Author:

Abstract

Being a tropical country located close to the equator, Sri Lanka is blessed with diverse mangrove ecosystems. However, most of its mangroves have not been studied in detail particularly in the northern areas. Although the Bentota river is located in one of the highly populated districts, mangroves along its banks have not been studied in detail for species composition and diversity. Hence, the present study focused on determining the diversity and abundance of true mangrove species associated with the Bentota river. Mangrove vegetation was sampled using 5 m wide belt transects laid perpendicular to the shoreline. True mangrove species in each transect were identified and gbh (Girth at Breast Height) and height were measured in all individuals. Shannon diversity (H’), Shannon Evenness (E), and Sampson index (D) were used to calculate and compare the diversity between sites. A total of ten true mangroves and 13 associates were recorded for the first time from the Bentota River. Nine (9) true mangrove species from the estuary area and eight from Kaluwamodara tributary were recorded whereas the least number of species (5) were recorded from the Meegama tributary. The highest Shannon diversity value (H’ =1.83) was recorded in the Kaluwamodara tributary followed by the estuary area (H’ =1.47). Approximately half of the true mangrove species (10) that have been recorded from Sri Lanka occur in the Bentota river mangrove. As some threatened mangrove species and numerous anthropogenic threats were recorded during the present study, immediate actions should be taken by the government to conserve mangroves in Bentota river.

Keywords: Bentota river, Floristic Composition, Diversity, River mangrove

How to Cite: Gunawardana, B. H. S. M. (2022). Floristic composition of mangroves in Bentota River, Southwestern Sri Lanka. Ceylon Journal of Science, 51(4), 395–405. DOI: http://doi.org/10.4038/cjs.v51i4.8057