Using 14C dating, the life span and growth rate of Borneo ironwood (Eusideroxylon zwageri, Lauraceae), which is a canopy tree species with extremely durable and decay-resistant wood distributed in tropical rain forests of South-East Asia, were studied. Timber segments collected from 15 logged stumps in Kubah National Park, Sarawak, Malaysia, were analysed by accelerator mass spectrometry and the obtained data were calibrated to determine the age of individuals. The 14C dating turned out to be an effective method for estimating ages of long-lived trees, such as E. zwageri, in the aseasonal tropics because the estimated error was small compared with estimated age. We found that E. zwageri can live more than 1000 y and that the growth rate of this species was very slow, with a mean radial growth rate of 0·058 cm y-1. The life span was much greater and the growth rate was much slower than those observed or estimated for trees of Dipterocarpaceae, the dominant family in this tropical forest. The long life span of this species may be caused by wood durability with a high specific gravity and abundant defensive compounds. Given equal carbon allocation, the high density and carbon-based defensive compounds may result in a reduced growth rate.

An analysis of corticolous bryophyte diversity on whole trees in primary rain forest and 4-15-y-old fallows at 500-650 m in the Alto Beni, Bolivia, showed a significantly decreased diversity of bryophyte families and moss species in the fallows. However, liverwort diversity was scarcely lower in the fallows, except in the very young (4 y old) ones. Fallows had a significantly higher percentage of smooth mat species (72%), which may reflect the warmer, drier microclimate in the fallows. About half of the bryophyte species of the rain forest had re-established in the 10-15-y-old fallows. The majority of these are ecological generalists and sun epiphytes; a small minority are shade epiphytes. Re-establishment of ecological specialists is slower than that of generalists. Species richness in the primary forest is highest in the canopy; in the fallows it is highest in the understorey due to striking shifts of species and specialized growth types (rough mats, fans, tails) towards lower heights on the trees in the fallows. These shifts correspond well with measured changes in air temperature and air humidity in the fallows as compared with the forest.

Effects of seed passage through digestive tracts of principal animal dispersers (bats and birds) on seed germination were investigated for two columnar cactus species, Stenocereus griseus and Subpilocereus repandus. In general, seeds ingested showed more rapid germination times and higher overall germination rates than untreated seeds. The bat Glossophaga longirostris, and the birds Mimus gilvus and Tachyphonus rufus seem to be the most efficient cacti dispersers in terms of quality of treatment. The increment of germination speed and particularly the decrease of imbibition time, could favour the probability of germination in dry areas such as arid and semi-arid environments.

We examined the distribution, germination, growth and photosynthetic characteristics of two co-existing morphotypes of the pioneer tree Trema micrantha at the Barro Colorado Nature Monument (BCNM), Panama. Morphotypes differed significantly in distribution and in seed characteristics. A ‘large’-seeded morphotype (endocarp mass=3.83 mg) was associated with treefall gaps in the forest interior, whereas a ‘small’-seeded morphotype (endocarp mass=1.38 mg) was found predominantly on landslides on the margins of Lake Gatun. Seeds of the small-seeded morphotype germinated faster than seeds of the large-seeded morphotype, with seedlings of the small-seeded morphotype showing both a higher Unit Leaf Rate (ULR) and a lower Specific Leaf Area (SLA). Differences in photosynthetic rates reflected differences in SLA; the small-seeded morphotype had a higher rate on a leaf area basis, while the large-seeded morphotype had a higher rate on a leaf mass basis. Although allocation patterns between morphotypes varied in a way consistent with known interspecific differences between ‘sun’ and ‘shade’ plants, relative growth rates (RGR) of the morphotypes were similar across different light conditions suggesting that factors other than light, such as water uptake efficiency, soil nutrient requirements, and perhaps seed dispersal characters may explain the habitat partitioning of morphotypes.

We investigated the effects of rainfall on the distribution and abundance of the satyrine butterfly Ragadia makuta in selectively logged and unlogged forest on Borneo. In 1997-98, there was a severe El Niño-Southern Oscillation (ENSO) drought, and annual surveys over a 4-y period showed that abundance of R. makuta was greatly reduced during the drought, but that populations quickly recovered after it. Monthly surveys over a 12-mo period of typical rainfall showed that high rainfall in the month preceding surveys significantly reduced butterfly abundance. Butterfly abundance and distribution did not differ between selectively logged and unlogged areas in either monthly or annual surveys and there was no difference between selectively logged and unlogged areas in the pattern of post-drought recovery. These results indicate that the abundance of R. makuta was significantly reduced both after high rainfall and during severe drought, but that these impacts were short-lived and were not affected by habitat disturbance. ENSO droughts on Borneo naturally often lead to widespread forest fires and thus impacts of ENSO events for butterflies are more likely to be due to indirect effects of habitat loss, rather than direct effects of drought on butterfly population dynamics.

Small-scale spatial association of the distribution for 55 abundant tree species with two environmental factors (humus depth and surface microtopography) was examined in two 1-ha plots of a heath (kerangas) forest in Central Kalimantan, Indonesia. More than 80% of the 55 species showed a significant habitat preference in humus depth and/or relative elevation in at least one plot. In particular, ten species occurring in both plots showed a consistent significant preference for humus depth or relative elevation in the two plots. Using randomization tests, however, only five species significantly associated with humus depth and no species with relative elevation. These results suggest that edaphic and topographic factors, especially humus depth, contribute to determining local spatial distribution and floristic composition of abundant tree species in the forest.

Relative densities of mahogany species vary across tropical Africa and correspond with changes in soil fertility and moisture status. Seedling growth of four co-occurring African mahoganies (Entandrophragma spp.) was studied in relation to soil nutrient and moisture status in a shade-house experiment. On naturally occurring forest soils, E. cylindricum and E. utile exhibited increased relative growth rate (RGR) and decreased root mass ratio (RMR) with an increase in soil fertility while E. angolense and E. candollei did not. Changes in leaf morphology with fertility did not correspond to changes in species performance. On moist, fertile soils, E. angolense outperformed congeners but E. candollei performed equally well on moist infertile soils. Entandrophragma cylindricum performed as well as E. angolense and E. candollei on two of three soil moisture stress treatments but E. utile consistently performed poorly. Comparative seedling performance fitted well with limited available data on the distribution of Entandrophragma spp. in relation to soil fertility and moisture gradients and suggests that within-forest microsite heterogeneity may help explain the distribution of Entandrophragma species within the Dzanga-Sangha Dense Forest Reserve, Central African Republic.

Estimates of insectivorous bat diversity in the Palaeotropics have largely been hampered by the lack of long-term studies employing appropriate capture techniques. Using a variety of trapping methods, 45 insectivorous bat species were captured in approximately 3 km2 of primary dipterocarp rain forest in Malaysia over 8 y. The cumulative site list for Kuala Lompat Research Station, Krau Wildlife Reserve, now stands at 51 insectivorous species. Although this is likely still not a complete list, it is already one of the most species-rich in the world. We attribute much of our success in recording this diversity to the extensive use of harp traps. Of the 45 species, 38 were captured in an intensive harp-trapping programme (> 1030 harp-trap nights) of the forest interior (22 species exclusively so). Insectivorous bats of the forest interior are thus a key component of Old World bat diversity, particularly in South-East Asia, and are dominated by taxa capable of detecting and capturing prey in cluttered environments (Hipposideridae, Rhinolophidae, Kerivoulinae and Murininae).

We conducted a survey of the epiphyte flora growing on the stilt palm Socratea exorrhiza in a primary lowland rain forest in Panama by means of a canopy crane. For each palm in a 0.9-ha plot, we determined diameter at breast height, tree height, per cent bryophyte cover and the number, identity and attachment site of all vascular epiphytes. The 118 palm trees hosted a total of 701 epiphytes and hemi-epiphytes, belonging to 66 species. Trees were estimated to be c. 20 y old before colonization with vascular epiphytes began. Epiphyte species were highly clumped and segregated along the vertical axis of the trunk. Sequential colonization led to an increased number of species and individuals as the tree grows. Epiphytes were associated with bryophyte patches much more than expected by chance, but no species seemed to depend upon them for establishment. The influence of tree size, age and bryophyte cover on the composition of the epiphyte community are discussed.

Ants are important agents of seed dispersal and they can play a fundamental role in the establishment and survival of plants (Beattie 1985). Leaf-cutting or fungus-growing ants (Myrmicinae: Attini) are dominant elements of the ant fauna throughout the neotropics. They collect different types of vegetative and reproductive plant material that serve as substrate for underground fungus gardens,which are the only food source for their larvae (Stradling 1991).

Vertebrate seed dispersers could impact the evolution of seed size or alter the pattern of seedling recruitment if they responded differently to seeds of varying size (Jordano 1995). For example, models of seed caching by birds and mammals predict that seeds of higher nutritive value should be placed farther from parent trees and in lower densities than lower quality seeds (Clarkson et al. 1986, Stapanian & Smith 1978, Tamura et al. 1999). Comparisons of seed removal rates among tropical tree species in South-East Asia (Blate et al. 1998) and Australia (Osunkoya 1994) failed to show a relationship between seed size and removal rate, although the probability that a seed was scatterhoarded by agoutis (Dasyprocta punctata) in a neotropical rain forest increased with interspecific seed size (Forget et al. 1998).

The Brazilian Atlantic Forest is one of the world's ‘hot spots’ for conservation because of its high level of endemism and number of endangered species (Myers et al. 2000). After centuries of deforestation, most of the remaining Atlantic Forest is scattered as small fragments on private land (Fonseca 1985, Jorge & Garcia 1997). Pollination could be impaired in these fragments because isolation often negatively influences the dispersal of insects, the most important pollinating agents in the tropics.

Data on the pollination biology of neotropical aroids are still scarce and concern only a few species (Beath 1999, Croat 1997, Gibernau et al. 1999, 2000; Mayo et al. 1997 and references cited therein). It appears from these studies that Anthurium, Monstera and Spathiphyllum are on the whole pollinated mainly by bees (but see Kraemer & Schmitt 1999), whereas Dieffenbachia, Homalomena, Syngonium, Philodendron and Xanthosoma are generally beetle-pollinated. Although araceous inflorescences may be visited by several insect taxa (Madison 1979), only a few are the legitimate pollinators for each species (Seres & Ramirez 1995, Valerio 1984, Young 1986).