Past studies of large, infrequent wind disturbances have shown that topographical, biological and meteorological factors interact to create complex damage patterns to forest ecosystems. However, the extent to which some of these factors change the forest microclimate along a vertical forest profile is poorly known. In a previous study, we correlated tree damage with a hurricane model that estimated past hurricane impacts within Cusuco National Park, Honduras over a 15-y period. Here we use the model to compare physical tree damage among different species in ten 150 ×150-m plots and to correlate modelled exposure of hurricanes to microclimate measurements along the vertical canopy over a 12-mo period. It was found that past hurricane impacts could still be detected long after the events. Different tree species showed different levels of wind damage. Most branch damage was observed on conifers (Pinus spp.), followed by angiosperm species. Vapour pressure deficit increased with height in the canopy and with increased disturbance level. A linear model explained 83% of the total variance in vapour pressure deficit, with 67% attributed to monthly fluctuation, 15% to altitude, 12% to historical hurricane damage and 6% to height in the canopy.

Responses of plants to herbivory are dependent on the type of damage and the ontogenetic stage of the plant. We compared the effects of stem pruning and defoliation on seedlings of Colophospermum mopane, an ecologically important tree species widely distributed in southern Africa. The growth of 160 greenhouse-grown juveniles were measured for 6-mo after germination and then 6-mo after treatments including 50% defoliation, 100% defoliation, 50% stem pruning and controls. Pruning resulted in 30% reductions in total leaf area, height and biomass. Partial defoliation resulted in 30% reductions in total leaf area and plant biomass. However, complete defoliation resulted in a 30% increase in biomass production, a doubling in leaf and lateral branch number, a 45% reduction in leaf size, and no change in total leaf area. Thus, completely defoliated seedlings showed greater performance than those that were only partially defoliated, indicating that C. mopane has become adapted to the chronic and severe defoliation inflicted by Imbrasia belina caterpillars. Comparison of our results with other studies indicates that C. mopane seedlings are less herbivory-tolerant than adults and that pruning has more negative effects than defoliation. Thus, seedling browsers may constrain recruitment in C. mopane, influencing its population dynamics and abundance.

We compared reproductive characteristics of the dendrobatid frog Colostethus trinitatis at the Tamana cave in the Central Range hills and at five forest stream sites in the Northern Range hills of Trinidad. There were significant differences between sites in adult female body size, intraovarian clutch size (in absolute terms and relative to body size) and the size of tadpoles carried by male frogs. Clutch sizes ranged from 6 to 13 in the Northern Range samples and from 12 to 26 at Tamana. Adult male body size was similar at all sites. Tadpoles carried by male C. trinitatis at Tamana were significantly smaller (mean length 14.2 mm) than those carried by males at the five Northern range sites (mean length 16.4–16.7 mm). The smallest clutches and largest tadpoles were found at Mount St Benedict, where there was evidence of size-selective predation on tadpoles by fish. Tamana, where clutches were large and tadpoles small, differed from the Northern Range sites in terms of the physical environment (cave vs forest) and the abundance of invertebrates. We discuss possible ultimate and proximate causes of the differences in clutch size and tadpole size, particularly size-selective predation and availability of food.

The rates of water loss and humidity preference of carabids from dry tropical habitats have been studied and compared with corresponding data from temperate carabids and tropical tenebrionids. Within each group of beetles the rate of relative water loss decreases with increasing body size. Carabids from dry tropical areas have rates of water loss which are lower than those of temperate species, but considerably higher than the values for tenebrionids from dry tropical habitats. Small temperate carabids can stay in dry air for only a few hours, whereas large tropical tenebrionids may survive for weeks without becoming critically dehydrated. Given the choice between a dry and a humid atmosphere, well hydrated beetles of all groups will initially choose the dry atmosphere. Most temperate carabids will switch to humid atmosphere after a few hours and tropical carabids after 1–3 days, whereas tropical tenebrionids may remain in dry air for almost 3 weeks. The temperate carabids are very sensitive to dehydration and will shift to a humid atmosphere when dehydrated by only 2–5%. Tropical carabids and tenebrionids will shift first when they are dehydrated by 7–20% of their body weight in a hydrated state, implying that these beetles are considerably less sensitive to water loss than temperate carabids.

Isolated pioneer trees have been shown to increase the deposition of animal-dispersed seeds. The effect of gender on seed rain has not yet been investigated, and this study aimed to evaluate whether female and male plants of a pioneer dioecious zoochoric tree differ with respect to the seed rain under their canopies. Seed rain was evaluated for 13 mo, from October 2009 to October 2010, in secondary vegetation of the Atlantic forest in southern Brazil. We used 60 seed traps (0.5 m2): 40 traps under the crowns of 40 Myrsine coriacea (Primulaceae) trees (20 male and 20 female individuals) and 20 at sites without trees. We found 365071 diaspores belonging to 115 morphospecies from 37 families, and 38.3% of the morphospecies were trees, most of them zoochoric. The female trees accumulated a greater number of diaspores and species richness than male trees. The male trees accumulated a higher number of seeds and species than areas without trees. This study shows that sites containing female and male trees of M. coriacea and sites without trees differed significantly in terms of seed rain, and there is a gender effect in this dioecious, pioneer tree species because female plants promote an increase in the richness and abundance of diaspores.

Odontomachus chelifer ants collect fallen arillate seeds of Cabralea canjerana (Meliaceae), a bird-dispersed tree of the Atlantic rain forest. In the nest the larvae are fed with the lipid-rich aril, and the viable seed is discarded. Benefits from secondary seed dispersal by ants are well documented for tropical plants, but benefits to ants from consuming vertebrate-dispersed diaspores are uncertain. Twelve captive colonies of O. chelifer were used to investigate the effect of aril consumption on larval development. Treatment colonies were supplemented with 1 g of C. canjerana arils, whereas control colonies were supplemented with 1 g of synthetic diet. Egg and larval production did not differ between experimental colonies after 5 mo. Aril-fed larvae, however, grew 3.5 times larger than those in control colonies. Essential fatty acids in the arils possibly account for improved larval development. Consumption of lipid-rich arils may be critical under scarcity of arthropod prey. Improved larval development through aril consumption confirms that this ant-seed interaction is facultatively mutualistic. This result is meaningful given the predominantly carnivorous diet of O. chelifer, and the generalized nature of ant-seed/fruit interactions in tropical forests. Whether or not benefits to larvae translate into significant gains for ant colonies is uncertain.

Many tropical mammals reproduce seasonally, although the circum-equatorial climate is more stable and less seasonal than that of temperate zones. The mechanisms underlying seasonal reproduction in the tropics remain enigmatic. Female reproduction and its relation to environmental factors were investigated in the Neotropical bat species Saccopteryx bilineata. Colonies consist of year-round stable groups of several females that are defended each by an adult male. Females give birth to a single offspring each year and it is suggested that mating is restricted to November and December. In this study, it was asked whether females of a Costa Rican colony come into oestrus around the same time each year and whether oestrus times are synchronized. Oestrogen and progesterone metabolites were monitored from faeces between October and January in four years. Oestrus was identified in 32 females. In addition, climatic factors such as rainfall and temperature were monitored at the study site. Results indicate that (1) females exhibit monoestry, (2) oestrus dates cluster around the first half of December, (3) reproduction is strongly seasonal and highly predictable and (4) oestrus times are possibly influenced by long-term cues like photoperiod and short-term cues like sudden changes in rainfall and temperature.

The high predation pressure in aquatic environments is generally assumed to be the ultimate cause of terrestrial breeding in anurans (Downie 1993, Magnusson & Hero 1991, Poynton 1964, Yorke 1983). It has evolved multiple times and is presently found in most anuran families (Bogart 1981, Duellman 1992). It is often associated with higher humidity and thus lower desiccation risk in tropical forests (Duellman & Trueb 1986). Most clutches that are oviposited terrestrially are either hidden in subterranean refuges or attached more or less exposed to vegetation (Duellman & Trueb 1986, Lamotte & Lescure 1977). Exposed clutches however, face the risk of desiccation, even in rain-forest environments (Rödel pers. obs.) and are still vulnerable to predation. Such disparate groups as various arthropods (Villa 1977, 1980; Villa & Townsend 1983, Vonesh 2000), frogs (Crump 1974), snakes (Roberts 1994, Scott & Starrett 1974, Warkentin 1995) and birds (Brosset 1967), have been reported to feed on these clutches. The foam nests,which occur in at least six tropical anuran families, seem to provide better protection. Their drying surface and their more or less liquid interior offers the tadpoles an aquatic environment that is well protected against desiccation and predation (Duellman & Trueb 1986, Seymour & Loveridge 1994). In addition the bubbles of the foam facilitate oxygen diffusion within the nest and may even provide a capacious oxygen store for eggs and hatched tadpoles (Seymour & Loveridge 1994). Few predators have been reported to feed on foam nests, one of which,paradoxically, is a frog (Drewes & Altig 1996). In the Taï National Park, Ivory Coast, we discovered a quite unexpected group of predators preying on foam nests and frog clutches exposed on leaves: monkeys.

Ecological and evolutionary factors influence the presence of modules in species interaction networks, and these modules usually cluster functional similar species. But whether closely related species form modules is still unknown. We tested whether the interaction networks formed by frugivorous birds and Miconia plants are modular and evaluated how modules were divided. To do so, we gathered from the literature data concerning four networks of Miconia and their frugivorous birds (three from Brazilian savanna and one from a rain forest in Panama). We quantified modularity using binary and weighted algorithms and also tested the relationship between bird traits (body mass, dietary specialization, migratory behaviour and phylogeny) in relation to within- and among-module connectivity indices (c and z values). If considering only binary information, networks did not present distinct modular structure. Nevertheless, by including interaction strength, modules can be detected in all four Miconia-bird networks. None of the bird traits, however, was related with the connectivity indices. The possible fluctuation of frugivorous bird abundance coupled with the asynchronic fruiting period of Miconia might favour the formation of temporal modules comprising birds and plant species with phenological overlap, ensuring seed dispersal and facilitating the coexistence in sympatry. Bird traits had little effect on the role that each species plays within the modular network, probably because the frugivorous assemblages were dominated by small-bodied and opportunistic species.

Plant–animal mutualistic interactions through ecological network systems and the environmental conditions in which they occur, allow us to understand patterns of species composition and the structure and dynamics of communities. We evaluated whether flower morphologies with different pollination syndromes (ornithophilous and non-ornithophilous) are used by hummingbirds and whether these characteristics affect the structure (core-peripheral species) of hummingbird networks. Observations were made in flowering patches, where plant–hummingbird interactions were recorded at three altitudes (300–2500 m) during three seasons (dry, rainy and post-rainy) from 2015 to 2016 at El Triunfo Biosphere Reserve, Chiapas, Mexico. We recorded 15 hummingbird species interacting with 58 plant species, and the greatest number of interacting hummingbird species (11; 14) and plant species (28; 40) were found at middle altitudes and during the dry season, respectively. In all study sites, most of the plant species visited by hummingbirds had an ornithophilous syndrome (67%) at high altitudes (22 plant species) and during the dry season (26 plant species), but more individual hummingbirds visited non-ornithophilous plant species. The hummingbird species at high altitudes exhibited the greatest level of specialization towards plants (H2′ = 0.74), but the networks of plant-hummingbird interactions were generalist (H2′ = 0.25); i.e. visiting plants with both syndromes, at low altitudes. The core generalist hummingbird species remained constant with altitude and season, but the core generalist plant species varied between different altitudes and seasons according to the phenology of the species.

Lizards of the genus Anolis have been widely studied, however, little is known about the effects of environmental seasonality, food availability and geographic isolation on body condition, growth rate and habitat use of lizards. The existence of an insular and a continental population of Anolis nebulosus (clouded anole), separated by only 0.47 km, represents an ideal opportunity to address this topic. We compared seasonal fluctuations in food availability (arthropod density) for anoles, as well as body condition, growth rate and habitat use in the two populations. Food availability throughout the year was sampled every 2 mo by trapping arthropods at each site. Lizards were also monitored and measured every 2 mo by surveying three quadrats in each site over 2 y giving a total of 30 visits for each quadrat. Results suggested that composition and density of food supply was similar for the two populations. Nevertheless, food supply responded to seasonality of rainfall, with an increase of 1.5 times during the rainy season. Despite similarity in food availability, insular anoles had body condition that was 5–10 times better, with growth rate twice as fast, and used similar perches. The role of predation, and inter- and intraspecific competition are discussed as possible drivers.

Tubificid worms that live in the paddy mud increase in numbers when an organic fertilizer is applied. They mix the soil by passing it through their gut as well as by their burrowing and respiratory movements, thereby checking the sprouting of paddy weeds. Tubificids inhabiting the pond's mud also serve as fish food. It is suggested that such a pond might be appropriate for aquaculture.

This study considers a method to control paddy field ecosystems based on the above to produce rice and freshwater fish, with organic fertilizers but without the use of herbicides and insecticides.

All woody growth was enumerated in three transects, each 960 m x 20 m, in derived savanna in the Olokemeji Forest Reserve in south-west Nigeria. The data for species density, species basal area and stem girth classes were analysed by nested-block analysis of variance and covariance. The use of ‘total covariance’, the sum of all covariances at a block size, contributes to understanding of the pattern present.

Three scales of pattern were evident. Patchiness at 160–320 m is interpreted as a response to soil differences or to the pattern of previous farming, which may itself have been determined by soil differences. Patchiness at 20–40 m is attributable to varying intensity of burning. At the smallest scale, of 10 m, there is evidence of regularity of distribution resulting from interference between individuals, possibly due to competition for water.

In 1999, Dalling & Harms simulated 100% above-ground herbivory on seedlings of Gustavia superba, a large-seeded species from Barro Colorado Island, Panama, and showed the remarkable ability for cotyledons to regenerate up to eight new shoots. They used this evidence to propose that cotyledon size (at least in this species)was adaptive in surviving pre- and early post-germination hazards (Dalling & Harms 1999). In this note we describe the first record of multiple resprouting in an Australian tropical plant species. Idiospermum australiense (Diels) S. T. Blake (Calycanthaceae) exhibits characteristics similar (but not identical) to G. superba that support the contention of Dalling & Harms (1999).

Tropical forest insects are vertically stratified between the canopy and understorey. Using 60 traps set at two heights above the forest floor (30 at 15 cm and 30 at 1 m) we compared abundances in capture height, persistence in traps, and sex of three co-occurring understorey butterflies (Cithaerias pireta, Dulcedo polita and Pierella helvina) in Costa Rica. We captured, marked and released 283 individual butterflies (65 C. pireta, 79 D. polita, 139 P. helvina) and showed all three species were captured more often in low traps, and P. helvina was captured only in low traps. The probability of remaining in traps for 24 h did not differ significantly for D. polita and P. helvina, but was significantly lower for C. pireta. The odds of trapping either sex did not differ significantly for P. helvina and C. pireta, but they were significantly lower for D. polita males. We experimentally demonstrate that these co-occurring species fly and feed just above the forest floor, but differ with respect to their persistence in traps and attraction to traps by sex. Our study implies that closely related species can exhibit behavioural differences that may influence population abundance estimates in multi-species studies.

IPCC predictions for Honduras indicate that temperature will increase by up to 3–6°C and precipitation will decrease by up to 7–13% by the year 2050. To better understand how fern and lycophyte communities might be affected by climate change, we comprehensively surveyed the community compositions of ferns and lycophytes at Celaque National Park, the highest mountain in Honduras. We surveyed a total of 80 20 × 20 m2 plots along an altitudinal gradient of 1249–2844 m a.s.l., identifying all species and estimating their abundances. We recorded a total of 11,098 individuals from 160 species and 61 genera. Community composition was strongly influenced by changes in altitude, precipitation and the abundance of bryophytes (a proxy for air humidity). Of the 160 species, 63 are expected, under a RCP2.6 scenario for the year 2050, to shift their range fully or partially above the maximum altitude of the mountain. Of these, 65.1% are epiphytes. We found that species with narrow altitudinal ranges at high altitudes were more at risk. Our study indicated that conservation efforts should prioritise higher altitudinal sites, focusing particularly on preserving the vulnerable epiphytic fern species, which are likely to be at greater risk.

Theoretical models predict that plant interactions with free-living soil microbes, pathogens and fungal symbionts are regulated by nutrient availability. Working along a steep natural gradient of soil fertility in a Costa Rican tropical dry forest, we examined how soil nutrients affect plant–microbe interactions using two complementary approaches. First, we measured mycorrhizal colonization of roots and soil P availability in 18 permanent plots spanning the soil fertility gradient. We measured root production, root colonization by mycorrhizal fungi, phosphatase activity and Bray P in each of 144 soil cores. Next, in a full-factorial manipulation of soil type and microbial community origin, tree seedlings of Albizia guachapele and Swietenia macrophylla were grown in sterilized high-, intermediate- and low-fertility soils paired with microbial inoculum from each soil type. Seedling growth, biomass allocation and root colonization by mycorrhizas were quantified after 2 mo. In the field, root colonization by mycorrhizal fungi was unrelated to soil phosphorus across a five-fold gradient of P availability. In the shadehouse, inoculation with soil microbes had either neutral or positive effects on plant growth, suggesting that positive effects of mycorrhizal symbionts outweighed negative effects of soil pathogens. The presence of soil microbes had a greater effect on plant biomass than variation in soil nutrient concentrations (although both effects were modest), and plant responses to mycorrhizal inoculation were not dependent on soil nutrients. Taken together, our results emphasize that soil microbial communities can influence plant growth and morphology independently of soil fertility.

This study examined whether high nutrient concentrations associated with leaf-cutting ant nests influence plant growth and plant water relations in Amazon rain forests. Three nests of Atta cephalotes were selected along with 31 Amaioua guianensis and Protium sp. trees that were grouped into trees near and distant (>10 m) from nests. A 15N leaf-labelling experiment confirmed that trees located near nests accessed nutrients from nests. Trees near nests exhibited higher relative growth rates (based on stem diameter increases) on average compared with trees further away; however this was significant for A. guianensis (near nest 0.224 y−1 and far from nest 0.036 y−1) but not so for Protium sp. (0.146 y−1 and 0.114 y−1 respectively). Water relations were similarly species-specific; for A. guianensis, near-nest individuals showed significantly higher sap flow rates (16 vs. 5 cm h−1), higher predawn/midday water potentials (−0.66 vs. −0.98 MPa) and lower foliar δ13C than trees further away indicating greater water uptake in proximity to the nests while the Protium sp. showed no significant difference except for carbon isotopes. This study thus shows that plant response to high nutrient concentrations in an oligotrophic ecosystem varies with species. Lower seedling abundance and species richness on nests as compared with further away suggests that while adult plants access subterranean nutrient pools, the nest surfaces themselves do not encourage plant establishment and growth.