts of its range. We report numerical and biomass density of six herbivores from the tropical dry-deciduous forests of Ranthambhore Tiger Reserve (RTR, 26°N and 76°E), Rajasthan, India, where these are important prey for tigers (Bagchi et al. 2003).

Rainfall fluctuation influences the physiology and leaf production of the trees in tropical rain forests (Burslem et al. 1996, Condit et al. 1995, Reekie & Wayne 1992, Reich 1995), and consequently it may have an impact on the community of herbivores that depend on forest trees for their food resources (Aide 1988, 1992; Basset 1991, Coley 1998, Lowman 1985, van Schaik et al. 1993).

Tropical forests can recover after anthropogenic disturbances of light to moderate intensity (Aide et al. 1995, 1996, 2000; Uhl 1987, Uhl et al. 1988); however, severe disturbances (e.g. compaction or loss of soil) often result in conditions that prevent forest recovery. These degraded sites are often dominated by grasses (Aide & Cavelier 1994, Cabin et al. 2002, Cavelier et al. 1998, Uhl et al. 1988) and ferns (Cohen et al. 1995, García et al. 1994, Slocum et al. 2000, Walker & Boneta 1995) that can impose barriers for tree regeneration and arrest the succession process. Important barriers for tree regeneration include: (1) competition with grasses and ferns for soil moisture, nutrients and light (Aide & Cavelier 1994, Guimarães-Vieira et al. 1994, Holl et al. 2000, Nepstad et al. 1996, Russell et al. 1998, Walker 1994, Zimmerman et al. 2000), and (2) dispersal limitation given that grasses and fernlands offer few resources that attract seed dispersers (Guevara & Laborde 1993, Holl et al. 2000, McDonnell & Stiles 1983, Slocum & Horvitz 2000, Zimmerman et al. 2000).