Fragment size, edge effects, and anthropogenic factors influences on the movement, distribution of proboscis monkeys (Nasalis larvatus) in the Kinabatangan Floodplain, Sabah


PhD Researcher: Danica Stark

Institution: Cardiff University

Supervisors: Benoît Goossens, Ian Vaughan

Status: Completed

Responses to habitat loss and forest fragmentation are species-specific and need to be examined as such. Habitat loss and fragmentation are challenging wildlife, and species with large home ranges or that are habitat specialists are particularly vulnerable to this. Although there have been many studies examining primate responses to habitat loss and fragmentation, they have focused mainly on abundance and density. Home ranging and other detailed ecological responses have not played a large role in these discussions but are crucial given the functional roles primates play in their ecosystems. It is likely that different primate species will respond differently to habitat loss or other anthropogenic activities according to differences in their ecological traits.

Research Questions:

  • How large are proboscis monkey home ranges, and how is this estimate affected by the method of analysis?
  • Is there a simple, low-cost, yet ecologically meaningful way of collecting data/mapping in remote/difficult areas using drone data to map habitats?
  • Do forest characteristics impact the range size, intensity rates or recursion rates? Protected forest vs unprotected forest.
  • What is the short-term variation in habitat use for the foraging or movement ecology of proboscis monkeys?

Satellite collars were put on proboscis monkeys for the first time ever for this species. As proboscis monkeys tend to live in swampy, wet areas, it is often difficult to track them by foot continuously, particularly in the wet season when the forest can flood. Furthermore, due to the difficulties in habituating and tracking a primate group, previous studies have only been able to track one group at a time and are limited by factors such as weather, which can prevent fieldwork. By using GPS collars, ten groups were tracked across different seasons, with multiple groups tracked simultaneously. Drones (Unmanned aerial vehicles) were used to map the home range of the proboscis monkeys to produce high-resolution and ecologically meaningful habitat maps.

The results produced from the project were used in developing the State Action Plan for the management plan of proboscis monkeys in Sabah, illustrating the amount of forest necessary for the survival of the species in terms of space available, food resources and connectivity to allow for movement between groups/sub-populations.

Proboscis monkey collaring©DGFC