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Frugivory in tropical forests is a major ecological process as most tree species rely on frugivores to disperse their seeds. However, the underlying mechanisms driving frugivore-plant networks remain understudied. Here, we evaluate the data available on the Afrotropical frugivory network to identify structural properties, as well as assess knowledge gaps. We assembled a database of frugivory interactions from the literature with 10 000 links, between 807 tree and 285 frugivore species. We analysed the network structure using a block model that groups species with similar interaction patterns and estimates interaction probabilities among them. We investigated the species traits related to this grouping structure. This frugivory network was simplified into 14 tree and 14 frugivore blocks. The block structure depended on the sampling effort among species: Large mammals were better-studied, while smaller frugivores were the least studied. Species traits related to frugivory were strong predictors of the species composition of blocks and interactions among them. Fruits from larger trees were consumed by most frugivores, and large frugivores had higher probabilities to consume larger fruits. To conclude, this large-scale frugivory network was mainly structured by species traits involved in frugivory, and as expected by the distribution areas of species, while still being limited by sampling incompleteness.

Changes in biodiversity may impact infectious disease transmission through multiple mechanisms. We explored the impact of biodiversity changes on the transmission of Amazonian leishmaniases, a group of wild zoonoses transmitted by phlebotomine sand flies (Psychodidae), which represent an important health burden in a region where biodiversity is both rich and threatened. Using molecular analyses of sand fly pools and blood-fed dipterans, we characterized the disease system in forest sites in French Guiana undergoing different levels of human-induced disturbance. We show that the prevalence of Leishmania parasites in sand flies correlates positively with the relative abundance of mammal species known as Leishmania reservoirs. In addition, Leishmania reservoirs tend to dominate in less diverse mammal communities, in accordance with the dilution effect hypothesis. This results in a negative relationship between Leishmania prevalence and mammal diversity. On the other hand, higher mammal diversity is associated with higher sand fly density, possibly because more diverse mammal communities harbor higher biomass and more abundant feeding resources for sand flies, although more research is needed to identify the factors that shape sand fly communities. As a consequence of these antagonistic effects, decreased mammal diversity comes with an increase of parasite prevalence in sand flies, but has no detectable impact on the density of infected sand flies. These results represent additional evidence that biodiversity changes may simultaneously dilute and amplify vector-borne disease transmission through different mechanisms that need to be better understood before drawing generalities on the biodiversity-disease relationship. 1 Introduction 2 Material and methods 2.1 Sampling 2.2 Laboratory 2.3 Bioinformatic analyses 2.4 Estimating mammal diversity from individual dipteran blood meals 2.5 Effect of mammal diversity on Leishmania transmission 3 Results 3.1 Sampling and molecular analyses 3.2 Sand fly, vertebrate and Leishmania identifications 3.3 Statistical analyses 4 Discussion

International audience; Tropical forests harbor the greatest terrestrial biodiversity and provide various ecosystem services. The increase of human activities on these forests, among which logging, makes the conservation of biodiversity and associated services strongly dependent on the sustainability of these activities. However the indicators commonly used to assess the impact of forest exploitation, namely species richness and biomass, provide a limited understanding of their sustainability. Here, we assessed the sustainability of common forest exploitation in the Guiana Shield studying the recovery of two ecosystem services i.e. carbon storage and wood stock, and an ecosystem function i.e. seed dispersal by animals. Specifically, we compared total and commercial biomass, as well as functional composition in seed size of animal-dispersed species in replicated forest plots before and 27 years after exploitation. Species richness is also studied to allow comparison. While species richness was not affected by forest exploitation, total and commercial biomass as well as seed size of animal-dispersed species decreased 27 years after exploitation, similarly to forests affected by hunting. These results show that ecosystem services and function likely did not recover even at the lowest intensity of forest exploitation studied, questioning the sustainability of the most common rotation-cycle duration applied in the tropics.

1. Arboreal camera trapping is a burgeoning method providing a novel and effective technique to answer research questions across a variety of ecosystems, and it has the capacity to improve our understanding of a wide range of taxa. However, while terrestrial camera trapping has received much attention, there is little guidance for dealing with the unique challenges of working in the arboreal realm. 2. Our review draws on the expertise of researchers from six continents and the broader literature to investigate the advantages and disadvantages of arboreal camera trapping, and challenges to consider when using this technology. We also include mini-guides with detailed information on the current arboreal camera trap literature, mounts used to install arboreal cameras, tree climbing pointers and safety tips, methods for deploying cameras without climbing, and tips for managing interference with camera function. 3. We find that arboreal camera traps have been most commonly used in the study of mammals in forests, however there is potential for this method to be applied to a broad range of habitats including urban areas, and taxa such as birds, amphibians, invertebrates, and plants. Methods in arboreal camera trapping could be improved by developing a greater understanding of the factors affecting detection of species. The most common challenges of arboreal camera trapping are camera placement and camera site access. These can be overcome by understanding correct camera orientation, managing potential sources of interference in front of cameras, utilizing appropriate cameras mounts, and training researchers properly. 4. Given the benefits and opportunities presented by arboreal camera trapping, it is likely to become an ever-more popular method of studying arboreal species and systems. The information synthesized in this review provides guidance for future studies to help direct more reliable and robust ecological inferences from arboreal camera trapping.

Endozoochory is an essential plant-animal interaction in tropical forests, involving the swallowing and defecation of seeds. To better understand whether anatomical traits (i.e. body mass and skull dimensions) are good predictors of seed dispersal in mammals we studied the relationships between morphology, fruit and seed size and seed dispersal distance across three orders: Chiroptera, Primates, and Carnivora. Our results revealed that body mass is an important driver of the size of ingested seeds for all orders and of the seed dispersal distance produced by Primates. In addition, the distance between the molars, jaw length, and jaw gape are good predictors of the size of ingested seeds. These results show how body mass and cranial anatomy constrain ingested seed size and dispersal distance across mammals and reinforce the importance of maintaining functional diversity in seed dispersers to maintain tropical forest structure and regeneration.

Rodents can be important in seed dispersal through their scatterhoarding behaviour, yet, the seed traits that are most influential in seed removal by Afrotropical scatterhoarding rodents remains unclear. Here, we investigated the effect of seed size and nutrient content of four seed species on the scatterhoarding behaviour of rodents in an Afromontane forest, Ngel Nyaki forest, Nigeria. To do this we marked with thread-tags the seeds of Santiria trimera, Beilschmedia mannii, Carapa oreophila and Anthonotha noldeae and observed their fate. We predicted that (1) caching frequency would be higher for larger than smaller seed species; (2) caching frequency would be higher for nutrient-rich than nutrient-poor seeds; (3) larger seeds would be taken across farther distances; and (4) survival of cached seeds would be higher for nutrient-rich seeds. In contrast to studies elsewhere we found no difference in caching probabilities based on seed size, although nutrient-rich (high fat content) seeds had a higher probability of being predated than seeds with lower fat content. Larger and smaller seeds were dispersed over the same distances and nutrient-poor (high fibre content) seeds survived longer in seed caches. Overall, our findings suggest that large, nutrient-rich seed species are less likely to be dispersed by rodents.

Tropical forests are facing threats that may affect the dynamics of seed dispersers which participate in the forest regeneration. To implement appropriate conservation programs, it appears necessary to monitor seed dispersers and to estimate their response to local changes. Here, we used non-invasive ecoacoustic methods to monitor the activity of a canopy bird, the White-throated toucan, Ramphastos tucanus, a major seed disperser and flagship species of the Amazonian forest. We deployed nine acoustic recorders over 29 days along a road that connects French Guiana to Brazil. We used template matching to automatically detect the vocalizations of R. tucanus. This method, which can easily be repeated with limited human expertise, detected 1748 recordings with R. tucanus vocalizations. A GLMM analysis was applied to test for a possible effect of habitat type and human activity, while accounting for time of the day and rainfall. The number of vocalizations varied according to time of the day with peaks at dawn and dusk. The number of vocalizations did not differ significantly among sites, they were not affected by habitat type, and they were only marginally influenced by human activity. These results indicate that the vocal activity of a key conservation species can be monitored automatically in a non-invasive way. The species targeted, R. tucanus, does not seem to be significantly impacted by the road and local human activity. This might be related to the mobility of the species, which can easily cross the road, as well as low local forestry pressure.

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International audience

We retrace the development of tropical phenology research, compare temperate phenology study to that in the tropics and highlight the advances currently being made in this flourishing discipline. The synthesis draws attention to how fundamentally different tropical phenology data can be to temperate data. Tropical plants lack a phase of winter dormancy and may grow and reproduce continually. Seasonal patterns in environmental parameters, such as rainfall, irradiance or temperature, do not necessarily coincide temporally, as they do in temperate climes. We review recent research on the drivers of phenophase cycles in individual trees, species and communities and highlight how significant innovations in biometric tools and approaches are being driven by the need to deal with circular data, the complexity of defining tropical seasons and the myriad growth and reproductive strategies used by tropical plants. We discuss how important the use of leaf phenology (or remotely‐sensed proxies of leaf phenophases) has become in tracking biome responses to climate change at the continental level and how important the phenophase of forests can be in determining local weather conditions. We also highlight how powerful analyses of plant responses are hampered at many tropical sites by a lack of contextual data on local environmental conditions. We conclude by arguing that there is a clear global benefit in increasing long term tropical phenology data collection and improving empirical collection of local climate measures, contemporary to the phenology data. Directing more resources to research in this sector will be widely beneficial.

Animal-mediated seed dispersal is recognized to influence the spatial organization of plant communities but little is known about how frugivores cause such patterns. Here, we explored the role of hornbills and primates in generating recruitment foci under two zoochoric trees, namely Staudtia kamerunensis (Myristicaceae) and Dialium spp. (Fabaceae - Caesalpiniodea) in a forest-savanna mosaic landscape in D.R. Congo. We also examined the influence of the availability of fruits in the neighborhood and the amount of forest cover in the landscape on such clumping patterns. The density and species richness of hornbill-dispersed and the density of primate-dispersed seedlings were significantly higher under Staudtia kamerunensis trees than at control locations. However, we did not find such patterns under Dialium spp. trees compared to control locations except for the density of hornbill-dispersed seedlings which was lower at control locations. Also, we found that an increasing amount of forest cover in the landscape was associated with an increase in the density of hornbill-dispersed seedlings, although the tendency was weak (R 2 = 0.065). We concluded that S. kamerunensis acts as a recruitment foci and plays a structuring role in Afrotropical forests. Hornbills were probably the main frugivore taxon responsible for the clumping under that tree and appear as a key ecological component in fragmented and disturbed landscapes where the diversity of large frugivores such as primates is reduced. Our findings improve our understanding of the causal mechanisms responsible for the spatial organization of tropical forests.

Scatter-hoarding by rodents is expected to benefit palm recruitment by allowing cached seeds to escape predation and to colonize new areas, but evidence that seedlings emerge from cached seeds is scarce. We aimed to assess to what extent seedling establishment of two palm species (Astrocaryum aculeatissimum and Attalea humilis) is favoured by seed caching by rodents in a large Atlantic Forest remnant. We mapped the location of conspecific seedlings within circular plots of 15-m radius around five adult individuals of each palm species, checking if seedlings established from dispersed (>2 m from parent palms) or non-dispersed seeds (0–2 m from parent palms), and from buried or unburied seeds. We found a total of 42 A. aculeatissimum seedlings and 16 A. humilis seedlings. Nearly all (98%) seedlings established from seeds dispersed away from parents (mainly located 10–15 m from parents), and 83% and 75% of seedlings of A. aculeatissimum and A. humilis, respectively, established from seeds buried in the soil. Results show that both palm species depend almost entirely on caching of seeds by rodents to establish seedlings. Our study suggests that checking for endocarps associated with established seedlings can accurately estimate the process behind seedling establishment, improving our understanding about the net outcome of seed caching for large-seeded palms.

As tropical landscapes become increasingly human-dominated, conflicts between people and wildlife threaten ecological processes. Old World fruit bats such as flying foxes are especially susceptible to extinction risk because there is low interest in their conservation, particularly when they are considered pests. In order to arrest fruit bat declines, there is an urgent need to understand human-bat conflict and its implications. On a tropical island in Peninsular Malaysia, we conducted a questionnaire survey to investigate coexistence between people and the island flying fox (Pteropus hypomelanus). Among 119 respondents, knowledge of ecosystem services provided by flying foxes was extremely low. Most respondents held negative attitudes towards the bats, and older male locals were more likely to support killing them. This was also true for older owners of fruit trees who derived income from selling fruit, and experienced flying fox raids. Our results can be used to design appropriate interventions to support conservation efforts, and has important implications for managing conflicts between humans and synanthropic wildlife.

Forest fragmentation, reduced forest cover, and hunting pressure are the main threats affecting animal-mediated seed dispersal. However, their combined effects on seed dispersal rates have been simultaneously investigated only rarely, and never in Africa. We aimed to disentangle the effects of forest cover, hunting pressure, frugivore abundance, and fruit availability at the local and landscape scales on the seed dispersal rates of Staudtia kamerunensis (Myristicaceae). To estimate the percentages of seed dispersal failure (undispersed seeds), we quantitated fruit remains below fruiting trees distributed across five contrasting sites in a semi-natural forest-savanna mosaic in the Democratic Republic of Congo. We used statistical analyses accounting for spatial autocorrelation and found that forest cover in the surrounding landscape, hunting level, the associated abundance of dispersers, and fruit availability all had significant effects on the percentage of seed dispersal failure. The combination of high fruit availability and reduced abundance of seed dispersers could accelerate seed disperser satiation, causing the seed dispersal system to be saturated. Our study highlights how two major factors associated with anthropogenic activities, forest cover and hunting, affect seed dispersal by animals. These findings could have far-reaching implications for our understanding of tree-frugivore interactions and the conservation of tropical communities.

International audience

Large frugivores provide critical seed dispersal services for many plant species and their extirpation from forested ecosystems can cause compositional shifts in regenerating plant cohorts. Yet, we still poorly understand whether large seed-dispersers have complementary or redundant roles for forest regeneration. Here, to assess the functional complementarity of large-bodied frugivores in forest regeneration, we quantified the effects of varying abundance of hornbills, primates and the forest elephant on the density, species richness and the mean weighted seed length of animal-dispersed tree species among seedlings in five sites in a forest–savanna mosaic in D. R. Congo, while accounting for percentage forest cover and the local presence of fruiting trees. We found that the abundance of primates was positively associated with species richness of seedlings, while percentage forest cover was negatively associated (R2 = 0.19). The abundance of hornbills, the presence of elephants and percentage forest cover were positively associated with mean seed length of the regenerating cohort (R2 = 0.13). Spatially explicit analysis indicated that some additional processes have an important influence on these response indices. Primates would seem to have a preponderant role for maintaining relatively high species richness, while hornbills and elephant would seem to be predominantly responsible for the recruitment of large-seeded trees. Our results could indicate that these taxa of frugivores play complementary functional roles for forest regeneration. This suggests that the extirpation of one or more of these dispersers would likely not be functionally compensated for by the remaining taxa, hence possibly cascading into compositional shifts.

The interaction between granivorous scatterhoarding mammals and plants is a conditional mutualism: scatterhoarders consume seeds (acting as predators), but the movement of seed by scatterhoarders may contribute to dispersal (acting as mutualists). Understanding the ecological factors that shape this relationship is highly relevant in anthropogenically disturbed tropical forests where large-bodied frugivores are extirpated. In such forests, large-seeded trees that once depended on these frugivores for dispersal may now only have scatterhoarders as prospective dispersers. We studied Carapa oreophila (Meliaceae) in an Afromontane forest, to test the hypotheses that the proportion of seeds immediately consumed or hoarded (dispersed) would vary over a disturbance gradient. Temporal replication also afforded exploration of how habitat effects might vary with food availability. Using a Bayesian framework, we demonstrate that seeds were more likely to be hoarded in less disturbed forest, irrespective of temporal variation in food abundance. In contrast, forest disturbance only appeared to increase seed predation in temporal replicates that coincided with sustained food availability. These results highlight the potential variability in the dynamics between plants and scatterhoarders over fine temporal scales, elucidating possible ecological scenarios where scatterhoarders might act as mutualists (contributing positively to plant recruitment). Our study also fills important knowledge gaps about the importance of scatterhoarders as dispersers in tropical forests depleted of large-bodied frugivores, particularly in Africa where scatterhoarding mutualisms have not been extensively studied.

Fruit bats provide valuable pollination services to humans through a unique coevolutionary relationship with chiropterophilous plants. However, chiropterophily in the Old World and the pollination roles of large bats, such as flying foxes (Pteropus spp., Acerodon spp., Desmalopex spp.), are still poorly understood and require further elucidation. Efforts to protect these bats have been hampered by a lack of basic quantitative information on their role as ecosystem service providers. Here, we investigate the role of the locally endangered island flying fox Pteropus hypomelanus in the pollination ecology of durian (Durio zibethinus), an economically important crop in Southeast Asia.On Tioman Island, Peninsular Malaysia, we deployed 19 stations of paired infrared camera and video traps across varying heights at four individual flowering trees in a durian orchard. We detected at least nine species of animal visitors, but only bats had mutualistic interactions with durian flowers. There was a clear vertical stratification in the feeding niches of flying foxes and nectar bats, with flying foxes feeding at greater heights in the trees. Flying foxes had a positive effect on mature fruit set and therefore serve as important pollinators for durian trees. As such, semi-wild durian trees—particularly tall ones—may be dependent on flying foxes for enhancing reproductive success. Our study is the first to quantify the role of flying foxes in durian pollination, demonstrating that these giant fruit bats may have far more important ecological, evolutionary, and economic roles than previously thought. This has important implications and can aid efforts to promote flying fox conservation, especially in Southeast Asian countries.

The quantification of seed dispersal and predation processes has been gaining increased importance in the assessment of forest responses to anthropogenic disturbance, but also in developing an understanding of forest dynamics facing particular reproductive strategies. Seed removal rate is a reliable estimator of animal activities relating to these processes and can be quickly and easily estimated using a rapid assessment method (RAM) described by Lermyte and Forget (2009) and Boissier et al. (2014). This method consists in selecting trees reaching a given fruit crop in plots of interest and estimating, under each tree, the proportion of removed seeds in a single quadrat among the places having the highest crops; the proportion of removed seeds is obtained by enumeration of fruit scraps and intact fruits and estimation of their seed contents. The objective of this work is to evaluate the reliability of this method and to propose alternative estimation protocols (APs) in order to obtain an index of animal interaction with seeds. To do so, we estimated produced and removed seed numbers in up to 30 random 1 sq.m. quadrats under a total of 19 trees of Afzelia bipindensis , Dialium pachyphyllum/zenkeri and Xylopia staudtii . Secondly, we investigated the influence of tree size and fruit production on seed removal rate using a generalized linear mixed model. Thirdly, we used a generalized linear mixed model and a bootstrap procedure to test if RAM and APs are biased. Then, we compared their accuracy throughout their mean squared error, also obtained with a bootstrap approach. Despite its interesting accuracy, we showed that the RAM is positively biased. Removal rate was obviously influenced by canopy size and fruit production whereas the quadrats with higher fruit production have higher seed removal rates. Thus, trees with representative sizes and crops of the studied plots have to be sampled. Secondly, as an AP, random selection of several quadrats was found to be the best method. Based on these results, we recommend using the mean of three random quadrats per tree to estimate seed removal rate. It is an unbiased estimator, more accurate and more time efficient than the RAM. However, attention should be paid to select a proper quadrat size, in line with seed and fruit numbers, since the accuracy of the methods depends on these quantities. Such a choice could be made using a mean squared error criterion obtained from a preliminary intensive sampling of some specimens of the focal species.

As tropical landscapes become increasingly human-dominated, conflicts between people and wildlife threaten ecological processes. Old World fruit bats such as flying foxes are especially susceptible to extinction risk because there is low interest in their conservation, particularly when they are considered pests. In order to arrest fruit bat declines, there is an urgent need to understand human-bat conflict and its implications. On a tropical island in Peninsular Malaysia, we conducted a questionnaire survey to investigate coexistence between people and the island flying fox (Pteropus hypomelanus). Among 119 respondents, knowledge of ecosystem services provided by flying foxes was extremely low. Most respondents held negative attitudes towards the bats, and older male locals were more likely to support killing them. This was also true for older owners of fruit trees who derived income from selling fruit, and experienced flying fox raids. Our results can be used to design appropriate interventions to support conservation efforts, and has important implications for managing conflicts between humans and synanthropic wildlife. Electronic supplementary material The online version of this article (doi:10.1007/s10745-017-9905-6) contains supplementary material, which is available to authorized users.

Fruit bats provide valuable pollination services to humans through a unique coevolutionary relationship with chiropterophilous plants. However, chiropterophily in the Old World and the pollination roles of large bats, such as flying foxes (Pteropus spp., Acerodon spp., Desmalopex spp.), are still poorly understood and require further elucidation. Efforts to protect these bats have been hampered by a lack of basic quantitative information on their role as ecosystem service providers. Here, we investigate the role of the locally endangered island flying fox Pteropus hypomelanus in the pollination ecology of durian (Durio zibethinus), an economically important crop in Southeast Asia. On Tioman Island, Peninsular Malaysia, we deployed 19 stations of paired infrared camera and video traps across varying heights at four individual flowering trees in a durian orchard. We detected at least nine species of animal visitors, but only bats had mutualistic interactions with durian flowers. There was a clear vertical stratification in the feeding niches of flying foxes and nectar bats, with flying foxes feeding at greater heights in the trees. Flying foxes had a positive effect on mature fruit set and therefore serve as important pollinators for durian trees. As such, semi‐wild durian trees—particularly tall ones—may be dependent on flying foxes for enhancing reproductive success. Our study is the first to quantify the role of flying foxes in durian pollination, demonstrating that these giant fruit bats may have far more important ecological, evolutionary, and economic roles than previously thought. This has important implications and can aid efforts to promote flying fox conservation, especially in Southeast Asian countries.

Scatterhoarding by rodents, whereby seeds are collected and stored for later consumption, can result in seed dispersal. Seeds may be covered in litter on the forest floor (cached) or buried. This is particularly so in the Neotropics for large, nutritious seeds, and where primary dispersers are rare or missing. In African forests, contemporary anthropogenic pressures such as hunting, forest degradation, and fragmentation are contributing toward major declines in large frugivores, yet the potential for scatterhoarding to mitigate this loss is largely unknown. In this study, we used thread-marked seed to explore the balance between seed predation and dispersal by rodents in Afromontane forest. We studied two tree species in three habitats: (1) continuous forest; (2) continuous forest edge, and (3) small, degraded riparian forest patches. We found that seed removal rates were high and almost the same in all three habitats for both tree species, but that the predation/dispersal balance differed among habitats. In continuous forest, more seeds of each species were scatterhoarded than depredated, and rates of scatterhoarding differed between the two species. In all habitats, burying seeds up to 2 cm belowground was more common than caching. Distances seeds were moved was approximately five times greater in continuous forest than in forest edge or riparian patches. We found strong evidence to suggest that the African pouched rat, Cricetomys sp. nov was responsible for the scatterhoarding.

At the Nouragues field station (French Guiana), we studied the seed dispersal system of two sympatric tropical tree species that differ in seed size, Virola kwatae and V. michelii (Myristicaceae), to evaluate the degree of interaction between Virola species and their dispersers, and consistency in the fruit traits affecting seed removal rate. Only the spider monkey ( Ateles paniscus) and three species of ramphastid toucan dispersed the large (4.8g) V. kwatae seeds. These four animal species, as well as three smaller-bodied bird species, also dispersed the small V. michelii seeds (2.1g). Annual fecundity of both Virola species did not affect seed removal rate. However, variation in V. kwatae seed size within tree populations, and increased seed removal rate due to fruit selection on seed size, suggest a potential for an evolutionary response of seed size to selection by large-bodied frugivores in this species. In contrast, seed size did not affect V. michelii seed removal rate, and the interactions between V. michelii and its dispersers are interpreted to be too diffuse to result in strong selection on plant traits affecting seed removal rate. Because hunting pressure is greater on larger than on smaller frugivores, extinction of A. paniscus (the main large-bodied seed disperser of the study Virola) is likely to affect the long tail of dispersal kernel, thus decreasing recruitment away from fruiting adult trees.

Forested landscapes are increasingly affected by human activities, but little is known about the role of large endangered frugivores as seed dispersers in such ecosystems. We investigated the role played by the bonobo ( Pan paniscus ) in a human-altered forest-savanna mosaic in Democratic Republic of the Congo. The studied groups are part of a community-based conservation programme but live at the interface with human activities. We identified dispersed species via faecal analysis, classified them into a regeneration guild and a seed size category, determined the effect of gut transit on seed germination, and the habitat use of bonobos. Bonobos dispersed intact seeds of 77 species, 80.8% of which were large-seeded (≥ 10 mm long), of which few can be dispersed by sympatric frugivores. They dispersed a majority (49%) of shade-bearers that thrive in forest understory with limited amount of light, all of which were large-seeded. Transit had an overall positive effect on seed germination. Bonobos used various habitat types, showing preferences for understory with intermediate light availability and dominated by woody or herbaceous vegetation. This dispersal pattern probably enhances recruitment of shade-bearers, and we thus hypothesized that those species benefited from directed dispersal by bonobos. This threatened frugivore provides unique dispersal services and likely plays a paramount functional role in the regeneration of late successional forests in this mosaic landscape. Management plans should pay particular attention to the role of large and rare frugivores in human-dominated regions as their disappearance could disrupt forest succession to a climax state.

There is an urgent need to identify and understand the ecosystem services provided by threatened animal species such as flying foxes. The first step towards this is to obtain comprehensive data on their diet. However, the volant and nocturnal nature of flying foxes presents a challenging situation, and conventional microhistological approaches to studying their diet can be laborious and time-consuming, and provide incomplete information. We used Illumina Next-Generation Sequencing (NGS) as a novel, non-invasive method for analysing the diet of the island flying fox (Pteropus hypomelanus) on Tioman Island, Peninsular Malaysia. Through NGS analysis of flying fox droppings over eight months, we identified at least 29 Operationally Taxonomic Units comprising the diet of this giant pteropodid, spanning 19 genera and 18 different plant families, including one new family not previously recorded for pteropodid diet. NGS was just as successful as conventional microhistological analysis in detecting plant taxa from droppings, but also uncovered six additional plant taxa. The island flying fox’s diet appeared to be dominated by figs (Ficus sp.), which was the most abundant plant taxon detected in the droppings every single month. Our study has shown that NGS can add value to the conventional microhistological approach in identifying food plant species from flying fox droppings. However, accurate and detailed identification requires a comprehensive database of the relevant plant DNA, which may require collection of botanical specimens from the study site. Although this method cannot be used to quantify true abundance or proportion of plant species, nor plant parts consumed, it ultimately provides a very important first step towards identifying plant taxa in pteropodid diet.

There is an urgent need to identify and understand the ecosystem services of pollination and seed dispersal provided by threatened mammals such as flying foxes. The first step towards this is to obtain comprehensive data on their diet. However, the volant and nocturnal nature of bats presents a particularly challenging situation, and conventional microhistological approaches to studying their diet can be laborious and time-consuming, and provide incomplete information. We used Illumina Next-Generation Sequencing (NGS) as a novel, non-invasive method for analysing the diet of the island flying fox (Pteropus hypomelanus) on Tioman Island, Peninsular Malaysia. Through DNA metabarcoding of plants in flying fox droppings, using primers targeting the rbcL gene, we identified at least 29 Operationally Taxonomic Units (OTUs) comprising the diet of this giant pteropodid. OTU sequences matched at least four genera and 14 plant families from online reference databases based on a conservative Least Common Ancestor approach, and eight species from our site-specific plant reference collection. NGS was just as successful as conventional microhistological analysis in detecting plant taxa from droppings, but also uncovered six additional plant taxa. The island flying fox’s diet appeared to be dominated by figs (Ficus sp.), which was the most abundant plant taxon detected in the droppings every single month. Our study has shown that NGS can add value to the conventional microhistological approach in identifying food plant species from flying fox droppings. At this point in time, more accurate genus- and species-level identification of OTUs not only requires support from databases with more representative sequences of relevant plant DNA, but probably necessitates in situ collection of plant specimens to create a reference collection. Although this method cannot be used to quantify true abundance or proportion of plant species, nor plant parts consumed, it ultimately provides a very important first step towards identifying plant taxa and spatio-temporal patterns in flying fox diets.

International audience

Animal-mediated seed dispersal is important for sustaining biological diversity in forest ecosystems, particularly in the tropics. Forest fragmentation, hunting, and selective logging modify forests in myriad ways and their effects on animal-mediated seed dispersal have been examined in many case studies. However, the overall effects of different types of human disturbance on animal-mediated seed dispersal are still unknown. We identified 35 articles that provided 83 comparisons of animal-mediated seed dispersal between disturbed and undisturbed forests; all comparisons except one were conducted in tropical or subtropical ecosystems. We assessed the effects of forest fragmentation, hunting, and selective logging on seed dispersal of fleshy-fruited tree species. We carried out a meta-analysis to test whether forest fragmentation, hunting, and selective logging affected 3 components of animal-mediated seed dispersal: frugivore visitation rate, number of seeds removed, and distance of seed dispersal. Forest fragmentation, hunting, and selective logging did not affect visitation rate and were marginally associated with a reduction in seed-dispersal distance. Hunting and selective logging, but not fragmentation, were associated with a large reduction in the number of seeds removed. Fewer seeds of large-seeded than of small-seeded tree species were removed in hunted or selectively logged forests. A plausible explanation for the consistently negative effects of hunting and selective logging on large-seeded plant species is that large frugivores, as the predominant seed dispersers for large-seeded plant species, are the first animals to be extirpated from hunted or logged forests. The reduction in forest area after fragmentation appeared to have weaker effects on frugivore communities and animal-mediated seed dispersal than hunting and selective logging. The differential effects of hunting and selective logging on large- and small-seeded tree species underpinned case studies that showed disrupted plant-frugivore interactions could trigger a homogenization of seed traits in tree communities in hunted or logged tropical forests. ©2012 Society for Conservation Biology.

Negative density dependence (NDD) and environmental filtering (EF) shape community assembly, but their relative importance is poorly understood. Recent studies have shown that seedlings mortality risk is positively related to the phylogenetic relatedness of neighbours. However, natural enemies, whose depredations often cause NDD, respond to functional traits of hosts rather than phylogenetic relatedness per se. To understand the roles of NDD and EF in community assembly, we assessed the effects on seedling mortality of functional similarity, phylogenetic relatedness and stem density of neighbouring seedlings and adults in a species-rich tropical forest. Mortality risks increased for common species when their functional traits departed substantially from the neighbourhood mean, and for all species when surrounded by close relatives. This indicates that NDD affects community assembly more broadly than does EF, and leads to the tentative conclusion that natural enemies respond to phylogenetically correlated traits. Our results affirm the prominence of NDD in structuring species-rich communities.

Seed dispersal by rodents has been understudied in Africa. Based on seed-removal experiments, the presence of seeds in burrows and caches, cotyledon burial of seedlings, and images from camera traps, we provide evidence that rodents (Cricetomys kivuensis) remove and hoard large seeds of Carapa grandiflora in Nyungwe National Park, Rwanda.

Forest managers and harvesters of non-timber forest products (NTFPs) need a tool for rapid measurement of the impact of their activities on seed dispersal and tree recruitment. Such a tool could be used for a prospective eco-label which would ensure regeneration. We propose, and have used a new rapid assessment protocol to sample and evaluate the impact of any anthropogenic disturbance on seed dispersal and seedling recruitment of hard-tegument fruit species enclosing large seeds. We set up this protocol in French Guiana for a large-seeded scatter-hoarded tree species, Carapa surinamensis (andiroba), at three different forest sites affected by a variety of anthropogenic pressures, such as hunting and logging. Over a limited time we assessed: 1) dispersal failure: from late May to mid-June, the proportion of seeds remaining undispersed was estimated by sampling the number of seeds, seedlings and fruit husks in 25-m2subplots under the tree crown; 2) recruitment effectiveness: in September–October, seedlings were sampled on four 100-m2plots located 5–15 m from the tree base around the tree crown. Altogether, 77 trees were sampled, some 1–2 hours being spent beneath each tree, during a total 4–6 weeks in the field for each dispersal and recruitment sampling. We showed that: 1) seed dispersal is affected by hunting, this being significantly marked in the coastal area, which faces major anthropogenic pressures; 2) logging treatments affect seed dispersal and regeneration, on the average. However, canopy gaps due to sylvicultural treatments raise the life expectancy of seedlings.

The effect of forest disturbance on survival and secondary dispersal of an artificial seed shadow (N = 800) was studied at Brownsberg Natural Park, Suriname, South America. We scattered single seeds of the frugivore-dispersed tree Virola kwatae (Myristicaceae), simulating loose dispersal by frugivores, in undisturbed and disturbed secondary forest habitats. Seed survival rate aboveground was high (69%) within 2 wk and was negatively correlated with scatterhoarding rate by rodents, the latter being significantly lower in the undisturbed forest (9%) than in the disturbed forest (20%). Postdispersal seed predation by vertebrates was low (3%) and infestation of seeds by invertebrates was almost zero in all instances. Therefore, secondary seed dispersal by rodents in forest is not as critical for recruitment as observed among other bruchid-infested large-seeded species. Secondary seed dispersal by rodents may, however, facilitate seedling recruitment whether cached seeds experience greater survival than seeds remaining above ground surface.

Summary 1 Both spatial and temporal processes are assumed to play an important role in driving seedling dynamics. We assessed the magnitude of these two processes in a neotropical forest in French Guiana. We first quantified temporal changes in seedling community structure, then evaluated the relative importance of environmental heterogeneity and temporal fluctuations in seed arrival in determining seedling dynamics. 2 We monitored the seedling dynamics of 6244 seedlings by censusing 370 1-m 2 seedling plots in 160 stations over 20 months. At each station, we quantified environmental variability (light availability, soil resources, litter depth, topography), and measured temporal fluctuations in seed input by sampling seed arrival into seed traps located in each station. 3 Temporal changes in seedling density and diversity between four consecutive censuses were compared with those predicted by a neutral model assuming random recruitment and mortality. Seedling density fluctuations were considerably more variable over time than expected under the neutral assumption. Diversity changes showed less consistent results. For the two first census intervals, seedling diversity was more constant than under the neutral expectations. For the last census interval, seedling diversity was more variable than expected under neutrality. 4 Seedling recruitment, mortality and diversity of recruits were modelled against environmental variables and seed arrival. Sites with higher light availability and soil fertility had more diverse recruits ( P < 0.01) but lower seedling survival ( P < 0.05). Both density and diversity of local seed arrival had a positive effect, respectively, on density and diversity of recruited seedlings ( P < 0.05). 5 Our results show that temporal pulses in seedling community are mainly driven by large temporal fluctuations in seedling recruitment. Annual variation in seedfall and environmental filtering both contribute to explaining spatio-temporal variation in seedling dynamics to a large degree. Irrespective of species identity, tropical seedling communities are both seed- and establishment-limited. The temporal component of seed-limitation appears to be of critical relevance in the structuring of tropical seedling communities.

Made available in DSpace on 2018-12-11T16:40:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-11-01 Species showing mast seeding synchronously produce large amounts of fruits during some scattered years. This massive crop has been hypothesized to improve dispersal effectiveness by a satiation of seed predators, but the consequences for seed dispersers have barely been studied in the tropics. We tested the hypothesis that masting resulted in satiation of frugivorous dispersers using the study case of two Manilkara species growing in an Amazonian forest in French Guiana. Seed dispersal was estimated by means of seed traps in two forest types during a 10-y monitoring. Manilkara huberi and M. bidentata showed three fruiting events in a time span of 10 y (in 2001, 2006 and 2010). Estimates of seed dispersal from 2001 and 2010 showed that satiation of frugivores only occurred in the year with the largest crop of Manilkara (2010) and in the habitat where the diversity of primate-dispersed species retrieved in seed traps was the highest (Grand Plateau, with clay soils), while fruit consumers did not seem to be satiated in other instances. Spatio-temporal variability of seed production and the community-crop context are therefore affecting satiation of frugivores during masting events. CNRS-MNHN Museúm National d'Histoire Naturelle Département d'Écologie et Gestion de la Biodiversité, 1 Av. du Petit Château Departamento de Botânica Plant Phenology and Seed Dispersal Research Group Universidade Estadual Paulista (UNESP), Avenida 24-A CNRS Guyane USR 3456, 2 rue Gustave Charlery Departamento de Botânica Plant Phenology and Seed Dispersal Research Group Universidade Estadual Paulista (UNESP), Avenida 24-A

192 pages; National audience; Les événements écologiques survenus ces dernières années, notamment en raison des changements globaux, et du réchauffement climatique en particulier, ont fait prendre conscience à l'opinion publique des menaces qui planent sur les zones tropicales. Et les sciences, dans une nouvelle approche transversale et interdisciplinaire, se penchent aujourd'hui sur cette écologie unique qui abrite des écosystèmes d'une grande complexité. En effet, l'équilibre de notre planète repose en partie sur ces environnements fragiles où évolue le plus grand nombre d'espèces en densité et en diversité. Cette biodiversité et la gestion des ressources associées apparaissent comme l'un des enjeux écologiques majeurs du XXIe siècle. Des spécialistes de toutes les disciplines, issus des laboratoires du CNRS ou associés, présentent les travaux menés et tracent les voies prospectives de recherche pour les années à venir. Ils nous font découvrir les spécificités de ces espaces tropicaux, les mécanismes adaptatifs impressionnants développés par les organismes qui y vivent et le fonctionnement de ces systèmes écologiques remarquables. Ce livre nous plonge dans le monde fascinant de la faune et la flore tropicales, encore largement méconnues, et nous invite à penser ce grand défi auquel les sociétés devront faire face : la conciliation du bien-être humain et l'utilisation durable des ressources naturelles.

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1- We examined among- and within-species effects of seed mass for seedling establishment from seed to 5 years of age in a field experiment at Paracou, French Guiana. 2- Six seeds of each of eight species were weighed and planted into each of 120 plots (1 m2) throughout closed-canopy forest along 12 100-m transects in 1998. 3- We described the microhabitat of each planting site using principal components derived from measurements of light availability, soil moisture, carbon and nitrogen content, and soil phosphorus availability. Although both survival and relative growth rate (RGR) increased with increasing light availability, no other microhabitat variable significantly affected seedling performance. Nor did the magnitude of microhabitat effects on survival or RGR differ among species. 4- Larger-seeded species were more likely to survive from germination to 1 year as well as from 1 to 5 years of age. RGR for seedling height during the first year post-germination was not related to seed mass, but smaller-seeded species did grow slightly faster thereafter. Path analyses revealed that correlations between seed mass and performance were explained in part because larger seeds produced larger initial seedlings, which tended to survive better but grow more slowly. 5- We also analysed within-species effects of seed mass for the larger-seeded Eperua grandiflora and Vouacapoua americana (both Caesalpiniaceae). Larger seeds produced larger seedlings in both species, but larger seeds survived better only for Eperua. Larger seedlings grew more slowly in both species, but did not offset the early (Eperua) and later (Vouacapoua) positive direct effects of seed mass on RGR that may represent contrasting strategies for reserve deployment. 6- Our results demonstrate that seed size influences performance within and among species in part because of indirect effects of initial seedling size. However, we suggest that traits tightly correlated with seed mass at the species level, such as specific leaf area, leaf longevity and photosynthetic capacity, may also contribute to interspecific performance differences.

Forest fragmentation results in the creation of edge habitats, which can be responsible for large modifications in community dynamics (Murcia 1995, Saunders et al. 1991). Plant recruitment along edges is favoured for early successional species but is limited for core forest species (Fox et al. 1997, Williams-Linera 1990). Because the former generally produce large quantities of small seeds while the latter produce fewer large seeds (Hammond & Brown 1995), seed resource availability along the edge is biased in favour of smaller seeds. Such seeds are more likely to attract small rodents than large scatterhoarding species (Adler 1998, Forget et al. 1998). Moreover, the density and activity of forest animals in edge habitats can also be altered as a consequence of their specific responses to habitat changes, varying from edge avoidance to edge preference (Bowers & Dooley 1993, Goosem 2000). These changes in seed resource availability and rodent communities can have cascading effects on plant–rodent interactions in edge habitats and post-dispersal seed predation processes (Holl & Lulow 1997).