Post-dispersal fate of seeds dispersed by large primates is well studied but little is known about this process in small frugivores like tamarins. This study in the Amazonian forest of Peru aimed at investigating if characteristics related to the defecation patterns of tamarins (Saguinus mystax and Saguinus fuscicollis) affected short-term post-dispersal seed fate, through secondary seed dispersal by dung beetles and removal by seed predators. Data on dung beetle activity were based on direct observations of 49 defecations while seed fate was studied using semi-controlled experiments (N = 458 for secondary dispersal and N = 398 for predation). Tamarins produce small defecations with a low number of seeds. Thirty-five per cent of defecations were visited by an average of 1.5 dung beetles that usually transport the faeces as pellets. Twenty-four per cent of seeds were buried by beetles at a mean depth of 3.5 cm. With increasing quantities of faecal matter, the probability of secondary seed dispersal increased but not the depth of burial. Seed predation pressure was low (17.6%) after 4 d and higher in faeces of S. mystax than in faeces of S. fuscicollis. Despite their small size, tamarins could be considered as high-quality seed dispersers, with a potential role for forest regeneration.

Lantana camara, a shrub of Central and South American origin, has become invasive across dry forests worldwide. The effect of the thicket-forming habit of L. camara as a dispersal and recruitment barrier in a community of native woody seedlings was examined in a 50-ha permanent plot located in the seasonally dry forest of Mudumalai, southern India. Sixty 100-m2 plots were enumerated for native woody seedlings between 10–100 cm in height. Of these, 30 plots had no L. camara thickets, while the other 30 had dense thickets. The frequency of occurrence and abundance of seedlings were modelled as a function of dispersal mode (mammal, bird or mechanical) and affinities to forest habitats (dry forest, moist forest or ubiquitous) as well as presence or absence of dense L. camara thickets. Furthermore, frequency of occurrence and abundance of individual species were also compared between thickets and no L. camara. At the community level, L. camara density, dispersal mode and forest habitat affinities of species determined both frequency of occurrence and abundance of seedlings, with the abundance of dry-forest mammal-dispersed species and ubiquitous mechanically dispersed species being significantly lower under L. camara thickets. Phyllanthus emblica and Kydia calycina were found to be significantly less abundant under L. camara, whereas most other species were not affected by the presence of thickets. It was inferred that, by affecting the establishment of native tree seedlings, L. camara thickets could eventually alter the community composition of such forests.

Dung beetles (Scarabaeidae subfamily Scarabaeinae) are ubiquitous and play an important role in the removal of animal dung and the dispersal of seeds embedded therein. They exhibit a range of dung-acquisition and burying behaviours, from burying dung directly beneath the dung deposit to rolling dung balls up to several metres. Dung beetles act as important agents for secondary seed dispersal and seed survival: the burial of seeds is said to be of advantage against predators and desiccation (Andresen & Feer 2005, Culot et al. 2009, Feer 1999). In addition, burial of seeds by dung beetles is considered beneficial as seeds are not only deposited within the range of depths that are favourable for seedling establishment but also among organic fertilizer that is said to increase seedling growth rates (Andresen 1999, 2002; Estrada & Coates-Estrada 1991, Shepherd & Chapman 1998).

The relative effects of the elevational gradient and of environmental discontinuities (ecotones) on the structure of a herpetofaunal assemblage in a tropical upland forest were contrasted by means of canonical correspondence analysis. Qualitative descriptors were used to define the elevational positions of the ecotones of interest, namely transitions in forest type and presence/absence of water bodies. The elevational gradient was coded in a form that accommodated different types of community response. Analyses were run for four subsets of the entire assemblage: (1) reptiles, (2) amphibians, (3) amphibians dependent on streams for reproduction, and (4) amphibians that do not use streams for reproduction. All subsets showed a significant relationship with the gradient, which suggested that most species respond to the physical continuum associated with the change in elevation. A response to ecotones was revealed for the amphibian subset only and associated with the presence or absence of watercourses. However, this response disappeared within subsets 3 and 4. A variation partitioning analysis was used to assess the individual and common contributions of gradient and ecotone descriptors to the elevational variation in the structure of subsets 1 and 2. The gradient descriptors explained more variation in the reptile subset than did ecotones, while the reverse was found in the amphibian subset. The dependence of most amphibians on aquatic breeding sites that were not available at all elevations reduced the relative importance of the gradient on the species distributions in subset 2 and accounted for the difference to the reptiles. In all, these findings add to the results of previous null model tests on the same four subsets, where competitive interactions were assigned a minor importance in limiting elevational distributions. The response patterns revealed by the present approach, with ecotones and gradient contrasted in a single analysis, emphasised the role of individual responses to the gradient according to the species' physiological tolerance limits.

The single most important food source for Pteropus rufus at Berenty, in south-east Madagascar, is the pollen of Agave sisalana, a commercial species introduced to the area 60 y ago, which was widely available and constantly eaten by the bats during this 28-mo study. The diet of the bats at this site is unique in this respect when compared with P. rufus elsewhere in Madagascar and with other Pteropus species. The dietary breadth of P. rufus at Berenty is narrow, consisting of only 14 plant species, identified through microsopic faecal analysis and direct field observations, and three unidentified ones. The bats also eat locally cultivated and introduced fruits (Mangifera indica, Psidium cf. cattleianum, Sclerocarya caffra, Cordia sinensis and Hylocereus species) and native and endemic forest species (Tamarindus indica, Celtis philippensis, Ficus megapoda, F. grevei, F. pachyclada and Grewia species). The majority of the plant species used by P. rufus for food are located within the gallery forests of the Mandrare valley. No evidence of adjacent endemic spiny forest species was identified in their diet. Thus, conservation of the remaining gallery forest as well as retention of the sisal plantations is important to maintain the food sources of P. rufus at this site.

Woody plant resprouting has received considerable attention in the last two decades as human disturbances continue to encroach on terrestrial ecosystems globally. We examined the regeneration mechanisms of a Caatinga dry forest in the context of slash-and-burn agriculture and resprouting ability of the local flora. We excavated two old fields (from 32) experiencing early forest regeneration dominated by the tree Pityrocarpa moniliformis (Fabaceae) to map clonal propagation and, in parallel, submitted 260 seedlings from 13 woody plant species to experimental clipping. What seemed to be ‘seedlings’ popping up around P. moniliformis stumps and remaining adults actually were condensed sets of root suckers connected via complex networks of long, ramified shallow horizontal roots without taproots. We mapped respectively 39 and 783 connected root suckers, which summed 96 m and 910 m in root length. Regarding the seedlings, 33% resprouted across nine species with resprouting rates varying between 5–100%. Seedling height before clipping positively influenced resprouting vigour. Our preliminary results suggest that the Caatinga dry forest supports a relatively high proportion of resprouting species, some of them able to clonally propagate and playing an ecosystem-level role by responding to early forest regeneration and high abundance/biomass across both regenerating and old-growth forests.

Litterfall was recorded for one year in Acacia albida woodland in Mana Pools National Park, Zimbabwe. Leaves fell throughout the year, but leaf-fall rate peaked in the wet season. Litterfall was 1.5 t ha−1 year−1, comprising 50% leaves, 20% fruits, 17% ‘fine’ material (mainly frass), 4% flowers and 9% wood and bark. Net above ground production by A. albida trees was 1.7 t ha−1 year−1, including leaf production of 1.0 t ha−1 year−1, twig production of 0.3 t ha-1 year−1 and fruit production of 0.3 t ha−1 year−1. Insects consumed about 26% of leaf production. Net above ground herbaceous production was estimated from rainfall data using regression equations: it was 6.8 t ha−1 year−1 for annual grasses and 2.8 t ha−1 year−1 for forbs. Net above ground primary production in A. albida woodland was 11.3 t ha−1 year−1. The seasonal variations in the nitrogen, phosphorus, potassium, magnesium and calcium concentrations of different A. albida litter components were recorded. The estimated falls of N, P, K, Ca and Mg were 31.1, 2.1, 9.8, 15.0 and 3.4 kg ha−1 year−1 respectively.

The marula (Sclerocarya birrea (A.Rich.) Hochst., Anacardiaceae) has a strongly lignified endocarp or stone which contains several seeds, each of which is within its own locule that is sealed by an individual operculum (Figure 1). The strong casing prevents germination, not by preventing the passage of water to the seeds, but by preventing oxygen from reaching the seeds (von Teichman et al. 1985). It is well known that marula fruits taken from the dung of the African elephant (Loxodonta africana Blumenbach) have more rapid germination than those that have not been eaten by elephants (Dudley 2000, Lewis 1987). This positive impact of elephants on marula germination continues to be considered to be through acid treatment in the digestion system of the elephant (Helm et al. 2011). We hypothesize that the primary mechanism which favours germination is mastication by elephants which physically loosens the opercula, rather than digestive dissolution of the stone. If true, the relevance of this is that only elephants would be the legitimate dispersers of marula seeds, because none of the many other species that are attracted to marula fruits would have jaws powerful enough to loosen the opercula.

Maintenance of high plant diversity in tropical rain forests has been hypothesized to be related to intense seed predation, and studies have shown that the impact of seed-eaters varies according to seed size, forest type and level of disturbance. The hypothesis that seed survival and seedling recruitment depending on seed size, are related to forest type and the intensity of harvesting and stand refinement was therefore tested at Paracou, French Guiana, for three animal-dispersed tree species. Two forest areas, corresponding to two forest types, were selected based on the occurrence of a dominant species, Eperua falcata (Caesalpiniaceae). Two factors were tested: forest type (E. falcata-rich and E. falcata-poor) and level of harvesting (unlogged, low intensity of logging, low intensity of logging and thinning liberation by tree-poison girdling) within each forest type. Overall, there was no effect of species nor of logging treatment within forest type after 6 wk. There was only a significant effect of forest type on seed survival in the large-seeded Carapa procera, a rodent-dispersed species in the Meliaceae. In the two medium-sized seed species, Pradosia cochlearia and Manilkara bidentata, two frugivore-dispersed Sapotaceae, the effect of treatment was overall significant but was also highly variable between plots within treatments. After 1 y, C. procera showed little seedling recruitment due to low seed removal and dispersal, and high seed-seedling predation under all conditions. Neither forest type, nor treatment nested within forest type, affected seedling recruitment in P. cochlearia whereas M. bidentata seedlings were favoured in unlogged conditions at the E. falcata-poor forest type. These results suggest that species characteristics (such as seed size and palatability), or local tree diversity and resources for granivores select for contrasting patterns in tree recruitment between forest type in the rodent-dispersed tree species, and these interact with level of tree harvesting and stand refinement in the other frugivore-dispersed tree species.

The sources of food and the width and overlap of the food niches of Bombus atratus and Bombus morio were determined by field observations and analysis of the pollen loads carried to the colonies by worker bees. The two species together utilized 50 flower species of which 26 were used by both. Solatium paniculatum (Solanaceae) and Psidium guajava (Myrtaceae) were the most frequently visited plants.

The food niche width and niche evenness for both species were similar. The correlation between niche width and niche evenness was non-significant showing that evenness does not depend on niche width. In addition, there was no correlation between niche width and overlap, i.e. overlap varied independently of niche width. A high overlap of food sources utilized by the two species was observed in September, October and November. This may be explained in one of two ways: (a) if B. atratus and B. morio compete for resources, competition would be more intense during those three months; (b) the convergency of both species to the same plant species (Solatium paniculatum and Psidium guajava) would only result in more intensive competition if resources were limiting. However, at that period of the year resources are abundant, therefore although the values of overlap were high, competition need not have occurred.

Variation in herbivory is often associated with plant density and light environment. The effect of these variables was studied on leaf production and herbivory of Manilkara bidentata in Puerto Rico. The major herbivore of M. bidentata is the leaf miner Acrocercops sp. To determine the effect of plant density, twenty-four 20-m × 20-m plots were established and the densities of saplings, juveniles and adults were determined. Leaf production, herbivory and growth were measured on saplings. Plant density was determined in eight 20-m × 20-m plots surrounding the focal plots. The effect of light was determined by comparing leaf phenology, leaf quality and herbivory in vertical and horizontal profiles. Sapling density in 60-m × 60-m plots was associated with herbivory. In the vertical profile, leaf production was continuous only for the canopy: herbivory increased from the canopy (1.3%) towards the understorey (35.6%). In the horizontal profile leaf production was related to light. Saplings in low light environments had narrow peaks in leaf production compared with saplings in high light environments. Differences in leaf phenology did not result in differences in herbivory possibly because of variation in herbivory among leaves. Although many saplings lost more than 80% of new leaf area, there was no detectable effect on growth. High levels of intra-specific variation in herbivory suggest that to better understand plant/herbivore interactions it is necessary to consider all size classes in a population. It is also important to document these pattern across different spatial scales.

A pollination and breeding system study was conducted on a neotropical palm, Astrocaryum vulgare, in Guyana, South America, to better understand its reproductive character evolution, and test the predictability of pollination syndromes. The pollination syndrome approach was used because it integrates characteristics of flowers and their pollinators into an evolutionary framework that allowed experimental testing of predictions. The flowers of A. vulgare displayed traits that were typical of both beetle and wind pollination syndromes. The protogynous inflorescences produced heat and odour during nocturnal anthesis, had numerous stamens with copious, light pollen, and were visited by hordes of beetles that used the inflorescences as feeding, mating and oviposition sites. In contrast, some of these features, such as numerous stamens with copious, light pollen, a high pollen to ovule ratio, and no obvious production of visitor rewards, were also typical of the wind pollination syndrome. However, floral rewards appeared to be tissues of the fleshy staminate petals and pollen that were readily devoured by the beetles. In addition to the Coleoptera, insect visitors to A. vulgare inflorescences included several species of Hymenoptera, Diptera and Orthoptera. However, only Nitidulidae and Curculionidae beetles were effective insect pollinators. Pollination treatments showed that wind pollination was possible, but fruit set was significantly higher for female flowers visited by beetles. Although a pollen/ovule ratio of 50 000:1 and outcrossing index confirmed an outcrossing breeding system, pollination experiments suggested that A. vulgare had the potential for self pollination. Therefore, the breeding system might be best classified as facultatively xenogamous (cross fertilizing). The predictive value of potential pollinator agents for A. vulgare was inadequate because its floral traits were indicative of both cantharophilous and anemophilous pollination syndromes.

This study was conducted in a woodland savanna in western Venezuela exclosed from grazing and burnt once a year towards the end of the dry season. Mean annual rainfall is 1500 mm, with a strong seasonality.

Two cohorts of seedlings of Andropogon semiberbis were tagged and monitored for up to three years. Several variables such as survivorship, plant size, seedling density, fire damage and distance to the nearest adult were measured or estimated. Two burning experiments to measure survivorship before and after fire, and two seedling-growth experiments to assess competitive interference from adult plants of three grass species were performed.

The highest mortality takes place during the dry season and is due to fire. This decreases as the plants get bigger due to increasing structural complexity of the clump by growth which gives added protection to the meristems. Other mortality factors such as desiccation, uprooting and shading seem to be important during the wet season, when mortality rate is relatively constant. Survivorship during the first year and after three years is strongly correlated to the size attained by the end of the first growing season.

Seedling densities are rather low and do not seem to play any role in survivorship in this population. Adult interference with seedling growth decreases with distance and seems to be due to root competition, although there is a tendency toward increased foliage interference related to the canopy structure of adult plants.

Great apes are considered to be important seed dispersers in palaeotropical habitats due to their large body size (this would be reflected in the amount of foods consumed) and large home ranges (Poulsen et al. 2001, Wrangham et al. 1994). Furthermore, the great apes might process seeds in a way that maintains their viability (Lambert 1999). Previous studies of seed dispersal by great apes have generally taken the form of lists of seeds found in their faeces (Voysey et al. 1999a, Wrangham et al. 1994), effects of passage through their guts on seed germination (Idani 1986, Wrangham et al. 1994), and effects of dispersal location on germination/seedling survival (Gross-Camp & Kaplin 2005, Rogers et al. 1998, Voysey et al. 1999b). In contrast with the richness of reports about aspects of seeds after their dispersal, few studies have investigated the dispersal pattern of seeds. In this study, we report on the estimated distances of seed dispersal by the wild bonobo (Pan paniscus Schwartz), a species of great ape.

We analysed the effect of a hurricane on a plant–ant network and on vegetation cover. Plant cover was sampled using linear sampling in several vegetation types: deciduous forest, a dry forest, sand dune pioneers, sand dune scrub, ecotone of freshwater marsh, deciduous forest and dune scrub, and mangrove forest. We sampled ant–plant interactions and vegetation cover before and after Hurricane Karl hitting (September 2010) the central coast of the state of Veracruz, Mexico. The pre-hurricane network consisted of 16 plant and 25 ant species in 52 associations. The post-hurricane network consisted of 17 plant and 20 ant species in 56 associations. We found a significant decrease in the total linear cover of EFN-bearing plants between October 2009 (646 m, no hurricane effect) and October 2010 (393 m, after hurricane Karl) (total sample length 2025 m). Both networks were significantly nested (0.999 and 0.973, P < 0.001), suggesting that network topology remained similar. Our results show changes in several network characteristics and species proportions. The number of plant species that contributed to nestedness vs. idiosyncratic species did not differ significantly in the pre-hurricane network, while the number of plant species that contributed to nestedness vs. idiosyncratic species did differ significantly in the post-hurricane network. The number of ant species that contributed to nestedness vs. idiosyncratic species differed significantly in the pre-hurricane network, and also in the post-hurricane network. Differences in nestedness contributions of species before and after the hurricane reflect an alteration from a generalized, highly nested, more stable pre-disturbance network, to a more low-degree or specialized network (i.e. fewer interactions among generalist species, those species with the most associations). The maintenance of important core components of the network after a huge disturbance, suggests a short-term resilience typical of mutualistic networks.

The present study examined the effect of a catastrophic cyclone (Aila) on ichthyofaunal assemblages in a tidal river of the Sundarban Delta. Sampling in six stations with a gill-net of 20-m length and 1-cm mesh size resulted in the collection of 63 species in a pre-Aila survey. Among them, 16 species were not available in the year after the cyclone. However, 12 new species were added to the assemblages in the post-Aila year during which 59 species were recorded. Analysis of Similarity (ANOSIM) confirmed significant changes in fish assemblages after the cyclone with a corresponding reduction of the species diversity and variation in the seasonal pattern of abundance. Hydrological parameters also differed with a significant surge in nutrient concentrations. Tolerance to low dissolved oxygen seemed to be a determinant factor as evident from the higher abundance of certain fishes viz. Harpadon nehereus, Liza parsia, Pampus argentius, Tenualosa ilisha and Toxotes chatareus during post-Aila year. Despite the recovery of the ichthyofaunal assemblages at the later stage of the study, a strong seasonal variation was persistent. The study therefore suggests that environmental variation in terms of increasing temperature and salinity elicit greater response in an estuarine community than temporary natural disturbances even as severe as cyclones.

Evaluation of proximate mechanisms (e.g. dispersal, immigration, competition, facilitation) that determine patterns of assemblage or community structure is an important step in the development of paradigms in ecology. Host–parasite systems are useful for such studies because host-parasite assemblages are easily defined units of study, each host individual harbours a sample from a community or assemblage, and many host species are common, providing replicate samples. I used ectoparasite assemblages from Noctilio leporinus collected from Paraguay to evaluate effects of host sex and body size on ectoparasite abundance and to determine if these assemblages exhibit a nested pattern of species co-occurrence. A total of 533 ectoparasites representing seven species and four families were collected from 28 hosts. Abundances of Paradyschiria fusca and Noctiliostrebla aitkeni responded positively to host body size. Host sex had no affect on ectoparasite abundances. Streblid bat fly assemblages from Noctilio leporinus were strongly and significantly nested. Abundances of all species of streblid were positively correlated with one another with Pearson product moment correlation coefficients between 0.424 and 0.646. Competition does not appear to affect community structure of streblids from Paraguayan Noctilio leporinus. Independent responses of species of streblid to host characteristics appear to mould assemblage structure in this system.

Large-scale natural disturbances, such as hurricanes, can have profound effects on animal populations. Nonetheless, generalizations about the effects of disturbance are elusive, and few studies consider long-term responses of a single population or community to multiple large-scale disturbance events. In the last 20 y, two major hurricanes (Hugo and Georges) have struck the island of Puerto Rico. Long-term population trends of 17 species of terrestrial gastropod were evaluated to determine whether gastropods respond to hurricane disturbances in a consistent fashion. Some species increased, some decreased, and some exhibited no simple trend in density or spatial variability following disturbance. In addition, some species responded differently to the two hurricanes with respect to population density, absolute spatial variability, or relative spatial variability. Population responses probably hinge on trade-offs between sensitivity to microclimatic changes and resource availability resulting from the relocation of biomass from the canopy to the forest floor. The historical context within which a hurricane occurs may be as important, or more so, than the intensity of the storm, per se.