Quantitative Assessment of a Mangrove Community in Brgy. Imelda, San Juan, Batangas

Abstract

Mangroves, despite their being one of the most ecologically and economically significant ecosystems, are highly degraded and destroyed due to conversion to fish ponds, salt beds, rice fields, urbanization, housing estates and settlement. While the country has a vast span of mangrove forest, it lacks inventory and assessment. This study aims to provide baseline information on the status of a mangrove community in Brgy. Imelda, San Juan, Batangas. Data on climatic, edaphic and physico-chemical characteristics of water were obtained. The Point Center Quarter Method (PCQM) was used to analyze the mangrove vegetation. Species diversity and richness were determined using Shannon-Weiner, Simpson’s, Margalef’s and Mechenick’s indices. Productivity of the mangrove community was determined using the Nett Canopy Photosynthesis. Results showed that the climatic, edaphic and physico-chemical conditions of the water of the study site were ideal for mangrove growth and development. Vegetation analysis showed that four (4) species of mangroves were found to be thriving in the study site, namely, Rhizophora mucronata Lam., Rhizophora apiculata Blume, Sonneratia alba Smith, and Avicennia marina (Forsk.) Vierh. The Rhizophora species were the most dense, dominant, frequent and important species. These could be attributed to the high preference of Rhizophora species to the prevailing edaphic factors and its morphological adaptations that enable them to survive fluctuating high and low tides and wave actions. Species diversity as well as species richness in the study site were low. The mangrove forest had a high productivity with a value of 6732.4945 g C m’2 year’1. Overall, the study site can be characterized as a developing mangrove community undergoing early stages of secondary succession with evidences of human disturbances.