Decadal Change in the Kerangas Avifaunal Complex in Universiti Brunei Darussalam, Brunei Darussalam

Abstract

An urbanized forest habitat is often subjected to spatial and temporal changes in the avian assemblage that inhabits it. The Universiti Brunei Darussalam (UBD) campus built on a coastal kerangas forest (tropical heath) in 1985, is a case in point. This forest type is vulnerable to fires and extensive areas have been burnt over the years and parts of the chosen site for the campus too have been affected. Four avian surveys to study the extent of change in the species richness, were carried out in this site in 1989-1991, 1998-2000, 2006-2007 and 2019-2020. When comparing species richness between years and before and after the building of the campus, there was a significant decline after the campus was built. Three kinds of forests were surveyed - undisturbed contiguous forests, fragmented kerangas sites and the UBD kerangas. To understand the significance of this change, the species richness in undisturbed contiguous sites was five times greater than in the fragmented sites, while that in UBD was twice greater than in the fragmented sites. Furthermore, contiguous sites showed a high dissimilarity from the fragmented disturbed sites. Though UBD was grouped together with the fragmented sites it showed a high dissimilarity from them. As expected, species richness increases with site area, the large contiguous kerangas sites harbouring more species than the small fragmented disturbed sites. A scrutiny of the avian species assemblage shows a large shift from the presence of kerangas forest species before building of the campus to habitat generalists especially granivores at present, characteristic of an urbanized forest habitat.