Onja H. Razafindratsima

Assessing the impacts of nonrandom seed dispersal by multiple frugivore partners on plant recruitment

Directed dispersal is defined as enhanced dispersal of seeds into suitable microhabitats, resulting in higher recruitment than if seeds were dispersed randomly. While this constitutes one of the main explanations for the adaptive value of frugivore-mediated seed dispersal, the generality of this advantage has received little study, particularly when multiple dispersers are involved. We used probability recruitment models of a long-lived rainforest tree in Madagascar to compare recruitment success under dispersal by multiple frugivores, no dispersal, and random dispersal. Models were parameterized using a three-year recruitment experiment and observational data of dispersal events by three frugivorous lemur species that commonly disperse its seeds. Frugivore-mediated seed dispersal was nonrandom with respect to canopy cover and increased modeled per-seed sapling recruitment fourfold compared to no dispersal. Seeds dispersed by one frugivore, Eulemur rubriventer, had higher modeled recruitment probability than seeds dispersed randomly. However, as a group, our models suggest that seeds dispersed by lemurs would have lower recruitment than if dispersal were random. Results demonstrate the importance of evaluating the contribution of multiple frugivores to plant recruitment for understanding plant population dynamics and the ecological and evolutionary significance of seed dispersal.

Patterns of movement and seed dispersal by three lemur species

We combined data on gut‐passage times, feeding, and movement to explore the patterns of seed dispersal by Eulemur rubriventer, Eulemur rufrifrons, and Varecia variegata editorum lemurs in Ranomafana National Park, Madagascar. These lemur species deposited less than half of their consumed seeds >100 m away from conspecific trees (40–50%). Long‐distance dispersal (>500 m) was rare and average dispersal distances were short relative to those reported of similar‐sized haplorrhine primates. The three lemur species showed no significant differences in mean seed‐dispersal distances. However, they differed in the shape of their frequency distributions of seed‐dispersal distances as a result of differences in how they moved through their habitats. The short distances of seed dispersal we observed and the depauperate frugivorous fauna in Madagascar suggest seed‐dispersal may be more limited than in other tropical forests with important implications for plant‐community dynamics, biodiversity maintenance, and restoration efforts in Madagascar. Am. J. Primatol. 76:84–96, 2014.

Body size and sexual size dimorphism in primates: influence of climate and net primary productivity.

Understanding the evolution of body size and sexual size dimorphism has been a longstanding goal in evolutionary biology. Previous work has shown that environmental stress can constrain male‐biased sexual size dimorphism at the population level, but we know little about how this might translate to geographical patterns of body size and sexual size dimorphism at the species level. Environmental constraints due to a highly seasonal, resource‐poor and/or variable environment have often been cited to explain the unusual lack of sexual size dimorphism among Madagascars diverse and numerous primate taxa; however, empirical tests of this hypothesis are lacking. Using a phylogenetic approach and a geographical information system platform, we explored the role of seasonality, interannual variability and annual measures of temperature and rainfall, and net primary productivity on patterns of body size and sexual size dimorphism across 130 species of primates. Phylogenetically controlled comparisons showed no support for a role of environmental constraints in moderating sexual size dimorphism at the interspecific level, despite significant associations of environmental variables with body mass. Results suggest that the focus of discussions that have dominated in the last two decades regarding the role of environmental constraints in driving patterns of monomorphism of Madagascars lemurs should be reconsidered; however, the conundrum remains.

Co‐fruiting plant species share similar fruit and seed traits while phylogenetic patterns vary through time

Summary 1.Co-fruiting plant species are subject to a variety of biotic and abiotic processes that may influence patterns of fruiting phenology and the functional and phylogenetic diversity of co-fruiting taxa in a community. Understanding the seasonal patterns of functional and phylogenetic diversity of fruiting in a community will shed new light on potential mechanisms structuring plant communities. 2.Using rainforest trees in south-eastern Madagascar as our system, we predicted there would be clustering of fruit and seed traits and phylogenetic relationships among co-fruiting species because plants are vying for seed dispersal services from a limited set of generalist frugivore taxa. We also predicted that seasonal variations in rainfall would mediate fluctuations in functional trait and phylogenetic diversity of co-fruiting assemblages. 3.Despite fluctuating patterns in their functional trait diversity over time, co-fruiting assemblages displayed consistent clustering of fruit/seed traits across time. Phylogenetic diversity was not clustered overall, but fluctuated non-randomly, in time between clustered and overdispersed, such that strong shifts in rainfall were associated with the co-fruiting of more closely related species. 4.Synthesis: We suggest that it may be more beneficial for co-fruiting plant species to share similar fruit and seed traits than to diversify traits, when they rely on a comparatively small set of generalist frugivorous taxa for seed dispersal. Results also demonstrate that rainfall-driven environmental filtering may cause seasonal fluctuations in the phylogenetic patterns of phenology in a community. Results highlight the importance of a temporal context in examining structural patterns of communities. This article is protected by copyright. All rights reserved.

MADA: Malagasy Animal trait Data Archive

Species are characterized by their behavioral, physiological, and ecological attributes, which determine their role in ecosystems. In turn, ecosystems and their functions are defined by the species that inhabit them. Thus, evaluating the functional diversity and distributions of species is of utmost importance to studies of biogeography, community ecology, macroevolution, and conservation. The functional diversity of species are determined by traits such as diet, foraging strata, trophic level, activity cycle, litter size, generation length, habitat breadth, and body mass. While there has been a recent growth of information regarding the vertebrate taxa of Madagascar, this information is not always easy to access (non-digitized), and is often fragmented by taxon, location, trait, or combinations thereof. Here, we present the Malagasy Animal trait Data Archive (MADA), a compilation of these and other functional traits, representing the ecological and geographical diversity of all 214 extant mammal and 242 bird species of Madagascar. Data were collected from extensive literature reviews. This Archive is currently limited by select cases of missing data, errors, and uncertainty in the literature; however, it represents the most comprehensive collection of functional trait data of Malagasy mammals and birds to date. The structure of the database allows for different levels of information (and specificity) in each entry and organization by taxon, range, bioclimate, and trait. MADA will be continuously updated as new data become available. Potential uses of MADA include ecological research on the trait or trophic structure of communities, inquiries regarding the mechanisms of community assembly, comparative studies of functionally (dis)similar species, and conservation efforts concerned with the loss of ecosystem function. Madagascar is simultaneously home to one of the most exclusive, diverse, and endangered faunas of the world, making MADA a uniquely valuable resource for biodiversity science and conservation. No copyright restrictions are associated with this dataset. We would appreciate that researchers cite this paper if using all or part of the datasets.

Edge effects on components of diversity and above‐ground biomass in a tropical rainforest

Edge effects are among the most significant consequences of forest fragmentation. Therefore, understanding the impacts of edge creation on biodiversity is crucial for forest management and biological conservation. In this study, we used trait‐based and phylogenetic approaches to examine the effects of fragmentation on components of diversity and above‐ground biomass of rainforest tree communities in Madagascar in forest edge vs. interior habitats. Tree communities in forest edges showed lower phylogenetic diversity relative to those in interior habitats, suggesting that some clades may be more vulnerable to environmental filtering than others. Functional diversity was also significantly lower on the edge for productivity traits, but not for dispersal traits. Tree communities in the forest edge showed higher divergence of dispersal traits and lower divergence in productivity traits than expected, while functional diversity in interior forest did not differ from random expectations. This suggests that separate mechanisms affect productivity traits vs. dispersal traits in edge habitats. There was no significant difference in above‐ground biomass between edge and interior habitats, suggesting that edge effects have not yet negatively influenced the forests potential for carbon storage. However, these changes may not have occurred yet, given the slow turnover of tree communities. Synthesis and applications. Our results highlight the role of edge effects in the erosion of functional and phylogenetic diversity of highly diverse tree communities. While above‐ground biomass did not appear to be affected by forest edge in our study, we suggest long‐term monitoring of forests for potential changes in ecosystem functioning. These findings also indicate the need to reduce edge creation and buffer existing edges for holistic biodiversity conservation.

Decision complacency and conservation planning: Decision Complacency

Article impact statement: : Conservation planners must use systematic decision?making tools and evidence to guide their decisions.

Anthropogenic threats can have cascading homogenizing effects on the phylogenetic and functional diversity of tropical ecosystems

Determining the mechanisms that underlie species distributions and assemblages is necessary to effectively preserve biodiversity. This cannot be accomplished by examining a single taxonomic group, as communities comprise a plethora of interactions across species and trophic levels. Here, we examine the patterns and relationships among plant, mammal, and bird diversity in Madagascar, a hotspot of biodiversity and endemism, across taxonomic, phylogenetic, and functional axes. We found that plant community diversity and structure are shaped by geography and climate, and have significant influences on the taxonomic, phylogenetic and functional diversity of mammals and birds. Patterns of primate diversity, in particular, were strongly correlated with patterns of plant diversity. Furthermore, our findings suggest that plant and animal communities could become more phylogenetically and functionally clustered in the future, leading to homogenization of the flora and fauna. These results underscore the importance and need of multi-taxon approaches to conservation, given that even small threats to plant diversity can have significant cascading effects on mammalian and avian community diversity, structure, and function.

Seed Dispersal by Multiple Frugivores

We investigated the advantages of directed dispersal by multiple frugivores to plant recruitment. We used probability recruitment models of a long-lived rain forest tree in Madagascar, to compare recruitment success with dispersal by multiple frugivorous lemurs, with no dispersal, and random dispersal. Our results show that frugivore-mediated seed dispersal was nonrandom with respect to canopy cover and increased modeled per-seed sapling recruitment fourfold compared to no dispersal. Seeds dispersed by one frugivore, Eulemur rubriventer, had higher modeled recruitment probability than seeds dispersed randomly. However, as a group, our models suggest that seeds dispersed by lemurs would have lower recruitment than if dispersal were random. Onja H. Razafindratsima and Amy E. Dunham