Tree species diversity of the reparian vegetation along Sibalom River, Leon, Iloilo

Abstract

Riparian vegetation is perhaps one of the least recognized and appreciated ecosystems in the country, despite its crucial role in delivering ecosystem services. Unfortunately, there have been few studies conducted in the country, particularly in Sibalom River, Leon, Iloilo. Baseline information is necessary to assess the current status of this vegetation. Thus, this study aimed to determine the tree species diversity of the riparian vegetation along Sibalom River. Specifically, it sought to calculate tree density, relative density, the Shannon-Weiner Index of Diversity (H'), and Simpson’s Evenness Index (J'), Six plots were delineated and surveyed: two upstream, two midstream, and two downstream. Results revealed a total of 467 individual tree species and 34 tree species documented, representing 16 families. Swietenia Mahogani, an invasive species, was found in all plots and exhibited the highest density, with some undergoing naturalization. Twenty native species and 14 introduced species were identified. Twenty-four species were classified as least concerned, while two were vulnerable and one endangered. Overall diversity was moderate at H' = 2.72, while the Evenness index, J' = 0.07, indicated very low distribution of individuals among species. Geographical Information System analysis showed that species diversity is affected by factors such as human activities, especially construction, water movement, and land use.