Prey depletion is a major (but often neglected) factor driving the current decline of tigers (Panthera tigris L.) (Karanth & Stith 1999). Thus conservation planning for the tiger in a fragmented, human-dominated landscape requires reliable information on prey densities from various parts of its range. We report numerical and biomass density of six herbivores from the tropical dry-deciduous forests of Ranthambhore Tiger Reserve (RTR, 26°N and 76°E), Rajasthan, India, where these are important prey for tigers (Bagchi et al. 2003).

Terrestrial insectivorous birds in a cloud-forest on the north-western slope of the Peruvian Andes were described in terms of species richness, abundance, density, territory size and biomass. Abundance, density and territory size were also characterized for several understorey insectivores. The three terrestrial insectivore species, all in the genus Grallaria, had 35.25 territories on a 26.2-ha plot, defended territories of (mean ± SD) 1.65 ± 1.34 ha, dwelled at an average density of 4.4 ± 2.7 pairs per 10 ha per species and constituted a biomass of 2470 g per 10 ha. Eight understorey insectivore species had 122.75 territories on the plot, held territories 0.86 ± 0.62 ha in size, and lived at an average density of 5.0 ± 2.7 pairs per 10 ha per species. Six of the 11 species studied each occupied over 50% of the plot. Data on terrestrial insectivores from this study were compared with data from other Neotropical plots to examine how properties of guild structure relate to one another. Increasing densities, smaller territory sizes and higher biomasses appeared to be linked with decreasing species richness and increasing elevation, suggesting consistent patterns of covariance.

Lianas are woody climbing plants that begin their life cycles as seedlings rooted in the ground, but eventually rely on other plants for physical support in order to reach the top of the forest canopy (Holbrook & Putz 1996, Putz & Holbrook 1991). Lianas can negatively affect plants they climb by competing with them for common resources such as light, water and nutrients, and by causing them direct physical damage (Dillenburg et al. 1995, Pérez-Salicrup & Barker 2000, Stevens 1987, Whigham 1984). Yet, there is little documentation about the size at which liana individuals of different species begin to climb on other plants in nature. This information is important because the size at which a liana begins to climb on other plants will determine when lianas potentially start physically affecting their supporting plants. Furthermore, although the growth of liana seedlings might be determined by light (Sanches & Válio 2002), the availability of support will also largely influence the rate of growth of liana stems (Peñalosa 1982, 1983, 1985). Thus, information about the size at which liana species find support in the forest understorey will be useful in understanding future growth of liana individuals.

Fire is a common feature of tropical savannas and it has an important role in the ecology and evolution of the flora. Many woody species in tropical savannas are well adapted to fire and have a vigorous resprouting ability that enables them to survive recurring fire (Frost & Robertson 1987, Hoffmann & Solbrig 2003, Meyer et al. 2005). Studies on the interaction between fire and woody plants in Mediterranean-climate regions have considerably increased our understanding of the subject but relationships between plant attributes (stem diameter and height) and post-fire resprouting ability of southern African savanna woody species are poorly understood. Resprouting is a widespread mechanism by which many plants regenerate after partial or total defoliation (Bellingham & Sparrow 2000, Bond & Midgley 2001).

The breeding system of Laguncularia racemosa is variable among populations; some populations are androdioecious while other populations lack male plants. To determine whether androdioecy is widespread in L. racemosa, 65 populations were surveyed in Florida and the Bahamas. Fruits are water-dispersed, so the observed distribution of breeding systems was compared to local and regional water currents in order to determine whether dispersal could be important to the maintenance of male plants in androdioecious populations. Twenty-two of the 36 populations surveyed in Florida were androdioecious, with male frequencies that ranged from 1–68%. On the Florida east coast, all populations north of latitude 26°30′ N lacked males while all populations south of this latitude were androdioecious, which suggests that northern populations may lack males due to dispersal limitation. The pattern of distribution on the Florida west coast suggests that males may be maintained in some populations via dispersal. Nine islands in north-central Bahamas were surveyed, and androdioecious populations were found only on San Salvador Island, where male frequencies ranged from 5–28%. Dispersal, fragmentation, and selection hypotheses are suggested to explain the observed pattern of distribution; these hypotheses will be tested in future studies.

Monodominance in the tropics is often seen as an unusual phenomenon due to the normally high diversity in tropical rain forests. Here we studied Parashorea chinensis H. Wang (Dipterocarpaceae) in a seasonal tropical forest in south-west China, to elucidate the mechanisms behind its monodominance. Twenty-eight 20 × 20-m plots were established in monodominant and mixed forest in Xishuangbanna, Yunnan province. All individuals ≥1 cm stem diameter and 16 soil variables were measured. Parashorea chinensis forest had a significantly higher mean tree dbh compared with mixed forest. Diversity did not differ significantly between the two forest types. However, within monodominant patches, all diversity indices decreased with an increase in P. chinensis dominance. Floristic composition of P. chinensis forest did differ significantly from the mixed forest. These differences were associated with more fertile soils (significantly higher pH, Mn, K and lower carbon pools and C:N ratio) in the P. chinensis forest than the mixed forest. In contrast to current paradigms, this monodominant species is not associated with infertile, but with fertile soils. Parashorea chinensis seems to be especially associated with high manganese concentrations which it can tolerate, and with edaphic conditions (water, K) that allow this tall and exposed emergent species to maintain its water balance. This is in contrast with most previous studies on monodominance in the tropics that found either no effect of soil properties, or predict associations with nutrient-poor soils.

In January 1983, two 50 m × 50 m rain forest plots in the University of Ife campus in southwestern Nigeria were demarcated for a baseline study of species composition, litterfall and tree girth increments. By accident, a severe ground fire burnt one of the plots on 31 January, barely two weeks after litter traps had been set and species listing and first girth measurements completed.

The effect of this fire was assessed in the burnt plot after 14 months, in April 1984. The fire affected small trees especially, and there were indications that some species were more sensitive than others.

Manihot glaziovii, which was present in the plot and abundant in its vicinity before the fire showed a big increase in density after the fire because it was able to germinate in the openings created by the fire. These observations were related to succession, and it is concluded that the observation by some workers that the initial composition of a regrowth forest may be partly predicted from a knowledge of the seed bank in the soil may be applicable in the present case.

An estimated 154 million ha of tropical forest are cleared each year by human activities such as cattle ranching and agriculture (Whitmore 1997). When the economic return of these sites declines, they are often abandoned and allowed to regenerate. As a result, ‘secondary’ or ‘regenerating’ forests are becoming an increasingly common feature in tropical landscapes (Guariguata & Ostertag 2001). Unlike treefall gaps and other ‘naturally’ disturbed areas, the regeneration of secondary forests on anthropogenically disturbed lands does not always follow a predictable pathway (reviewed in Guariguata & Ostertag 2001). Instead, the type and intensity of post-clearing land use has major implications for the trajectory along which succession proceeds (Guariguata & Ostertag 2001, Mesquita et al. 2001, Uhl et al. 1988).

Because seasonality in tropical environments is driven by variation in rainfall, phytophagous tropical organisms are expected to exhibit mechanisms of escape in space and time that allow them to synchronize their breeding efforts with suitably wet periods of the year. This hypothesis was addressed by studying the breeding phenology of the nymphalid butterfly Hypolimnas bolina (L.) in the Australian wet-dry tropics. This species favours small, herbaceous larval foodplants that either die off annually or exhibit marked declines in leaf quality during the dry season. As expected, reproductive activity in H. bolina was broadly correlated with both rainfall and humidity, with individuals spending part of the dry season (early April to late August) sheltering in overwintering sites in a state of reproductive diapause. The timing of the overwintering period was similar between the 2 years, which suggests that individuals respond to seasonally predictable cues such as photoperiod. At least in 1998, the exit of butterflies from overwintering sites was relatively sudden and coincided with the first spring rainfall event. These findings suggest that H. bolina copes with seasonal adversity in the tropics by means of a regularly timed diapause.

The stomach contents of 683 fishes representing 39 species were examined to determine the diet of fish living in fast-flowing waters (rapids) of the Sinnamary River in French Guiana. Aquatic invertebrates were shown to be an important source of food in the rapids biotopes, in contrast to what has previously been observed for slow-flowing waters. Aquatic insects (e.g., the larval stages of Diptera, Ephemeroptera and Trichoptera) make up 55% of the diet of fish living in rapids. Such prey animals were more common in those biotopes than in slow-flowing waters. Twenty-two species of fish, each represented by at least 10 individuals in all samples, were analyzed for their stomach contents. The spectrum of prey items allowed for an estimation of the similarity of feeding habits. These diets were further compared to those inferred for other rivers of the Amazonian and Guianian regions.

Riparian forests (RF) provide shelter, feeding resources and commuting areas and are fundamental for local fauna during long drought periods in tropical dry forests. Nevertheless, information regarding vertebrate ecology in tropical RF is scarce. The studies of bats in riparian habitats have been mostly focused on insectivorous assemblages in non-tropical regions. We contrasted the occurrence of frugivorous bats between RF and upland dry forest (UDF) in a Neotropical dry forest region and evaluated how vegetation structure modulates frugivorous bat presence and abundance. We sampled bat ensembles and vegetation structure in three UDF and three RF sites in Jalisco, Mexico. Bat ensembles and populations were analysed with generalized linear models, including as independent factors: (1) habitat and (2) vegetation attributes. In 72 nights we captured 840 bats belonging to seven species. No effect of habitat type or vegetation structure on species richness was found, but habitat type did affect bat species composition and abundance. Moreover, vegetation structural traits affected frugivorous bat abundance. Frugivore abundance was higher in RF than in UDF probably because RF provides greater resources and more roosting sites. Riparian forests also present more canopy cover and accessible flight spaces. Our results support the importance of RF for frugivorous bats in terms of abundance and composition. Additionally, the lack of differences in species richness between UDF and RF highlights the importance of both habitats for maintaining frugivorous bats, as well as the related ecosystem processes and services in tropical dry forest landscapes.

The correlation between the biomass of forest primates and a chemical index of the average nutritional quality of leaves in tropical forests has been repeatedly documented since 1990. We tested the role played by protein : fibre on lemur biomass in a gallery forest in southern Madagascar. Plant species abundance was determined based on transect censuses. We calculated an average ratio of protein-to-fibre in leaves and an abundance-weighted ratio, i.e. the mean weighted by the basal area of tree species, to be compared with the figures available for other forest ecosystems in Madagascar and a number of anthropoid habitats. Lemur densities were evaluated through compilation of previous studies made from prior to 1975 and up until 2011 based on strip censuses and/or identification of all groups supplemented with new censuses. A high mean ratio of protein to fibre (> 0.4) supports high folivore biomass at 390 kg km−2 (reaching 630 kg km−2 in the closed-canopy forest area) compared with primate communities in other Malagasy forests (protein : fibre: < 0.5; folivore biomass: < 440 kg km−2), as predicted. However, the data corroborate the finding that the total biomass of lemur communities as well as the biomass of folivorous lemur species are low compared with those of African and Asian primate communities for a given protein : fibre ratio. Tree diversity and leaf production do not consistently explain this pattern. In contrast, the extinction of large folivorous lemurs during the past two millennia presumably allowed too little time for smaller-sized species to evolve equally effective morphological and physiological specializations for processing a large range of fibrous foods.

In New Caledonia, rain forests with an upper canopy dominated by single species of Nothofagus occur next to mixed-canopy forests, without discernible environmental cause. A potential explanation is that they are different successional stages. To test this hypothesis and predict long-term change in canopy dominance, population size structures of 61 canopy species were analysed in six Nothofagus-dominated forests and three adjacent mixed rain forests. Weibull analysis suggests that these Nothofagus forests are secondary forests, with recruitment insufficient to maintain monodominance, except at a high-altitude site. At low- to mid-altitudes the Nothofagus canopy is predicted to develop into a mixed canopy, unless moderate to severe disturbance occurs within its reproductive lifespan. However, adjacent mixed rain forests are also secondary, with 85% of analysed species showing no evidence of continuous regeneration. Fifteen species from both forest types showed reverse-J curves suggesting continuous regeneration, but only Calophyllum caledonicum did so consistently. Since few canopy species showed evidence of high shade tolerance and persistence, a small number of shade-tolerant species is predicted to dominate both forests in the long term, in the hypothetical absence of disturbance. Hence, temporal factors associated with disturbances play a key role in determining dominance in these forests.

The distribution of the arboreal ant community plus a termite species of the genus Nasutitermes was inventoried on 938 red mangrove, Rhizophora mangle L., trees in a completely flooded mangrove forest of the Sian Ka'an Biosphere Reserve, Quintana Roo, Mexico. Colonies sheltered in dry hollow branches of the trees and the pseudobulbs of the epiphytic orchid, Myrmecophila christinae. Two size classes of dry hollow tree branches were categorized in order to test differences in ant distribution. As some trees remained unoccupied by either an ant or a termite colony, we deduced that the competition for nesting sites was low. Differences in the composition of the ant community corresponded to the nature of the shelters (i.e. diameter of the hollow branches or orchid pseudobulbs). The ant fauna was richer in the large dry hollow branches of R. mangle than in the smaller ones, with certain ant species belonging to the subfamilies Ponerinae and Formicinae being significantly more frequent in the large dry hollow branches than in the small ones. Cephalotes and Pseudomyrmex were the most frequent ant genera inhabiting the dry branches of R. mangle, while Dolichoderus bispinosus was the most frequent ant species inhabiting the orchid pseudobulbs. Arboreal Nasutitermes sp. selected mostly the orchid pseudobulbs and thus indirectly interfered with ant nest-site selection. Our results highlight niche differentiation through the selection of nest sites among different types of shelter.

The family Echimyidae is one of the most widely distributed rodent families in the Neotropics. Virtually every tropical lowland forest contains at least one echimyid species, and many areas contain half a dozen or more species. The commonest terrestrial representatives of the family are within the genus Proechimys, and several species such as Proechimys semispinosus (Central American spiny rat) have been the subject of intensive ecological studies (e.g. Adler 1994, 1996; Adler & Beatty 1997, Alberico & Gonzalez 1993, Fleming 1971, Gliwicz 1984, Gonzalez-M. & Alberico 1993). P. semispinosus is often the most abundant rodent throughout its geographic range in Central America and northwestern South America, and its ecology is now fairly well-known.

Ecological and temporal factors can influence animal foraging patterns and may obscure our understanding of how native and exotic species interact. To understand how such factors affect foraging, the visitation of native and exotic bees and wasps was observed at nectar feeders within Mexican agroforestry systems, while documenting (1) vegetation management (low-shade vs. high-shade coffee), (2) light and floral resource levels and (3) recruiting ability, as measured by the change in visitation between two consecutive experimental days. On day one, Africanized honeybee visitation was significantly greater in low-shade habitats, and native solitary bee abundance was significantly greater in high-shade habitats, while native social bee and solitary wasp visitation were not significantly different between habitat types. After 24 h, Africanized honeybee visitation increased significantly in both habitat types, while native social bee visitation increased significantly only in high-shade coffee. In contrast, native solitary bee and native solitary wasp visitation decreased in both habitat types. Overall, this study reveals that Africanized honeybees exhibit only initial foraging preference for low-shade habitats, while native bees exhibit both initial and delayed recruitment-based foraging preferences for high-shade habitats.

Our aim was to evaluate the role of sucrose and the role of smell, taste and touch in the selection and consumption of fruit in wild spider monkeys. We recorded the feeding bouts of 14 adults for 9 mo in the Otoch Ma’ax Yetel Kooh Reserve, Punta Laguna, Yucatan, Mexico. For each of 2346 inspections on fruits of six species the consumption or rejection and the use of touch, smell and taste was recorded. Ten fruit samples (five ripe and five unripe) from each species were collected and the sucrose concentration was determined with a refractometer. As expected, sucrose concentrations were higher in ripe than unripe fruits. The difference in sucrose concentration between ripe and unripe fruits was positively associated with the proportion of inspections on ripe fruits and the proportion of consumed ripe fruits. Furthermore, the senses of touch and taste were used more often when fruits were ripe, whereas the sense of smell was used more often when fruits were unripe. The results suggest that sensory cues and sucrose concentration play important roles in fruit selection in spider monkeys.