Patterns of population fluctuation, reproductive activity and age structure were studied in populations of the marsupial Micoureus demerarae occupying two small (7.0 and 8.8 ha) fragments of Atlantic Coastal Forest in southeastern Brazil, from 1995 to 1998. Males, but not females, were observed to move between populations. Estimated sizes of the populations in each fragment were very small, usually below 20 individuals. Breeding usually occurred from September to April. Population peaks came mostly by the end of this season, the delay reflecting the time required for the young to become trappable. In August 1997, the area was hit by a fire severely affecting the smaller fragment. Populations were synchronous before the fire, although they became asynchronous after it, possibly in the short term only. Small population sizes, synchrony and presumable male-biased migration are all likely to make the set of populations more vulnerable to extinction than expected for a metapopulation.

The influence of a rainfall gradient on the distribution and species richness of some groups of wood-inhabiting basidiomycetes was explored in Costa Rican tropical forests. The relationships between these fungi and wood size and decay stage were also studied. Basidiocarps of all poroid and some corticoid fungi were recorded in three plots of 30 logs in each of dry, moist, and wet forests. The logs were surveyed three times during one year, covering all seasons. The species richness gradient was inversely related to the rainfall gradient, with most species in the dry forest (51), least in the wet forest (37), and intermediate in the moist forest (44). A total of 102 species were identified. Only six species occurred at all three sites. Two of the four most common species were new to science. The composition of wood-inhabiting fungal species in the dry forest varied from both the moist and the wet forest, while species composition in the two latter forest types was difficult to distinguish. Both frequent and rare species utilized the different decay stages as expected from availability of substrate. Perennials and rare species tended to occur on large logs in the dry forest, while all species tended to occur on large logs in the moist forest, but not in the wet forest.

We studied the resource allocation process of a large-seeded species, Dryobalanops lanceolata, during germination and early stages of seedling growth in Sarawak, East Malaysia. The seeds contained high contents of starch (74.3% of the total 1.57 g mean dry weight of the cotyledon) and lipid (15.0%). All of these reserves were exhausted by the time the first two pairs of leaves had developed (about 40 d after planting), but relatively little had been reserved in leaf or root by that time. This suggests that the large amount of seed reserve of D. lanceolata is necessary just to form a certain size of stem and the necessary number of leaves to set the plant up for photosynthesis. After seed reserves were exhausted, shoot elongation and new leaf production stopped, and most photosynthate was allocated to the expansion of the root system and to storage in the root as starch. The storage reserves in the root are thought to be used for the next growing stage, not to act as insurance for sprouting in case of shoot damage.

In 1998 a survey was made of the termites of the Leuser Ecosystem (in Sumatra, Indonesia), which includes a substantial area (c. 1 million ha) of unbroken primary rain forest. Nine sites and an altitudinal gradient were sampled. Altitude had a significant effect on species richness, which declines with even a 100-m increase in altitude. Species composition too was significantly affected by altitude. Functionally, only termites in one feeding group (II, which forage outside of their nests) were significantly affected by altitude. A mid-altitude termite species assemblage was evident. Longitude also significantly affected species composition; Macrotermitinae were numerous on the western side of the Ecosystem and Termitinae and Nasutitermitinae more numerous to the east of it. This was probably due to differences in rainfall patterns across the Ecosystem.

In a 30-ha permanent plot of tropical evergreen forest at Varagalaiar, Indian Western Ghats, all trees ≥ 30 cm girth at breast height (gbh) were examined for the presence of lianas ≥ 1 cm dbh. The plot contained 13 445 trees in 152 species and 11 200 lianas in 75 species. Twenty-eight per cent of trees supported lianas and the mean number of lianas per tree was 0.38 ± 0.72. Association analysis between lianas and trees of 16 tree families and 20 abundant tree species indicated that tree susceptibility to lianas was better pronounced at species rather than at family level. Overall, at Varagalaiar site, the aggregation of lianas followed neither Poisson nor clumped distribution. Among the four dominant tree families Dipterocarpaceae and Clusiaceae fit to the negative binomial model better than Euphorbiaceae and Meliaceae. These four families differed in their susceptibility level with 34.6% , 36.7% , 24.1% and 27.7% of trees ≥ 30 cm gbh respectively supporting lianas. At the species level, the proportion of trees with lianas was positively correlated with the mean branch free bole height of trees ≥ 30-40 and ≥ 40 cm gbh classes, and the mean number of lianas per tree was also positively correlated with the mean branch bole height of trees ≥ 30 cm gbh. Of the 16 abundant families, Euphorbiaceae contributed 31% and dominated the lower canopy, but its susceptibility to lianas was lower when compared to most other families.

Geometroid moth abundance, species richness, weather and plant phenology were monitored monthly for 3 y in the lowland dipterocarp forest at Pasoh Forest Reserve, Negeri Sembilan in Malaysia. The intensity of tree flowering in the previous month (with mass events triggered in response to El Niño Southern Oscillations) was an important environmental factor positively correlated with the numbers of species and individuals of geometroid moths that emerge in any month. Abundance for geometroid moths was greater in months with high flowering and flushing in the previous month but low flowering in the month before that. Important weather parameters that influenced moth abundance were monthly rainfall, relative humidity and minimum temperature in previous months. High rainfall 3 mo previously led to an increase in moth abundance (perhaps by stimulating an increase in fresh plant material), whereas high rainfall and relative humidity thereafter served to decrease abundance, possibly by encouraging the spread and activity of pathogens: all these factors impacted on early life-stage survivorship. Similar trends were observed for individual geometroid families and subfamilies. The diversity measurement for the geometroid moths, α from the log-series, was correlated more with weather parameters than with tree phenology.

Pollinator visitation to, and the reproductive success of, Sonneratia caseolaris (Sonneratiaceae) and Aegiceras corniculatum (Myrsinaceae) was investigated in a mangrove forest in India. S. caseolaris was shown to be primarily outcrossed and A. corniculatum was shown to be a selfing species. The flowers of both plant species attracted several diurnal and nocturnal visitors. Earlier reports had indicated that S. caseolaris flowered for one night and was exclusively night-pollinated. But flowers of this species were found to be in bloom both at night and during the day, and diurnal visitors to the flowers were more diverse and frequent than nocturnal ones. This was related to the higher volume and energy value of nectar in the morning. The effects of time of day and temperature on visitation rates were quantified. The importance of visitors to plant reproductive success was investigated via controlled visitor-exclusion experiments. Pollinators were expected to be more important for the outcrossing species than for the selfing species, and this was confirmed by the results of the exclusion experiments. In S. caseolaris reproductive success was determined both by pollinator availability and the intensity of flower and fruit predation, while in A. corniculatum it is likely to be resource limited.

The dispersal system of Palicourea rigida (Rubiaceae), a common woody species of neotropical savannas, was studied in a seasonal Venezuelan savanna. Production and consumption of fruits, dispersal agents, feeding behaviour, transport and effects on seed viability, were investigated by field observations, cage experiments and viability tests. To compare different dispersers, quantitative and qualitative dispersal parameters were calculated. About 59% of the fruit crop was dispersed successfully by birds. Although 10 different bird species consumed the fruits of Palicourea rigida, three bird species dispersed 79% of the fruits (Tyrannus melancholicus, Molothrus bonariensis and Elaenia chiriquensis). T. melancholicus (Tyrannidae) was the most important dispersal agent, with more than 39% of dispersed seeds. In contrast to the predictions of the specialization vs. generalization paradigm, this system achieves high effectiveness by means of predominantly unspecialized traits in both the plant and the dispersers.

Se estudió el sistema de dispersión de Palicourea rigida (Rubiaceae), una leñosa común de las sabanas neotropicales, en una sabana estacional de Venezuela. Mediante observaciones de campo y experimentos en jaulas y en el laboratorio, se estudiaron paramétros tales como producción, transporte y consumo de frutos, los agentes dispersores y su comportamiento y los efectos sobre la viabilidad de las semillas. Para comparar los agentes de dispersión se estimaron paramétros cualitativos y cuantitativos. Cerca del 59% de la cosecha total de frutos fue dispersada existosamente por pájaros. Aunque los frutos fueron consumidos por diez especies de aves, el 79% de los frutos fueron dispersados por solamente tres especies (Tyrannus melancholicus, Molothrus bonariensis y Elaenia chiriquensis). T. melancholicus (Tyrannidae) fue el más importante agente dispersor con más del 39% del total de semillas dispersadas. En contraste con el paradigma de especialización vs. generalización, este sistema alcanza alta efectividad pero se caracteriza por rasgos poco especializados, tanto en la planta como en los dispersores.

The development of a given species in a natural forest depends on a multitude of factors. Insects are one of the factors that have an important impact. We would like to present initial observations about the behaviour of longicorns of the Onciderini tribe and their impact on the development of Dicorynia guianensis.

A study of the development of D. guianensis was conducted in French Guiana (5°18'N, 5°48'W), at the Paracou silvicultural facility. We studied plots where the Dicorynia inventory was extended to trees 1 m tall or over. In order to describe the impact of longicorn activity on a Dicorynia stand in which spatial distribution is aggregative (Kokou 1992), we chose trees (156 observed trees) in a control plot (plot 11, area: 17 500 m2). Height, trunk basal diameter and DBH were measured on each tree. A precise morphological description was established for each tree. It was during morphological description that the signs of longicorn attacks were sought. In all the species of the genus Oncideres, the female girdles the tree by removing the bark and some of the wood using its mandibles. It then digs deep into the wood above the cut and lays its eggs. The branch then breaks and falls to the ground (Hequet 1996). All that is left on the tree is a stump with characteristic signs of insect activity (Figure 1a). When such signs were seen on a plant, the type of structure (trunk, branch) was noted.

Rodents in tropical Africa have been recognized for decades both as important pests of agriculture and as reservoirs of numerous diseases that affect humans and livestock (Keesing 2000). Despite this recognition, however, little is known about the ecology and behaviour of these abundant and widespread animals. Because the impacts of small mammals as pests are expected to be some function of their population density, most ecological research on African rodents has focused on their population dynamics (Delany 1972, 1986; Leirs et al. 1994, 1996a).

The importance of disturbances for the dynamics of tropical forests has been described by Whitmore & Burslem (1998). Among the phenomena which they classify as large scale disturbances are those caused by wind. The most extensive of these occur within the hurricane (cyclone) belt (10-20° from the equator) but outside this belt large blowdowns of trees are known to occur, perhaps most spectacularly in the Brazilian Amazon (Nelson et al. 1994). There is evidence that rare wind storms influence the dipterocarp rain forests of Peninsular Malaysia, 2-6°N. One famous storm in November 1880 which devastated hundreds of square kilometres of forests in Kelantan, north-east Malaya, was probably an aberrant cyclone (Wyatt-Smith 1954). Smaller windstorms which have blown down several hectares of forests have been reported from Malaysia including Borneo (Ashton 1993) but their frequency and extent have not been well documented (Whitmore & Burslem 1998). At Barito Ulu, Central Kalimantan, one such storm occurred recently and the fortuitous combination of a well patrolled trail system and the localization of the storm has allowed a detailed assessment of the forest damage.

Given their difficulty of access, the canopies of tropical rain forests are considered a last frontier of biological/ecological research (Lowman & Nadkarni 1995). Climbing techniques are arduous and do not reach the tips of branches; towers, cranes and walkways limit the spatial exploration of the forest.

The Abstract and Table 2 within this paper contained some errors. The corrected versions appear below. The publishers would like to apologise to their readers for these errors.