Effects of anthropogenic disturbance on the species assemblages of birds in the back mangrove forests

Abstract

Around the world, mangrove ecosystem has faced major threats from human activities, and birds were unexceptionally impacted. Mangrove fringe a large extent of the east and west coast of Peninsular Malaysia. The intertidal gradients along the coastline, has formed a brackish zone (back-mangrove), which exhibited different pattern of mangrove species, but received much less attention. In this study, we compare species assemblages of birds based on different level of anthropogenic pressures at different back-mangroves sites; KY; KD and KST which is measured by analysis of land use change for 15 years using ERDAS Imagine. 97 species from 36 families of birds were recorded from all sites, dominated by family Alcedinidae (kingfishers), Ardeidae (egrets, herons) and Coraciidae (dollarbirds). Anthropogenic disturbance changes the landscape structure, with reduction of mangrove cover, other than increasing horticulture, urbanization, and monoculture plantation activities. This is most apparent at KY, followed by KD and lowest at KST, which also showed reducing in species abundance and richness of birds. Species assemblages of birds also differ, as highly disturbed sites exhibited a poorer representation of mangroves-specialist, compared to less disturbed sites as illustrated by the nMDS ordination. Finally, PERMANOVA analysis showed significant effect of the bird family and their ecological niches towards the species assemblages at different back-mangrove sites. The high abundance of open country species such as mynas, crows and doves at all sites indicate the influence of anthropogenic activities. Presence of several highly protected species indicates high conservation value of the back-mangrove zone, apart from their true-mangrove counterparts.