THE EFFECTS OF HABITAT DISTURBANCE ON TROPICAL HERPETOFAUNA AND SMALL MAMMAL DIVERSITY

Gold-ringed Cat Snake (Boiga dendrophila)             Photo: G. Gillespie 

Conservation and sustainable development in South-East Asia are critically dependent on:

• The identification of important areas where limited conservation resources can be focused.
• The identification of key threatening processes.
• The development of ways to manage these threatening processes.

The relationship between rainforest clearing and the loss of large mammal/bird species may be obvious. However, much of the remaining forest in South-East Asia is subject to other, perhaps less destructive, anthropogenic disturbance processes (such as rattan harvesting and selective logging).

These disturbed forest habitats are increasingly important for biodiversity conservation. A greater understanding of the relationships between habitat modification and species/community assemblages is therefore necessary to refine conservation priorities and so develop sound conservation management practices.

In the past, wildlife conservation efforts have often focused on larger charismatic wildlife species. In tropical rainforests, however, reptiles and amphibians may comprise the bulk of terrestrial vertebrate diversity. Unfortunately, the habitat requirements and responses to habitat modification are poorly understood for many of these species in South-East Asia.

The complex geological origins and geographical position of the island of Sulawesi have resulted in a distinctive mixture of Australasian and Asian floral and faunal elements, with high levels of endemism across all vertebrate groups. Despite the island's biogeographical significance, little is known about the biology (let alone the conservation status) of most species occurring in Sulawesi.

Dr Graeme Gillespie, from Zoos Victoria, is leading a research project to examine the herpetofauna (reptile and amphibian) and small mammal communities across a range of habitats in south-east Sulawesi, including undisturbed and human-modified habitats.

AIMS

This project has the following specific objectives:

1. Undertake an inventory of the vertebrate species occurring in the region.
2. Describe new species located.
3. Examine factors that influence community composition across a gradient of disturbed and undisturbed habitats.
4. Examine temporal variation in community composition in response to on-going disturbance and climatic changes.
5. Investigate the impact of specific threatening processes on targeted species. 
6. Undertake capacity-building and training of local (Indonesian) personnel.

METHODS

The study site is located on Buton, an island off the south-east coast of Sulawesi. Seventy-six sampling sites have been established throughout the forest along a disturbance gradient, from sites close to human settlements (relatively disturbed) to sites distant from human settlements (relatively pristine).

Transects along streams have also been established through out this area to study the stream-breeding frog populations.

Each year a subset of these sites is sampled using a range of techniques such as pitfall trapping and active searches during the day and night. All species of vertebrates are recorded and the structural composition of the habitat at each site is measured.

RESULTS

So far, seven new reptile and one new frog species have been discovered; three of these species have now been formally described.

The distribution and habitat relationships of 73 reptile, 12 frog and five small mammal species have been documented.

The relationships between habitat disturbance and community organisation are currently being analysed.

The impacts of human hunting pressure on the ecology and behaviour of the large frog species Limnonectes grunniens are currently being analysed.

FOR MORE INFORMATION

- on this project - click here to email Dr Graeme Gillespie (Principal Investigator)