Floristic Diversity, Composition and Richness in Relation to Topography of a Hill Dipterocarp Forest in Malaysia

摘要

A study along the gradient directed transect was conducted in a hill dipterocarp forest at Ulu Muda Forest Reserve, Kedah, Peninsular Malaysia to study tree species composition, distribution, richness and diversity in relation to topography. A total of 2,421 individuals belonging to 421 species, 187 genera and 57 families across all size classes of trees from 1.5-m height and above were enumerated and identified. The species number represents 15% of the total tree species recorded from Peninsular Malaysia of which 47 were endemic and 22 rare species. Seventy four species were new records for the state of Kedah while one species Nephelium hypoleucum was a new record for Peninsular Malaysia. The distribution of species and individuals in families as well as the distribution of species with different sizes of stems followed an inverse J-shaped pattern. Euphorbiaceae and Dipterocarpaceae represented as two most dominant families. Shannon's index of diversity registered a higher diversity index of 5.61 for the study site as a whole than other reported figures elsewhere. Species accumulation curves for different tree size classes showed no tendency to flatten out but continue to rise. A total of nine dominant species showed strong association with topography when subjected to the chi-square test. Multivariate cluster analysis and Principal Component Analysis (PCA) detected the topographic component of floristic variation between different topographic locations.