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Department of Social Sciences
Faculty of Humanities and Social Sciences
Headington Campus, Gibbs Building
I am a co-director of the Borneo Nature Foundation (www.borneonaturefoundation.org) and BRINCC (Borneo River Initiative for Nature Conservation and Communities www.brinccborneo.org). I am an Associate Lecturer on the MSc in Primate Conservation since 2010. I have carried out research in South East Asia since 1997 and Indonesia since 2002. I am leading a long-term study of gibbon behaviour, ecology and socio-ecology in peat-swamp forests as well as conducting a detailed study of gibbon population density and distribution across Indonesian Borneo (Hylobates albibarbis, H. muelleri and H. funereus). I initiated the first long-term, detailed study of felid and large mammal biodiversity and conservation in the area, and across Indonesian Borneo with a focus on the Sunda clouded leopard (Neofelis diardi). I am overseeing the continuation of the first long-term study of red langurs (Presbytis rubicunda) in peat-swamp forest. I work with several IUCN Specialist groups advising on and leading conservation policy and I am the Vice Chair of the IUCN Section on Small Apes http://www.gibbons.asia/. I have also carried out surveys on flying fox hunting and abundance, and is interested in how anthropogenic factors affect biodiversity in peat-swamp forests
U20146 Becoming and Independent Researcher
P20105 Captive Management
I am interested in captive management of primates and other mammals, especially in rescue centres in situ and contribute to ongoing research into the best approach to rehabilitation, reintroduction and translocation of apes.
Borneo Nature Foundation
IUCN Section on Small Apes
Gibbons are highly territorial and have two key areas within these territories. The core area in which we find all sleeping trees and the trees from which the gibbons duet and the wider home range (HR) which has varying levels of overlap with neighbouring gibbon groups. The core area is strenously defended, with the wider HR being more of a shared area for neighbouring groups. We present ranging and movement data on four wild gibbon groups from January 2010 to July 2018. Global Positioning System (GPS) data were collected every 5 mins on habitauted groups in Sebangau, Central Kalimantan, Indonesia resulting in 35,521 waypoints. Gibbon home- and corerange sizes were calculated using 95%, and 50%, volume contours of kernel density estimates. Home-ranges ranged from 58.74–147.75 ha with a mean of 95.7 ± SD 37.75 ha, the highest of comparable Hylobates species. Core-range size ranged from 20.7–51.31 ha with a mean size of 31.7 ± SD 13.76 ha. Gibbons had consistant site fidelity for their home- and core ranges; percentage overlap ranged from 4.3 23.97% with a mean 16.5 ± SD 8.65% overlap in home-range area. Core ranges did not overlap with the exception of two groups, in which a 0.64 ha (2.69%) overlap occurred. Unsurprisingly forest loss from fire does affect the location of the HR of the impacted group, but does not appear to affect adjacent groups, though more data are needed on this. Understanding the complex use of space of these territorial animals is important in assessing both carrying capacity for wild populations and understanding how reintroduced gibbon pairs will establish their core and HR.
Tropical forests are globally important for both biodiversity conservation and the production of economically valuable wood products. To deliver both simultaneously, two contrasting approaches have been suggested: one partitions forests (sparing); the other integrates both objectives in the same location (sharing). To date, the ‘sparing or sharing’ debate has focused on agricultural landscapes, with scant attention paid to forest management. We explore the delivery of biodiversity and wood products in a continuum of sparing-to-sharing scenarios, using spatial optimization with set economic returns in East Kalimantan, Indonesia—a biodiversity hotspot. We found that neither sparing nor sharing extremes are optimal, although the greatest conservation value was attained towards the sparing end of the continuum. Critically, improved management strategies, such as reduced-impact logging, provided larger conservation gains than altering the balance between sparing and sharing, particularly for endangered species. Ultimately, debating sparing versus sharing has limited value while larger gains remain from improving forest management.
We develop a time budget model for the hylobatid family with the aim of assessing the extent to which their contemporary and historical biogeographic distributions might be explained by ecological constraints. The model uses local climate to predict time budgets, and from this the limiting size of social group that animals could manage at a given location. The model predicts maximum group sizes that vary between 3-15 within the taxon’s current distribution, indicating that the combination of their dietary and locomotor styles with the kinds of habitats they inhabit radically constrain group size. Beyond the edges of their current distribution, sustainable group size rapidly tends to zero, although if they had been able to bypass some of these areas, they would have found very suitable habitats in southern India and across the Wallace Line. While travel time would be a major constraint on group size at larger group sizes, as it is in great apes, the main factor limiting the gibbon’s current distribution is the time they need to spend resting that is imposed on them by the environment. The model also indicates that gibbons would not now be able to survive in regions of central and southern China where they are known to have occurred within historical times, perhaps suggesting that historical climate change following the Little Ice Age of the C18th made these regions uninhabitable for them. Finally our results indicate that gibbons have the ecological capacity to live in larger groups than they do, making it unlikely that their adoption of monogamy reflects purely ecological constraints.
Using direct observations and camera traps at eight sites across Indonesian Borneo we show how red langurs (Presbytis rubicunda) are more terrestrial than previously believed, regularly coming to the ground. This unusual behavior has been found at six of the eight sites surveyed. We find that red langurs come to the ground more frequently in disturbed forests, specifically ones which have been impacted by logging, fire, and hunting, though more data are needed to confirm this as a direct correlation. We also found a trend towards decreased ground use with increased elevation of the habitat. When on the ground, red langurs are predominantly engaged in feeding (50% direct observations, 61% camera traps) and traveling (29% direct observations, 13% camera traps). Red langurs are found on the ground throughout the day, at similar times to activity periods of the apex predator, the Sunda clouded leopard (Neofelis diardi). We suggest that ground use by red langurs could be an adaptation to disturbed forest to exploit additional food sources and to facilitate travel.