(1) During 1978–1981, marked individuals of 107 species of treelets and shrubs in three forest types between 1300–1650 m elevation at Monteverde, Costa Rica, were monitored at monthly intervals for behaviour of leafing, flowering, and fruiting.

(2) Although there was not a pronounced seasonal pattern of leafing activity, more species produced new leaves in the dry season. Species that flush large quantities of new leaves do so more commonly in the drier months. Leaf loss was gradual and unobtrusive in species observed.

(3) Flowering activity was greatest in the late dry season and early wet season. Most species exhibited extended flowering; only 15% of the species were massively flowering. Massive flowerers showed less seasonality than extended flowerers.

(4) Of the species studied, the majority had relatively unspecialized flowers which were visited by a variety of insects; small bee-pollination was the next most common, followed by hummingbird, beetle, settling moth, sphingid, butterfly, large bee and fly pollination (the pollination system of 18 species was unknown). Hummingbird pollinated species showed little seasonality of flowering when compared with species exhibiting small moth, and beetle pollination syndromes, as well as those with unspecialized flowers.

(5) The vast majority of species studied have fleshy fruits (sarcochores). Fruiting activity was less markedly seasonal than flowering. Species with fruit are more numerous in the second half of the year (the wet season and early dry season). The second year of the study saw substantially fewer species in fruit than the first year; this is attributed to the greater than usual rainfall and inclement weather during the peak flowering season.

(6) Cloud forest shrub and treelet phenology is compared with patterns of other forests that have been studied. In general, the greater the rainfall, the less seasonality of flowering and fruiting is seen. Although Monteverde is very wet, rainfall is intermediate between that of lowland dry and lowland wet forest in Costa Rica. Seasonality of flowering and fruiting at Monteverde is more pronounced than at La Selva (wet) and less obvious than in Guanacaste (dry).

Although it is well known that riparian zones can contribute strongly to between-habitat beta diversity, for most taxa it is not clear how far this ‘zone’ extends, and whether it corresponds to easily recognizable topographic features. Forty 200-m2 plots were installed in a terra firme tropical forest to detect compositional variation in terrestrial herbs from the margins of small streams to the uplands. Plots were ordinated by their dissimilarity in species composition with non-metric multidimensional scaling. The riparian zone around streams was distinct in understorey herb composition from upland areas for about 100 m from the streams, or about 70 m asl in elevation, the exact distance depending on the size of the stream valley. However, the only assemblage that was almost completely distinct occurred as a narrow band a few metres wide along the streams. The rest of the riparian zone appears to represent an ecotone with continuous change, most of which occurs out to a distance of about half the width of the riparian zone as we defined it. Although riparian zones are legally protected in Brazil, they are frequently degraded. The complex factors leading to zonation around streams need to be understood to effectively manage these areas.

Tropical forests offer many more products than the category for which they are best known, viz. wood products. They can supply a host of raw materials, such as resins, oils, fibres and fruits, which collectively represent a commercial value far higher than is generally recognized. In addition they provide an exceptional abundance and variety of genetic resources, which make substantial contributions to modern agriculture, medicine, industry and energy. On top of these materials, tropical forests supply significant environmental benefits, such as protection of the soil and safeguards for watershed systems. While it is sometimes difficult to quantify the economic values of these diverse goods and services, they are often to be reckoned as equal to, if not higher than, the marketplace values represented by the commercial hardwood timber. Yet when the forests are exploited for their hardwood timber, the process is usually so disruptive to forest ecosystems that the other outputs are severely reduced. By contrast, one may exploit the forests for their other outputs with virtually no disruption to forest ecosystems. The paper describes the main categories of non-wood products available from tropical forests, analyses their relative worth, and offers summarized proposals for an expanded approach to forest development in order to take integrative account of the full range of forest benefits.

Leaf water and osmotic potentials and gas exchange were monitored during a prolonged El Niño drought in 1998 for saplings of seven species in a Bornean heath forest and compared with measurements taken during a subsequent wet period. The four dipterocarp species maintained reasonably good water status throughout the drought, especially Dipterocarpus borneensis which had thick and deep tap roots. In contrast, two of three non-dipterocarp species, Cleistanthus baramicus and Tristaniopsis obovata displayed predawn leaf water potentials approaching their turgor-loss points. During the drought, all species except D. borneensis displayed strongly reduced stomatal conductance after a brief exposure to sun, and all displayed lower maximum rates of stomatal conductance and net photosynthesis than during the wet period. Only Cotylelobium burckii displayed significant osmotic acclimation to the drought. T. obovata possessing a superficial root system suffered a high mortality due to the drought, but recovered faster after the first rains than the other species all of which had tap roots. Deep roots and strong stomatal control favour trees in tropical heath forests where water deficits probably occur regularly.

The food habits of four hypogeous Macrotermitinae species were studied using stable carbon isotope analysis in several biotopes of a humid savanna of West Africa (Lamto, Côte d'Ivoire). The proportion of woody and herbaceous material in the diet of the different species was determined by measuring the 13C natural abundance in the fungus comb. The diet varied with season and biotope, especially tree density. The results confirm the flexibility of the food habits of the fungus-growing termites as a consequence of their exosymbiosis with the fungus Termitomyces sp.

The distribution and formation of foraging trails have largely been neglected as factors explaining harvesting patterns of leaf-cutting ants. We applied fractal analysis, circular, and conventional statistics to published and newly recorded trail maps of seven Atta colonies focusing on three aspects: permanence, spatio-temporal plasticity and colony life stage. In the long term, trail patterns of young and mature Atta colonies revealed that foraging activities were focused on distinct, static sectors that made up only parts of their potentially available foraging range. Within these foraging sectors, trails were typically ephemeral and highly variable in space and time. These ephemeral trails were concentrated around permanent trunk trails in mature and around nest entrances in young colonies. Besides these similarities, the comparison of trail systems between the two life stages indicated that young colonies exploited fewer leaf sources, used smaller and less-complex systems of foraging trails, preferred different life forms as host plants, and switched hosts more often compared with mature colonies. Based on these analyses, we propose a general hypothesis which describes the foraging pattern in Atta as a result of initial foraging experiences, spatio-temporal distribution of suitable host plants, energetic constraints, and other factors such as seasonality and interspecific predation.

Trapping and netting of small mammals on a land-bridge island (Leyte) and on an oceanic island (Negros) revealed similar patterns of elevational change in abundance and species richness. Fruit bats (Pteropodidae) reached their greatest local densities in agricultural areas, and were least abundant in montane mossy forest. The fruit bats found to be common in agri-cultural areas are widespread in Southeast Asia: in contrast, species that were most common in forested areas are Philippine endemics. Fruit bat abundance was greater on the oceanic island than on the land-bridge island. Trappable small mammals (families Soricidae and Muridae) showed no change in species richness with increasing elevation, but did show a gradual increase in overall abundance. Even though the oceanic island was depauperate of non-volant mammal species, it had the higher abundance of non-volant mammal individuals; however, this may have been due primarily to differences associated with the elevation of sampling sites. Murid rodents at the higher elevations on Leyte tend to be those that are members of the old endemic group of Philippine murids, and those at lower elevations tend to be members of more recently arrived groups. Most non-volant small mammals at all elevations on the oceanic Negros, and in agri-cultural areas on Leyte, are non-native species.

Ants frequently interact with non-myrmecochorous diaspores on the ground in neotropical savannas. Our objective was to quantify the removal rate of these diaspores by ants and vertebrates in order to test the predator avoidance hypothesis, and to test how diaspore traits influence removal by ants and dispersal distance. We also investigated whether seed cleaning (removal of fruit matter simulating ant activity) can influence seed germination. We performed removal experiments with nine diaspore species in a reserve of cerrado savanna in south-east Brazil. Considerable differences in removal rates were found among the nine species. We found a positive linear relationship between lipid content and removal rates for five diaspore species. Vertebrate predation pressure was low for most species, limiting the benefits that ants can provide to plants to escape predators. Ants displace diaspores up to 25 m, which may increase the chance of a seed hitting a safe site. Smaller diaspores attain longer distances of dispersal than large ones. Seed cleaning increased the germination rate for five out of six species tested in greenhouse experiments. Ant activity can have relevant and possibly lasting effects on seed fate of plants adapted for vertebrate dispersal in the cerrado savanna.

Data on densities, biomass and ecological factors governing the distribution of various wild ungulate species in the difFerent management units of Gir forest from 1987 to 1989 were collected. Density of ungulates ranged from 50.8 km−2 to 0.42 km−2, the highest for chital (Axis axis), followed by chinkara (Gazella gazella), sambar (Cervus unicolor), nilgai (Boselaphus tragocamelus) and chowsingha (Tetracerus quadricornis). The density of chital did not vary significantly between different censuses and management units. The wild ungulate biomass ranged from 3290 kg km−2 in the National Park to 1900 kg km−2 in the Sanctuary East. Following the partial removal of people and livestock in the mid-1970s, there was an increase in the population of all wild ungulates except nilgai and wild pig (Sus scrofa). Concurrently, there was an increase in the proportion of wild ungulate prey in the lion's diet. Chital density has shown a 1320% increase. An increase in suitable habitats and a decrease in direct competition with livestock are the most likely factors to have triggered the eruption in chital population. These density estimates are discussed in relation to the prevailing ecological conditions in different management units of Gir.

Epiphytes are one of the most ubiquitous elements of tropical forest canopies, including seasonally dry tropical forests. Given the temporal variation in weather conditions in the latter, epiphyte populations may be subject to wide temporal variation in seedling recruitment, reproductive success, vegetative propagation and mortality rate. In this study, we use a 3-y demographic data set for Tillandsia brachycaulos to project its long-term population dynamics through the use of average and periodic matrices, as well as stochastic simulations. The results show that demographic behaviour varied over the 3 years of study, apparently in relation to rainfall. The first 2 years yielded a low λ value (0.79 and 0.80 – although only the former was significantly lower than unity), while the third year resulted in a λ = 1.08 (not significantly different from 1.0). When incorporating this demographic variation in an average matrix, a periodic matrix and stochastic simulations, the resulting overall λ was below unity in all three cases. The projections of the stochastic simulations suggest that the population would be able to persist in the long run only if the frequency of “good” years (defined here as those with an August rainfall above 200 mm) was above 0.6, which appears unlikely given that global warming might result in a lower frequency of rainy years in tropical dry forests.

Remnant trees in fields may facilitate regeneration in fallows by attracting seed dispersers and creating favourable sites for plant establishment. Ntumu shifting cultivators in Cameroon clearing rain forest spare some trees to provide shade for crops. This study examines their effects on regeneration by comparing vegetation in quadrats beneath and away from their crowns, in fallows of varying age (3-20 y). For fallows of all age classes, plant diversity was not significantly different between positions. Trees accounted for larger proportions of species and stems beneath remnant trees. Herbs, principally large monocots, accounted for larger proportions away from trees. Basal area was much higher in quadrats beneath trees. In all quadrats, the majority of individuals belonged to species with animal-dispersed seeds. These accounted for a larger proportion of individuals beneath trees (75%) than away (64%). Wind-dispersed species accounted for a larger proportion of stems away from trees (23.6%) than beneath (11.7%). These data suggest that enhanced seed rain by attraction of perching animals, demonstrated in a companion study, nfluenced regeneration patterns. Effects on regeneration were similar beneath trees of an animal-dispersed (Pycnanthus angolensis, Myristicaceae) and a wind-dispersed (Triplochiton scleroxylon, Sterculiaceae) species. Remnant trees in fallows may facilitate succession by nucleation, resulting in more rapid restoration of forest and conservation of nutrients in plant biomass.

Although undisturbed tropical evergreen forests are often thought to be fire- resistant ecosystems due to lack of sufficiently dry fuel loads (Bond & van Wilgen 1996, Kauffman et al. 1988, Uhl et al. 1988), this myth is rapidly collapsing with the proliferation of recent forest fires throughout south-east Asia (Kinnard & O'Brien 1998, Leighton & Wirawan 1986), Central America (Anon. 1998a), and northern South America (Anon. 1998b) following unusually severe seasonal droughts.

The effects of herbivory by the leaf-cutting ant Atta laevigata Fr. Smith on the re-establishment of forest trees in an abandoned farm near Manaus, central Amazonia, were investigated. Experimental seedling transplants and observations on seedlings which emerged naturally in the study area showed that damage by leaf-cutting ants negatively affected tree seedling survival and growth. However, excluding leaf-cutting ants from experimental plots for 20 mo did not significantly increase tree seedling densities. The number of seedlings emerging varied considerably between plots and this obscured any effect the ants may have had on seedling survivorship. Taller seedlings, and seedlings attacked only once, suffered less mortality than smaller seedlings and seedlings attacked twice or more. In general, mortality was greater for those species preferred by the ants, indicating that selective herbivory by leaf-cutting ants affects tree species composition. The number of seedlings attacked by A. laevigata remained approximately constant throughout the period of this study in spite of the fact that the number available for attack increased. Thus, the chance of any individual seedling being attacked declined with time, suggesting that the effect of Atta herbivory on tree establishment is stronger during the first few years of forest regeneration.

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.

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.

Determining the ubiquity of top-down control effects of predators on their prey and ecosystem processes is important for understanding community and ecosystem-level consequences that may result from predator loss. We conducted experiments at two spatial scales to investigate the effects of terrestrial frogs (Eleutherodactylus coqui) on aerial and litter invertebrates, plant growth and herbivory, and litter decomposition. At both scales, frogs reduced aerial invertebrates and leaf herbivory, but had no effect on litter invertebrates. At the smaller scale, frogs increased foliage production rates, measured as the number of new leaves and new leaf area produced, by 80% and decomposition rates by 20%. The influence of E. coqui on increasing primary productivity and decomposition rates at the smaller scale appeared to be a result of elimination and excretion rather than of controlling prey. While the results provide evidence for frogs controlling herbivorous prey at both scales, species effects on ecosystem processes were only detectable at the smaller scale. The results highlight the difficulties in conducting experiments at large spatial scales. The findings from this study imply that the loss of amphibians and other species of higher trophic levels may affect nutrient cycling rates in tropical forests.

We know surprisingly little about the fate of seeds of the Brazil nut tree (Bertholletia excelsa) under natural conditions. Here we investigate seed removal, predation and caching of Brazil nuts by scatter-hoarding rodents in the wet and dry seasons, based on an experimental approach using 900 thread-marked seeds. We tracked the fate of seeds handled by these animals to examine how seasonal food availability may influence caching rates, dispersal distances and cache longevity. Most seeds exposed to dispersal trials were removed by scatter-hoarders during the first week in both seasons and seeds were generally buried intact in single-seeded caches within 10 m of seed stations. Seeds were removed significantly faster and buried at greater distances during the dry season. The proportion of seeds buried intact was considerably higher in the wet season (74.4%) than in the dry season (38.2%). Most (99.4%) of the 881 primary caches monitored were recovered, but these had a significantly shorter lifetime in the dry season. Our results show that rodents are highly skilled at retrieving buried Brazil nuts and that caching behaviour appears to be affected by seasonal resource abundance. Reduced seed availability due to intensive harvest could potentially create a dry-season scenario where most seeds succumb to pre-dispersal predation, thereby adversely affecting the natural regeneration of Brazil nut trees.

The dispersal of African Acacia seeds in the presence and absence of large mammalian herbivores and ostriches was assessed in a savanna ecosystem in South Africa. In the absence of large herbivores, A. tortilis and A. nilotica pods were mainly dispersed in the shade, directly beneath the tree crown and seeds remained in pods for over 18 months. In the presence of large herbivores, A. tortilis, A. nilotica and A. karroo seeds were freed from pods and were dispersed into open, non-shaded habitats. Impala dispersed most A. tortilis seeds (18,900 ha−1), giraffe most A. nilotica seeds (1060 ha−1) and giraffe and kudu most A. karroo seeds (452 and 448 ha−1, respectively). Seedling survival in dung in open environments may exceed that of seedlings in soil shaded beneath the tree crown. It appears that seed dispersal by large herbivores may be advantageous to future seedling recruitment.

Soil-vegetation relationships were examined in a tabonuco forest community in eastern Puerto Rico using canonical correspondence analysis. Ca and pH were strongly correlated with the first ordination axis (r = 0.84 and 0.76, respectively), while Mg and Na were correlated with the second axis (r = 0.65 and 0.64, respectively); other soil variables were not significantly related to the first two axes. Four previously identified soil series corresponded well with the ordination, and statistically significant differences in soil variables were found among the soil series. Dominant canopy tree species Dacryodes excelsa and Manilkara bidentata were negatively associated with the first ordination axis and positively associated with dry soils having low concentrations of Ca and Mg and low pH. The palm Presloea montana was positively associated with the first axis and with wet soils having high concentrations of Ca and Mg and higher pH values. Another canopy species Sloanea bertenana was associated with the second ordination axis and with lower slope positions having higher concentrations of Mg.

The role of white-tailed rats (Uromys caudimaculatus) as dispersers of seeds of the Australian tropical rain forest tree Beilschmiedia bancroftii, (Lauraceae) was investigated by following the fates of seeds and seedlings over 2 y. Fruits of this tree are too large to be consumed by any avian frugivore except the southern cassowary (Casuarius casuarius), and the only other native mammal capable of dispersing the seeds is the musky rat kangaroo (Hypsiprimnodon moschatus). However, neither of these species has been documented to disperse the seeds of this tree. During a mast year, white-tailed rats cached seeds an average of 13 m from parent trees in a variety of microsites. Although none of the 61 cached seeds followed in this study survived to germination, comparison of seed, cache and seedling distributions suggested that most seedlings arose from rat-cached seeds. White-tailed rats cached seeds in both mast and non-mast years, but the time seeds remained on the forest floor and in caches was significantly shorter in non-mast years, suggesting that synchronous seed production increases the probability that some caches survive to germination. Because white-tailed rats are the most common and widespread native mammal capable of dispersing large-seeds, this study suggests that they may play an important role in the seed and seedling dynamics of large-seeded tree species in Australian tropical rain forests.