Patterns of fruit production were monitored over a 1-year period, from June 1990–May 1991, by counting the numbers of freshly fallen ripe and unripe fruits on five 5-km line transects located within 35 km of one another, in lowland tropical rainforest in the Lopé Reserve, central Gabon. A total of 195 species of fruit were found, representing at least 45 taxonomic families. The majority of fruits came from trees. Fruits were assigned to one of six categories which reflected their dispersal syndrome: succulent, arillate, dehiscent, fleshy pods, wind-dispersed, others. About three-quarters of all species had fruits characteristic of those dispersed by animals. There was a marked seasonal pattern to fruit production, with both the diversity and number of ripe fruits available peaking in January, and lowest immediately before and during the major dry season. The only climatic variable that showed a significant statistical correlation with fruit production was insolation. Candidates for the role of keystone fruit species were identified from species which fruited during the major dry season, and patterns of fruit production compared with other areas.

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.

Patterns of bird species diversity within three vegetation types were investigated by the line transect method on Mundanthurai Plateau, South India. Minimum numbers of species and individuals were seen in the study area during July and August. Such seasonal variation was more pronounced in riverine and dry deciduous forest than in the secondary vegetation which was avoided by most of the winter migrants. There was a greater species overlap between riverine and dry deciduous forest than between riverine and secondary vegetation.

No relationship could be established between bird species diversity and tree species/foliage height diversity. The secondary vegetation had fewer specialized forest species and more generalists. Larger birds (>200 g) were rare but smaller ones (<50 g) were more common. The paper emphasizes that the conservation status of avifauna in managed forests in India needs to be assessed and monitored.

The wet evergreen forest of Nelliampathy in the Western Ghats of Kerala in India is a mixed forest with a high species diversity and basal cover. In this relatively undisturbed ecosystem, canopy gaps are largely formed through single tree fall, but gaps through branch fall, crown fall, standing dead trees or multiple tree fall also occur. Canopy gap formation is more (over 82% of the total gaps created) during the monsoon season. The mean number of gaps formed in this forest is 1.13 ha−1 y−1 and the turnover rate is 83 years. The majority of the gaps created (over 70%) are of smaller size (≥ 100 m2). In this forest, while some top canopy tree species (those capable of exceeding 25 m in height at maturity) such as Palaquium ellipticum and Mesua nagassarium are well represented in seedling, sapling and mature tree stages, others like Aglaia exstipulata and Mastixia arborea are observed only as saplings and/or mature trees with no seedling populations. The possible reasons for these two types of regeneration behaviour by top canopy tree species in the context of canopy gap size and seasonality in gap formation are discussed.

The role of chimpanzees (Pan troglodytes) as seed dispersers in the Kibale Forest Reserve of western Uganda was assessed by analysing 1849 dung samples from two chimpanzee communities and by conducting germination trials on dispersed and non-dispersed seeds. Of the chimpanzee dung samples, 98.5% contained seeds, and fig seeds were the most common. The number of large seeds (>2 mm) per dung sample was often high, even for species with a relatively large seed. For example, Mimusops bagshawei has a 15-mm diameter seed and had an average of 26.5 seeds per sample. In addition, many seed species were found in the dung repeatedly over several months. Germination trials demonstrated that the species of seed commonly collected from dung were viable. Comparisons of both the rate and success of germination of chimpanzee-dispersed seeds with seeds collected directly from the parent trees, showed that gut passage increased the speed and probability of germination. The number of large seeds dispersed by the chimpanzee population was estimated at 369 large seeds km-1 day-1. We suggest that in Kibale, chimpanzees may play a more significant role in primary seed dispersal than implied by their low numbers and biomass.

A study of seedling demography of three shade-tolerant canopy tree species (Quararibea asterolepis, Trichilia tuberculata, and Tetragastris panamensis) was initiated to integrate with long-term studies of tree fruit production and of tree population dynamics on Barro Colorado Island, Panama. Over a five-year period, all seedlings (height <50 cm) and small saplings (height ≥50 cm to dbh 1 cm) were measured and monitored in permanent tree-centred transects (N = 10–11 trees per species). Survival rates increased with plant size class and were similar among species. Maximum height growth rates increased with increasing plant size, but average growth rates did not; this disparity suggests the importance of release from understorey suppression for long-term recruitment success. Among the three species, Quararibea had the lowest standing seedling densities and almost no sapling recruitment, whereas Tetragastris had the highest densities of both seedlings and saplings; Trichilia seedling and sapling densities were intermediate. In all three species, a few trees produced very high seedling and sapling densities in comparison with the sample average. All three species exhibited a year of exceptionally high new seedling recruitment during the study period; these good years were not coincident among the species but instead reflected the species' phenological differences. Since seedling survival becomes relatively constant and high after the first few years of life (c. 80% y−1), such large new cohorts persist as a year-class effect in the seedling population and thus maintain seedling numbers over time. The interspecific differences in seedling and sapling dynamics were consistent with overall 10-year trends of a declining Quararibea population, a stable Trichilia population, and an increasing Tetragastris population.

The spatial distribution of canopy gaps was analysed on three sites (total 71 ha) in the tropical moist forest of Tai National Park, Ivory Coast. Pattern analysis revealed a clustered distribution of gaps for two of the three sites. Catena dependent gap formation processes might explain local differences in the occurrence and distribution of gaps. Gap densities, sizes and percentage forest area in gap phase are higher on the upper and middle slope than on the crest or lower slope. As a consequence, regeneration of gap dependent tree species might be directed to the catena positions with the highest disturbance regime. The spatial distribution of gap dependent species can be clumped, not only due to the regeneration within gaps, but also due to the clustered nature of gap distribution on its own.

Seasonally flooded forests represent a transition between terrestrial and aquatic ecosystems. The Mapire river, a tributary of the Orinoco river, floods its surrounding forests during the wet season (May–December). The soils are very acid and the total nitrogen concentration (0.1%) is only half that found in nearby soils flooded by Orinoco waters. Ammonium-nitrogen predominates in the soil during the flooded period while nitrate-nitrogen concentrations are higher in the dry period. Wide fluctuations in the inorganic nitrogen fractions did not considerably affect the annual course of soil nitrogen.

The predominance of mineralization versus nitrification (56 and 5 μg soil month−1 respectively) and possibly the synchronization of nitrogen availability with plant demand could be considered as nitrogen conserving mechanisms.

In synchrony with the hydrologic cycle, the seasonally flooded forest studied shows a nitrogencycle where inputs and accumulation are maximized when the system is under minimum stress (dry season). During flooding, the system enters a period of dormancy making minimal use of nutrient and energy to avoid or tolerate anaerobiosis.

The populations of two dominant isopod species in a Pinus merkusii forest on the southern slope of mount Ungaran in central Java, Indonesia, were periodically sampled during one year using Tullgren extractions from soil cores. The aim of the research was to collect more information about the life-cycles of tropical isopods by analysing size-class distributions of two sympatric isopod species, belonging to the genus Burmoniscus. Biomass of the populations was estimated from length-weight conversions established for each species in the laboratory. The efficiency of the Tullgren extraction method was estimated by comparison to hand sorting; no difference was found between these methods.

The abundance of the two species differed significantly with time. Burmoniscus Sp. A was more abundant during the wet season, whereas the population fluctuations of Burmoniscus Sp. B were more spread over the year. Reproduction of both species took place in the wet season. Burmoniscus Sp. A had one generation per year, while for Burmoniscus Sp. B the situation was unclear due to extensive overlap of size classes. Comparisons were made with isopod abundance in other tropical and temperate forests. The mean density of the two species found in this study was 258 m-2 for Burmoniscus Sp. A and 272 m-2 for Burmoniscus Sp. B, while biomass was 80.4 mg m-2 and 37.6 mg m-2, respectively. The data suggest that densities of isopods in tropical pine forests may be considerably higher than in comparable temperate ecosystems.