The Orangutan Tropical Peatland Project

Palangkaraya, Indonesia

The Orangutan Tropical Peatland Project

Palangkaraya, Indonesia
Time filter
Source Type

Beaudrot L.,University of California at Davis | Struebig M.J.,University of Kent | Struebig M.J.,Queen Mary, University of London | Meijaard E.,People and Nature Consulting International | And 5 more authors.
American Journal of Primatology | Year: 2013

For several decades, primatologists have been interested in understanding how sympatric primate species are able to coexist. Most of our understanding of primate community ecology derives from the assumption that these animals interact predominantly with other primates. In this study, we investigate to what extent multiple community assembly hypotheses consistent with this assumption are supported when tested with communities of primates in isolation versus with communities of primates, birds, bats, and squirrels together. We focus on vertebrate communities on the island of Borneo, where we examine the determinants of presence or absence of species, and how these communities are structured. We test for checkerboard distributions, guild proportionality, and Fox's assembly rule for favored states, and predict that statistical signals reflecting interactions between ecologically similar species will be stronger when nonprimate taxa are included in analyses. We found strong support for checkerboard distributions in several communities, particularly when taxonomic groups were combined, and after controlling for habitat effects. We found evidence of guild proportionality in some communities, but did not find significant support for Fox's assembly rule in any of the communities examined. These results demonstrate the presence of vertebrate community structure that is ecologically determined rather than randomly generated, which is a finding consistent with the interpretation that interactions within and between these taxonomic groups may have shaped species composition in these communities. This research highlights the importance of considering the broader vertebrate communities with which primates co-occur, and so we urge primatologists to explicitly consider nonprimate taxa in the study of primate ecology. © 2012 Wiley Periodicals, Inc.

Beaudrot L.,University of California at Davis | Struebig M.J.,University of Kent | Struebig M.J.,Queen Mary, University of London | Meijaard E.,People and Nature Consulting International | And 4 more authors.
Oecologia | Year: 2013

Assessing the importance of deterministic processes in structuring ecological communities is a central focus of community ecology. Typically, community ecologists study a single taxonomic group, which precludes detection of potentially important biotic interactions between distantly related species, and inherently assumes competition is strongest between closely related species. We examined distribution patterns of vertebrate species across the island of Borneo in Southeast Asia to assess the extent to which inter-specific competition may have shaped ecological communities on the island and whether the intensity of inter-specific competition in present-day communities varies as a function of evolutionary relatedness. We investigated the relative extent of competition within and between species of primates, birds, bats and squirrels using species presence-absence and attribute data compiled for 21 forested sites across Borneo. We calculated for each species pair the checkerboard unit value (CU), a statistic that is often interpreted as indicating the importance of interspecific competition. The percentage of species pairs with significant CUs was lowest in within-taxon comparisons. Moreover, for invertebrate-eating species the percentage of significantly checkerboarded species pairs was highest in comparisons between primates and other taxa, particularly birds and squirrels. Our results are consistent with the interpretation that competitive interactions between distantly related species may have shaped the distribution of species and thus the composition of Bornean vertebrate communities. This research highlights the importance of taking into account the broad mammalian and avian communities in which species occur for understanding the factors that structure biodiversity. © 2013 Springer-Verlag Berlin Heidelberg.

PubMed | National University of Indonesia, Center for the International Cooperation in Sustainable Management of Tropical Peatlands, University of Zürich, University of Palangka Raya and 3 more.
Type: Journal Article | Journal: PloS one | Year: 2015

Bottom-up regulatory factors have been proposed to exert a strong influence on mammalian population density. Studies relating habitat quality to population density have typically made comparisons among distant species or communities without considering variation in food quality among localities. We compared dietary nutritional quality of two Bornean orangutan populations with differing population densities in peatland habitats, Tuanan and Sabangau, separated by 63 km. We hypothesized that because Tuanan is alluvial, the plant species included in the orangutan diet would be of higher nutritional quality compared to Sabangau, resulting in higher daily caloric intake in Tuanan. We also predicted that forest productivity would be greater in Tuanan compared to Sabangau. In support of these hypotheses, the overall quality of the diet and the quality of matched dietary items were higher in Tuanan, resulting in higher daily caloric intake compared to Sabangau. These differences in dietary nutritional quality may provide insights into why orangutan population density is almost two times greater in Tuanan compared to Sabangau, in agreement with a potentially important influence of diet quality on primate population density.

Marchant N.C.,The Orangutan Tropical Peatland Project | Purwanto A.,The Orangutan Tropical Peatland Project | Purwanto A.,University of Palangka Raya | Harsanto F.A.,The Orangutan Tropical Peatland Project | And 6 more authors.
Ecological Entomology | Year: 2015

1. Tropical fruit-feeding Nymphalidae butterflies are widely used in research, monitoring, and conservation projects, but to date a key aspect of their behaviour-dispersal-remains poorly understood. They have anecdotally been described as 'relatively sedentary' based on movement vectors from mark-recapture studies, but this may be inaccurate because plot-based studies in small sampling areas often underrepresent long-distance movements. 2. Based on data from a peat-swamp forest in Borneo, it was found that these butterflies may be much more mobile than previously thought, as they frequently moved distances of 1-2km between sampling plots. Median daily movements were approximately 200-250m, and over lifespans of one or more months these movements may sum to total life-time dispersals of several kilometres. 3. Recapture rates for long-distance movements between sampling plots were between 28.2% and 41.6% of the re-encounter rates that would be predicted by a random-walk approximation/Brownian motion (without accounting for survival rates), supporting the hypothesis that it is a suitable model of dispersal in this group, although further research is needed to confirm this. 4. There was no evidence that butterflies occupied permanent home ranges, and it is suggested that a permanent home range or territorial behaviour would be maladaptive in this group. Pseudo-replication caused by 'trap-happy' behaviour was not found to be widespread, and some recommendations are provided regarding the treatment of recapture data in trap-based studies. 5. These findings substantially increase the spatial parameters for future research and conservation projects in this group and are also applicable to theoretical modelling studies. An abstract for this article in Bahasa Indonesia is included in the online supporting information File S1. © 2015 The Royal Entomological Society.

Loading The Orangutan Tropical Peatland Project collaborators
Loading The Orangutan Tropical Peatland Project collaborators