RESPONSES OF BABBLERS (TIMALIIDAE) TO THE FOREST EDGE—INTERIOR GRADIENT IN AN ISOLATED TROPICAL RAINFOREST IN PENINSULAR MALAYSIA

The understanding of bird community responses, especially Timaliidae family, to tropical forest edge—interior gradient is limited. In this study, the point-count sampling method was used to determine community composition, abundance and density of babblers along the edge—interior gradient in Ayer Hitam Forest Reserve, Peninsular Malaysia. Environmental variables were measured within a 25 m radius of each point. Babbler species richness and diversity were positively correlated with humidity, distance from edge and the number of palm trees. There was a clear structured gradient in babbler species composition across edge—interior gradient and habitat variables, with abundant edge and interior specialist species. The interior specialist species were positively correlated with distance gradient, humidity, litter depth, canopy cover and the number of palm trees. In contrast, edge-tolerant species were positively correlated with ground cover, light intensity, shrub cover, and per cent of shrub cover between 0.5 and 2 m high but negatively correlated with distance from the forest edge. Changes in habitat structure at the edge of the isolated lowland rainforest may explain babbler species response to edge—interior gradient. From a conservation perspective, edge-avoider species should receive the most attention. Pemahaman tentang gerak balas komuniti burung terutamanya daripada famili Timaliidae terhadap kecerunan pinggir dan kawasan dalaman hutan tropika adalah terhad. Dalam kajian ini, kaedah pensampelan kiraan pada pusat digunakan untuk menentukan komposisi komuniti, limpahan dan kepadatan burung rimba di sepanjang kecerunan pinggir dan kawasan dalaman Hutan Simpan Ayer Hitam, Semenanjung Malaysia. Pemboleh ubah persekitaran diukur di sekitar 25 m dari setiap pusat. Kekayaan spesies burung rimba dan kepelbagaiannya berkolerasi secara positif dengan kelembapan persekitaran, jarak dari pinggir hutan dan bilangan pokok palma. Terdapat hubungan yang jelas antara komposisi spesies burung rimba di sepanjang kecerunan pinggir dan kawasan dalaman hutan dengan pemboleh ubah habitat—terdapat banyak spesies pengkhusus pinggir hutan dan pengkhusus pedalaman. Spesies pengkhusus pedalaman berkolerasi secara positif dengan cerun jarak, kelembapan, kedalaman sarap, litupan kanopi dan bilangan pokok palma. Sebaliknya, spesies pinggir hutan berkolerasi secara positif dengan litupan tanah, keamatan cahaya, litupan pokok renek dan peratusan litupan pokok renek berketinggian antara 0