This research investigates the influence of environmental parameters that are known to affect bdelloid rotifer species richness and composition in temperate zones on the genus Rotaria in tropical zone. Our study analysed species richness and composition of the genus Rotaria from 390 samples collected from several types of aquatic habitats in Thailand. Coordinates, elevation, limnological parameters such as water temperature, conductivity, total dissolved solids, salinity, dissolved oxygen and pH were measured. A total of nine species was recorded. Of these, one species, Rotaria macrura (Ehrenberg, 1832), was a new record for Thailand and new to the oriental region, and was a yet undescribed species, Rotaria sp. The species diversity of this genus increased from eight to 10 species. The presence or absence of the genus Rotaria was significantly influenced by dissolved oxygen and habitat type. For the samples where the genus occurred, species richness was not affected by any of the limnological or bioclimatic variables. Differences in species composition were affected only by habitat type. The results support former suggestions that common abiotic parameters do not seem to strongly influence diversity in bdelloids, whereas major ecological differences between habitats influence bdelloid occurrence.

Accurate measurements of seed rain are important for understanding tree reproduction (Greene & Johnson 1994), forest regeneration (Cole et al. 2010, Cubiña & Aide 2001, Howe et al. 2010, Zahawi & Augspurger 2006), forest ecology (Muller-Landau et al. 2008, Terborgh et al. 2011) and maintenance of community diversity (Harms et al. 2000). Seed traps generally consist of a bucket or net of a fixed area suspended 0.3–1 m above the ground, and seeds are typically collected once or twice per month. An implicit assumption of all seed-rain studies is that traps do not influence seed dispersal. Should birds perch on and defecate seeds into seed traps, seed abundance will be overestimated. This behaviour could produce a directional bias if birds perch on seed traps in one habitat more than others. To our knowledge, no study has considered this potential bias.

Although seed dispersal plays a critical role for plant regeneration, the long-term benefits of frugivores for recruitment success have been poorly explored. We evaluated the relative importance of tree species abundance and of frugivore-related factors for successful plant recruitment on 18 tree species in a lowland Colombian rain forest. We combined census data from four 1-ha plots of trees (>10 cm dbh), saplings (1–5 cm dbh) and seedlings (<1.7 m) with a dataset describing tree–frugivore interactions. Seedling abundance was higher for large-seeded species dispersed by the spider monkey, while sapling abundance was higher for large-seeded species dispersed by birds. The identity of the dispersal agent and its interaction with seed size explained 20–30% of the total variance in seedling and sapling abundance across scales. Seed size consistently influenced the species abundance of seedlings and saplings across scales, but in opposite ways. These developmental changes suggest that what is beneficial to seedlings is not necessarily beneficial to saplings. Species identity explained 10–50% of the total variance in seedling and sapling abundance among and within 1-ha plots. Overall, our findings suggest that recruitment success is context-dependent as the relative importance of the different variables addressed may shift along spatial and temporal scales.

Animals which migrate by flying should be subject to selection for optimal wing characteristics that maximize energy efficiency during migration. We investigated wing shape and wing area variation in the Globe Skimmer Dragonfly Pantala flavescens, which has the longest known migration of any insect. Wing shape and wing area differences between individuals in southern Peninsular India, and migrating individuals at a stop-over site on the Maldives, were compared. Results suggest that individuals which successfully reached the Maldives, on their way from India to Africa, had a broader wing base and an overall more slender wing shape than individuals in southern India. Contrary to our expectations, wing area did not differ significantly in most of our comparisons between southern India and the Maldives, suggesting that wing shape is more important than wing area for successful migration in P. flavescens. The results provide indirect evidence of natural selection on wing shape in a migrating dragonfly.

Greenhouses are inflated structures with transparent covering that are used to grow crops under controlled climatic conditions. Crops are protected from extreme climate-related events by being enclosed. Furthermore, the greenhouse design ratio impacts the temperature and humidity distribution profile uniformity as well as the greenhouse. As a result, by effectively designing the greenhouse structure, building materials, dimensions, and shapes, the cost of cooling management strategies can be reduced. Structures with changed arch shapes showed to be more effective at reducing greenhouse cooling demands in hot areas. To demonstrate the tropical region’s inherent capabilities for generating a proper atmosphere for plant development, the optimal temperature, humidity, light, and PH for greenhouse production of crops were supplied. Greenhouse cooling systems are dominated by local environmental characteristics that have an immediate impact on their indoor climatic conditions. Photovoltaic systems in greenhouses have proven technological capacity in real-world settings in this area. This could increase the energy efficiency of some agrivoltaic greenhouse design options.

We studied the vegetation and soil properties of a dry forest that had once been disturbed in central Myanmar using 30 quadrats (20 × 20 m) established in 2012. For 30 species, the overall density was 706 individuals ha−1, and the basal area was 2.92 m2 ha−1. The forest was a mosaic of six community types, each of which was dominated by a single species. Dominant species that were capable of resprouting accounted for 47–78% of the total density and 56–83% of the basal area of the communities. We related seven soil properties to the vegetation patterns using canonical correspondence analysis (CCA). The CCA results highlighted remarkable associations of species such as Acacia catechu, Dalbergia paniculata, Terminalia oliveri and Millettia multiflora with soil texture. Acacia inopinata was associated with a high soil pH (i.e. 9–10), and Terminalia tomentosa was associated with soil hardness. Our results indicate that secondary succession of a dry forest is not initially led by pioneer species, but instead, by superior competitors capable of resprouting, and that species distributions are primarily determined by the filtering effects of edaphic conditions. We believe that the dry-forest species retain their soil–species relationships despite heavy disturbances.

Mistletoes are considered keystone species on woodlands and savannas worldwide, providing a food resource for a diversified fauna, as well as a nutrient-enriched litter. Infections can be large (∼1–3 m) and, in some parts of the Amazonian savannas, parasitize up to 70% of hosts locally. Despite these facts, biomass of mistletoes is rarely investigated. Here we constructed allometric models to predict the biomass stock of the shrubby mistletoe Psittacanthus plagiophyllus in an Amazonian savanna. In addition, we determined whether host size could be used as a proxy for mistletoe biomass. Finally, we compared the biomass of mistletoes with that of trees, to evaluate their relative importance. We have shown that: (1) biomass of leaves (46.1% ± 13.5%) are as important as of stems (47.8% ± 13.5%), and relative contribution of stems increases as plant grows; (2) the model including width, breadth and vertical depth was the best (SE = 0.39, R2 = 0.9) for predicting individual mistletoe biomass; (3) mistletoe load and biomass per host had a positive, but weak (R2 = 0.11 and 0.09, respectively), relationship with host size, and thus such host information is a poor predictor of mistletoe biomass; and (4) in comparison with trees, mistletoes constituted less than 0.15% (0.5–22 kg ha−1) of the total above-ground biomass, suggesting that this life-form is irrelevant to the local biomass stock despite its unequivocal biological importance.

Understorey wildfires harm tropical forests by affecting natural regeneration, but the trajectories of fire-disturbed forests after disturbance are poorly understood. To fill this gap, we conducted experimental burns in a transitional forest between the Amazon forests and the Brazilian Savanna (Cerrado) and investigated their effects on plant community diversity of regeneration. The experiment consisted of three 50-ha plots that between 2004 and 2010 were burned either annually (six times), every three years (thrice) or not at all (Control). To evaluate early post-fire recovery, we recorded grass occurrence and regenerating stems (≤1 cm in diameter at breast height). We noted that high fire-frequency plots had a reduction of species richness (62%) and abundance (84%) and were associated with floristic and structural changes, dominance of few species and increase of grass colonization when compared with low fire-frequency. We observed that resprouts were the main pathway for forest restoration in both burned regimes, particularly in low fire-frequency. However, the forest can recover from fires by means of resprouting, until a threshold in fire frequency is reached, when resprouts and seedlings declined for most of the species, with a few fire-tolerant species becoming dominant.

In the tropics, limestone caves in karstic areas are known for their unique biodiversity. However, many caves remain unstudied and little is known about underlying gradients that determine diversity and biomass in aquatic microhabitats. Here, we sampled zooplankton and benthos in a set of 12 aquatic caves, locally called closed cenotes in Yucatán, Mexico. Our aim was to explain diversity patterns and differences in biomass with particular attention for correlations between bat colony characteristics and other biota. Compared with caves that support photosynthesis, diversity was low with an average of four planktonic and two benthic species in these dark caves. Undetectable phosphorus concentrations in the water suggest this nutrient is limiting. Several associations hint at a potential link between bat abundance and functional guild composition, water quality and aquatic biota. As such, more bats were linked to higher nitrate concentrations. Yet this was not translated to higher invertebrate biomass, probably since phosphorus is limiting. Overall, the trends found in this survey suggest that bats could be important as fertilizers of the caves although mechanistic links that mediate the flux of nutrients need to be confirmed experimentally.

In lowland tropical and temperate forests, nitrogen (N) and phosphorus (P) resorption from senesced leaves may reflect a mechanism of conservation of a limiting nutrient (Edwards & Grubb 1982, Killingbeck 1996, Proctor et al. 1989, Scott et al. 1992, Songwe et al. 1997, Vitousek & Sanford 1986). At the ecosystem level it has important implications for element cycling. The nutrients which are resorbed during leaf senescence are directly available for further plant growth, which makes a species less dependent on current nutrient uptake. Nutrients which are not resorbed, however, will be circulated through litterfall in the longer term (Aerts 1996).

The magnitude of facilitation by shelter-building engineers on community structure is expected to be greater when they increase limited resources in the environment. We evaluated the influence of local environmental context on the colonisation of leaf shelters by arthropods in a Mexican evergreen tropical rainforest. We compared the species richness and abundance of arthropods (total and for different guilds) colonising artificially rolled leaves in habitats differing in understory heterogeneity (forest edge > old-growth forests > living fences). Arthropod abundance of the most representative arthropod taxa (i.e., Araneae, Blattodea, Collembola and Psocoptera) colonising the rolled leaves was greater at forest edge, a trend also observed for average arthropod abundance, and for detritivore and predator guilds. In addition, fewer arthropod species and individuals colonised the rolled leaves in the living fence habitat, a trend also observed for most arthropod guilds. As forest edge is expected to have a greater arthropod diversity and stronger density-dependent interactions, a greater limitation of refuges from competitors or predators may have determined the higher colonisation of the rolled leaves in this habitat. Our results demonstrate that local environment context is an important factor that affects the colonisation of arthropods in leaf shelters.

Plant survival and growth in tropical rain forest are affected by different biotic and abiotic forces. As time elapses and plants grow the relative importance of such forces as regeneration inhibitors and/or facilitators may change according to habitat and species. To detect within- and among-species divergences in performance over time in different habitats we followed, for nearly a decade, the survival, growth and herbivory of seedlings of the native tree species: Chrysophyllum pomiferum, Micropholis venulosa and Pouteria caimito. In Central Amazonia, young seedlings were planted into old-growth and secondary forests dominated by Vismia spp. One year after planting, C. pomiferum ranked first (i.e. fast growth, fewer dead and less herbivory) for both habitats, followed by M. venulosa and P. caimito. Initial trends changed over time. In the long term, M. venulosa ranked first for both habitats, followed by C. pomiferum and P. caimito ranked consistently lowest. Within-species divergences in growth and herbivory were greater in secondary forest. Initial seedling responses cannot always be used to predict species persistence in the long term. Contrary to previous estimations, old-growth-forest species can persist under Vismia spp. stands, at least when planted.

Compounds of the 20 elements needed by living organisms are relatively soluble in water and therefore vulnerable to being leached and lost from terrestrial ecosystems during mineralization. Intact systems have thus acquired retention mechanisms that sequester nutrients and minimize losses. Such mechanisms should be particularly important where rainfall is very high but direct evidence of retention mechanisms in tropical forests is scarce (Snaddon et al. 2012, Turner et al. 2007).

The herpetofauna of a floodplain monsoon rain forest in northern Australia is composed primarily of species from non rain forest habitats. The majority of frog species use rain forest as a seasonal refuge, and there is a marked increase in numbers during the dry season. Faunal richness lies within limits expected on the basis of the length of the dry season and species richnesses of non-Australian faunas. There are few lizard species and an abundance of frog species (none of which is a rain forest specialist) in comparison to rain forest herpetofaunas in other tropical regions. The impoverished lizard fauna, and the paucity of rain forest specialists may be because (a) seasonal invasion of rain forest by frogs prevents evolution of, or colonization by, specialists or (b) rain forest specialists may not have been able to cross semiarid habitats separating the Northern Territory from eastern Australian rain forests. The herpetofaunas of monsoon forests in Cape York Peninsula may provide a means of distinguishing between these hypotheses.

Despite its high plant diversity, the Amazon forest is dominated by a limited number of highly abundant, oligarchic tree and liana species. The high diversity can be related to specific habitat requirements in many of the less common species, but fewer studies have investigated the characteristics of the dominant species. To test how environmental variation may contribute to the success of dominant species we investigated whether the vital rates of the abundant liana Machaerium cuspidatum is sensitive to canopy height, topographic steepness, vegetation density, soil components and floristic composition across an Ecuadorian Amazon forest. The population was inventoried in 1998 and in 2009. Plants were divided into seedling-sized individuals, non-climbers and climbers. Out of 448 seedling-sized plants 421 died, 539 of 732 non-climbers died, and 107 of 198 climbers died. There was weak positive effect of dense understorey on the relative growth rate of climbers. The mortality of seedling-sized plants was higher in areas with intermediate slope, but for larger plants mortality was not related to environmental variation. The limited sensitivity of the vital rates to environmental gradients in the area suggests that ecological generalism contributes to the success of this dominant Amazonian liana.

Seed dispersal effectiveness (SDE) is related to the role of seed dispersal agents in realizing the reproductive potential of plants through seed dispersal and subsequent plant recruitment. The SDE of a given seed disperser may vary spatially and temporally, with important implications for our understanding of the mutualistic relationships involving plants and frugivores. Here we observed 22 frugivorous bird species visiting an individual tree (Cabralea canjerana) over a 9-y period in a fragment of Atlantic forest in south-eastern Brazil to document the temporal variation in SDE. The quantitative (that takes into account the frequency of feeding visits to the focal plant and the number of fruits removed per visit) and qualitative (that considers the probability of seed deposition on a suitable site for plant recruitment) components of SDE varied in two and one order of magnitude both among bird species and among years within bird species, respectively. As a result, the SDE of bird species fluctuates over the years, especially for a migratory species that is the main seed disperser of C. canjerana (Chivi vireo Vireo chivi) whose quantitative component (i.e. the product of visit and fruit intake rates) varied from 3.0 to 7.1. This study illustrates the dynamic nature of the seed-dispersal environment to which a plant is subjected to over the course of its life, which has important consequences for the plant's individual fitness.

Rooting differentiation between established trees and grasses has been well documented in savannas, but it remains unclear to what extent tree-grass rooting differences affect competition between newly established seedlings and grasses. To examine this question, a greenhouse experiment was conducted at the University of Missouri, USA. Twenty 3-mo-old seedlings each of two African savanna tree species (Acacia nigrescens and Colophospermum mopane) were grown for 8 mo with two crossed factors: grass competition and irrigation depth. Strong negative effects of grass competition on final seedling biomass and leaf photosynthetic and stomatal conductance occurred in both tree species, but no effects of irrigation depth were detected. There was a clear tree species by grass competition interaction, suggesting interspecific variation in competitive response. The results emphasize the importance of below-ground competition with grasses for physiological and morphological responses of tree seedlings, while minimizing the importance of tree-grass rooting depth differences as a factor in modulating the competitive response of trees to grasses at the seedling stage.

In South-East Asian tropical plants, the excess production of reproductive organs is believed to be controlled by resource booms. However, the continuously flowering shrub Dillenia suffruticosa (Dilleniaceae) is often infested by fruit predators and occasionally produces fruits where mature seeds are absent. These reproductive features may support an alternative hypothesis for excess production of reproductive organs: the reproductive assurance hypothesis. We marked 1190 reproductive organs in 180 inflorescences of 41 plant individuals and examined the relationships among the reproductive organ features and the effects of both climate and predators. During the flower budding stage, the fate of reproductive organs was primary climate-induced. The percentage of flower/fruit abscission increased as the cumulative temperature and photosynthetically active radiation (PAR) decreased and the cumulative precipitation increased, supporting the resource boom hypothesis. Insect predation was the most common fate of immature fruits. As PAR increased, the prevalence of insect predation and production of mature seed increased. At a reduced PAR, the production of fruits with many immature seeds could serve as compensatory reproductive organs for insect predators, consistent with the reproductive assurance hypothesis. The excess production of reproductive organs might be a result of adaptation to climate fluctuations in the South-East Asian tropics.

During their ontogeny many organisms exhibit size and/or stage-specific variability in a variety of features related to morphology and ecology, leading to a shift in the ecological niche between size- or stage groups. We analysed such ecological shifts between four larval stage groups in each of two syntopic species of frogs (a total of 5870 individuals) in two West African savanna ponds in Côte d'Ivoire. We hypothesized and confirmed differences between stage groups in ecological variables related to microhabitat and feeding niche. Stage groups differed up to 1‰ in δ15N and 1.5‰ in δ13C isotopic signatures, up to 10 cm in selected water depth, up to 6 m in distance to the pond's edge, and in the coverage of submerged vegetation (range = 10–50%). However, the hypothesis that tadpoles with generalized mouthparts (Kassina spp.) exhibit more pronounced ontogenetic shifts in food-web position than a specialized filter-feeding species (Phrynomantis microps), and that differences between larval stages are more pronounced in a heterogeneous habitat (offering more choices of habitat and food niches) than in a homogeneous habitat (offering less choices) was only partly confirmed. This study underlines that potential niche shift during different ontogenetic stages is an important factor to be considered in ecological studies.