Understanding how wood decomposition varies spatially at the mesoscale (between 1-ha plots) may improve carbon flux estimates in Amazonian forests. An experiment was carried out to test the influence of soil, slope, above-ground tree live biomass (biomass), fine-litter mass and characteristics of neighbouring trees on the variation of wood decomposition between 1-ha plots in four species of tropical trees that vary in wood density (Manilkara huberi – 0.86 g cm−3, Couratari guianensis – 0.54 g cm−3, Hura crepitans – 0.32 g cm−3 and Parkia pendula – 0.29 g cm−3). A wood sample from each species (30 × 5 × 2.5 cm) was placed in each of 71 plots within 64 km2 of terra firme tropical moist forest in Reserva Florestal Adolpho Ducke. One year later, samples were collected and weighed. The effects of specificity of decomposers was measured by the association of decomposition with the wood density and with the taxonomic group of the nearest tree with dbh ≥30 cm. Wood decomposition was independent of soil (texture and nutrients), slope, biomass and fine-litter mass at the mesoscale, except for C. guianensis, which showed greater decomposition in locations with greater biomass. Decomposition was also independent of wood density and taxonomic group of nearby large trees. In general, none of the variables was useful as a predictor of wood decomposition at the scale larger than 1 ha. Thus, the use of models that include soil and topography to improve estimates of carbon flux are limited because wood decomposition does not follow similar mesoscale patterns to that of biomass and fine-litter decomposition. Also, the results indicate that wood decomposition is more likely to be associated with generalist decomposers than with specialists associated with neighbouring trees.

To better understand the role of seed banks in ecological succession of dry forests, we compared similarities between vegetation and seed banks and assessed the relative contributions of seed dispersal and persistence in chronosequences in the Brazilian semi-arid region. To sample the standing vegetation and the seed bank, we collected data in three sites with three successional ages in each one (5 y, 25 y and 45 y). A total of 180 soil samples (three sites × three successional ages × 10 plots × two components) were collected. The composition of the seed bank was assessed by the seedling emergence method. Of 166 species identified in the standing vegetation, only 50 (30.1%) were also present in the seed bank, resulting in low similarity (Jaccard index = 0.02–0.21) and reflecting the rarity of woody species and the dominance of annuals (71% of richness). The relative importance of seed persistence and seed dispersal to seed banks composition were balanced in most cases (difference was not rejected in four out six comparisons). Those results suggest that seed banks in tropical dry forests are largely the result of high dispersal rates and the persistence of allochthonous annual species that contribute to decoupling seed bank and vegetation composition.

We investigated the pollinator assemblage in Myristica dactyloides, a dioecious tree species occupying the intermediate canopy stratum of the mid- and high-elevation wet evergreen forests and endemic to Sri Lanka and the Western Ghats of India. We surveyed two populations and, in one of them, marked four male and three female trees for observations on floral display and insect foraging, and two female trees for experimental pollination. Yellow sticky traps were used to sample insects in the canopy during the flowering season of December 2007 in addition to direct observations of insect activity in 2006. Myristicaceae members from other tropical areas have been reported to be specialized to beetle pollination, but our observations provide evidence of a generalist pollination system in M. dactyloides, composed of small, diverse insects: thysanopterans (thrips), coleopterans (beetles), halictid bees and dipterans (syrphid and phorid flies). Quantifying floral display, we found that female inflorescences were smaller, offered no reward and attracted significantly fewer pollinators in comparison to male inflorescences. Fruit set was low and could be attributed to a 29% flower abscission and abortion of young fruits, but a reasonably high natural pollination efficiency combined with pollination experiments established that there was no pollination limitation in the study population.

The present study aims to investigate the effects of vegetation structure (plant abundance and height) and soil characteristics (soil organic matter and macronutrients) on insect gall richness, and determine the extent to which these effects are mediated by the indirect effects of plant species richness. The study was performed in forty-nine 100-m2 savanna plots in Parque Nacional das Emas (Brazil) and sampled a total of 985 individual plants of 71 plant species and 97 insect gall morphotypes. Cecidomyiidae (Diptera) induced the most insect galls (38.1%), and the plant family Myrtaceae had the greatest richness of insect gall morphotypes (16). Path analysis of plant abundance, plant height, soil macronutrients, soil organic matter and plant species richness explained 73% of insect gall richness. The results show that soil macronutrient quantity has a direct positive effect on insect gall richness, whereas plant abundance and plant height had only indirect positive effects on insect gall richness via the increase in plant species richness. These findings showed that both plant-related and environment-related factors are important to induce insect gall richness in Neotropical savannas, and that plant species richness should be taken into account to determine the richness of insect galls.

Human pressure on forest resources in southern Benin has led to a dramatic reduction and disturbance of natural forest patches. The largest remaining forest reserve in southern Benin is the Lama forest, which is known to be a reserve for many endangered species and situated in the boundary between dry forest and savanna. From cluster analysis and hierarchical classification of tree species composition, five forest types were identified in the Lama forest, and ordination techniques were used to determine to what extent these forest types were associated with physiognomic tree characteristics. The geographical position of vegetation plots was used to examine the spatial distribution of the identified forest types. The forest types were interpreted as levels in a successional sequence ranging from either disturbed forest or formerly cultivated farmland to dense forest. Based on the outlined succession sequence it was suggested that reforestation should focus on establishment of Anogeissus leiocarpus, Albizia zygia, Lannea nigritana, Ficus exasperata and Lonchocarpus sericeus as these tree species are associated with the initial forest types.

Most of the forests of the Amazon basin grow on nutrient-poor soils (Jordan 1982). Despite this, these forests remain productive through a variety of nutrient conservation mechanisms and a very effective system of organic matter decomposition and nutrient cycling (Jordan 1982). When an area of forest is fragmented however, the remaining patches experience modified microclimatic conditions (Camargo & Kapos 1995, Didham & Lawton 1999), and changes in floristic composition (Laurance et al. 1998), which can affect the decomposer community (Didham et al. 1996, Souza & Brown 1994) and consequently the decomposition process.

Associational resistance occurs when host plants experience reduced attack when in the presence of other plant species (Atsatt & O'Dowd 1976, Tahvanainen & Root 1972). The issue is most studied in agriculture and forestry because of the potential benefits to pest control (Andow 1991, Brown & Ewel 1987, Tahvanainen & Root 1972), but recent research indicates that associational resistance may be relatively common in natural systems as well (Hjältén et al. 1993, Karban 2007, Vehviläinen et al. 2007, Wise et al. 2009; but see Östergård & Ehrlén 2005, White & Whitham 2000), especially against specialist herbivores (Hambäck et al. 2000, 2003; Stenberg et al. 2007).

Hemi-epiphytic figs (Moraceae; Ficus subgenus Urostigma) are a distinctive component of the canopy of tropical rain forests. The hemi-epiphytic habit has risen independently several times, and is recorded in over 20 plant families today, but with approximately 350 species globally figs are by far the most important (Berg & Corner 2005, Putz & Holbrook 1986). They are ubiquitously diverse in tropical lowland rain forests and are represented by independent radiations in each region (Harrison 2005, Jousselin et al. 2003). Moreover, their abundant production of fruit at all times of the year makes them functionally important as food for wildlife, especially during periods of general fruit shortage (Shanahan et al. 2001a). However, hemi-epiphytic fig populations occur at very low densities and this, combined with the difficulties of access to the canopy, has meant that study of their biology lags behind that of other rain forest plants (Harrison et al. 2003). Here, I present the first estimates of mortality and recruitment for any community of hemi-epiphytic figs.

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.

The breeding season and diet of the rat Arvicanthis was monitored from December 1983 to November 1985 in the semi-arid Sudan savanna at Kano, Nigeria, West Africa. Breeding began 1–2 months before the start of the rainy season and ceased at the beginning of the dry season. The diet of Arvicanthis was omnivorous, but with seasonal differences. Monocotyledons and dicotyledons predominated in the diet in the dry season, with seeds and insects increasing in the diet in the rainy season. The major differences between the ecology of Arvicanthis at Kano and on the East African savanna were that in East Africa the breeding season is longer and begins after the start of the rainy season. These and other dissimilarities between the biology of Arvicanthis in the two areas could be due to the effect of climatic differences on food supply and to the possible existence of different taxonomic groupings of Arvicanthis in the two regions.

Nest site selection is critical for social insects since poor choices can heighten predation risks and result in reproductive failure (Franks et al. 2002). Social bees vary in their nest site requirements and among the Apis bees in South Asia, Apis dorsata and A. florea nest in open combs, whereas Apis cerana nests in cavities (Crane 1999). Apis dorsata often nests in aggregations, and the large open nests can be about 1.5 m wide and are located in sites such as cliff faces or on the underside of branches of tall trees that are inaccessible to most predators except skilled fliers and climbers (Crane 1999, Seeley et al. 1982). Apis dorsata, which is widely distributed in tropical and subtropical Asia, is an important source of honey and wax for local communities, and understanding its nesting biology would help in the management and conservation of this economically important species.

Habitat fragmentation is a major cause of biodiversity loss in agricultural landscapes. Studying habitat connectivity in fragmented landscapes is therefore pivotal for better understanding the factors that shape faunal communities in anthropogenic landscapes. Amphibians have limited dispersal abilities, strong site fidelity and often perform seasonal movements to reach relatively distant breeding habitats. This calls for a better knowledge of which landscape features might promote dispersal, especially in crops. We applied graph-theoretic network analyses to a set of 35 waterbodies embedded in 10 rice fields in a savanna–rain forest ecotone, Tocantins, Brazil, to assess the importance of landscape features (forest patches, waterbodies) for anuran functional connectivity within the entire network. We used taxonomic, functional and phylogenetic diversity as proxies of anuran functional connectivity (i.e. dispersal ability intrinsic to the taxa), based on previous associations uncovered between species diversity metrics and landscape connectivity. We found that, assuming individuals belonging to each of the 14 amphibian species recorded are unable to disperse over 800 m, forest and waterbody area and abundance are the most important predictors of waterbody importance for connectivity. Hence, pond network connectivity for amphibians in rice crops depends on (1) abundant and large forest patches in the area surrounding waterbodies, and (2) a network of abundant waterbodies.

A greater relative allocation of phosphorus (P) to photosynthetically active cells functions to maintain a rapid photosynthesis under P limitation, and may be a key mechanism of plants to use P efficiently. This mechanism has not been studied in tropical trees despite the productivity of tropical forests often being limited by P. In this study, the spatial distribution of P among tissues on a cross-section of leaf lamina was analysed for 13 tree species from P-limited sites on Mount Kinabalu, Borneo. Most species showed greater P concentration in palisade mesophyll than in spongy mesophyll and epidermal tissues, suggesting that tropical trees under P limitation localize foliar P in photosynthetic palisade mesophyll.

The El Niño-Southern Oscillation (ENSO) phenomenon occurs irregularly and supra-annually at intervals of 2–7 y (Hughen et al. 1999, McPhaden et al. 2006), and is the strongest source of supra-annual climate fluctuation (Hughen et al. 1999, Philander 1990). During ENSO, the interior of the South-East Asian tropics, which is characterized by constant high temperature and no distinct dry season, experiences severe drought (Walsh 1996).

Phenological patterns of flowering and fruit-set were studied in cocoa trees (Theobroma cacao) (Sterculiaceae) at monthly intervals in two contrasting habitats in Costa Rica for a one-year period. One of these habitats, a well-maintained plantation, had irregular and broken shade cover {Erythrina trees in particular) while in the other habitat, a ‘cocoa forest’, cocoa trees were heavily shaded by Huara crepitans (Euphorbiaceae). ‘Matina’ variety cocoa trees of about the same age (50–60 years) were censused in both habitats. Cocoa-pollinating midge (Diptera: Ceratopogonidae and Cecidomyiidae) availability was estimated by sampling immature stages in experimentally-distributed ground-cover breeding substrates, comparing overall abundances and species numbers between the two habitats over three census dates (dry, mid-rainy, and late-rainy seasons), along with examination of fungal-rotted (diseased) cocoa pods both on trees and the ground.

Although total flower production was much greater in the plantation habitat, total production of new pods was similar between habitats. Flowering followed a cyclic temporal pattern in the forest but not in the plantation. Sudden leaf drop of forest shade trees in the dry season probably triggered a cyclic response in which flowering peaked in the first half of the rainy season.

There was an inverse relation for frequencies of mature cocoa pods killed by squirrels and pathogenic fungi (Monilia roreri and Phytophthora) between the two habitats: squirrel-killed pods were far more abundant in the plantation than in the forest, and the opposite for fungus-killed pods. Fungus-killed but otherwise intact pods, and not squirrel-killed pods rotting on trees, were a major breeding site for midges, particularly during the late rainy season. Ceratopogonidae were most abundant in the dry season and frequently encountered in cocoa pod husks and banana tree trunk sections in both habitats, and much more so in the forest habitat. The abandoned cocoa plantation (cocoa forest) supported a more diverse assemblage of pollinating midges than the plantation.

In the plantation but not in the forest, a negative correlation was discovered between distance from shade trees and the numbers of pods on trees, suggesting greater pollinating activity by midges in cocoa trees beneath shade trees than away from them. The uniform dense shade cover in the adjacent forest probably obliterated such a pattern.

In neotropical forests many species of plant depend on animals for pollination and seed dispersal and it has been well documented that bats play an essential role in dispersal of many flowering plants (Gardner 1977). Bats are responsible for colonization of plants into forest gaps because they often disperse the seeds of plants adapted for growth in disturbed areas. Species of Cecropia, Piper, Solanum and Vismia are especially important pioneer plants, and bats play a critical role in the dispersal of these secondary woody species into both secondary and primary forests, and into the seed bank (de Foresta et al. 1984, Lobova et al. 2003).

The germination response of Uraria picta to five environmental factors was investigated. It germinated both in light and dark but germination in the light was significantly better than in the dark; there was further germination when seeds first placed in the dark were later brought into the light. It germinated well in the three soil types used but germination in humus and sand was significantly better than in red earth. There was an increase in germination with an increase in burial up to 1.5 cm, thereafter germination levelled off. There was no germination in water-logged conditions and there was an increase in germination as soil moisture decreased. Alternating temperatures of 31/21°C and 31/15°C favoured germination while 21/15°C inhibited germination. The results are discussed in relation to the phenology and distribution of the species.