Abundance, Structure, and Diversity of Mangroves in a Community-Managed Forest in Calatagan, Batangas, Verde Island Passage, Philippines

The number of mangroves in the world has been alarming that poses a big threat to destruction of the marine ecosystem. Some of these threats include habitat destruction, invasive species, over population, over exploitation, and pollution. This research aimed to determine the species abundance and diversity of a community-managed mangrove forest in Calatagan Marine Protected Area through its community structure. A survey of the vegetation structure of mangrove was conducted to determine the GBH (girth at breast height), height and the tree’s crown in the four (4) standard 10 m x 10 m transect plots. DBH (diameter at breast height), basal area, canopy cover, relative frequency, relative dominance and relative density were also assessed. Species diversity and abundance were computed using the Shannon-Weiner diversity index. The results of the community structure in average revealed that the GBH is 13.57 cm, height of 3.50 m, crown 1.28 m, DBH of 4.32 cm, basal area of 0.0164 m2 and canopy cover of 5.30 m2. The study shows a very low species diversity value (H’) ranging from 0.4692 to 1.2178. Seven species belonging to six families of mangroves were identified. Avicennia marina was determined to be the most dominant among the identified species in the sampling plots. With these results, conservation of mangrove forest by the local community stakeholders can be strengthened to improve the community structure towards the resiliency of the mangrove forest. It is endorsed that community-based conservation of mangroves can be considered in mangrove management, monitoring and evaluation.

Keywords – abundance, community-managed forest, conservation, diversity of mangroves, structure,