The impact of forest conversion on bird communities in the northern flank of the Knuckles Mountain Forest Range, Sri Lanka

Initiating proper conservation and management strategies requires assessing the consequences of forest conversion into human land use systems on tropical biodiversity. This study characterized bird species diversity and composition and vegetation structural components in four land use types in the northern flank of the Knuckles Mountain Forest Range, which is a part of a world heritage site in Sri Lanka: an undisturbed forest and three human-modified land uses for cardamom, pinus, and abandoned tea plantations. Using the fixed radius point count method, 1,023 individuals belonging to 51 bird species were recorded. The cardamom plantation with native shade trees had a bird species richness and composition comparable to an undisturbed forest (one-way analysis of variance; p > 0.05, Jaccard index = 0.56). Based on the Shannon–Wiener index, the overall species diversity was highest in the undisturbed forest. Pearson's correlation coefficient suggested a strong positive linear relationship between bird species richness with canopy cover (r = 0.738) and vertical stratification (r = 0.813). Land use systems formed by considerable alterations to vegetation structure significantly reduce bird diversity and supports a bird community that is less comparable to an undisturbed forest.