Woody Species Diversity and Conservation Status of Tumauni Watershed Natural Park, Isabela, Philippines

The study was conducted within the Protected Area of the Tumauini Watershed Natural Park located in the municipality of Tumauini province of Isabela along the western part of the Northern Sierra Madre Natural Park. The protected areas in the Philippines cover 39% of the total forest cover. Protection and conservation of protected areas is significant due to the increasing habitat loss and biodiversity loss. The main objective of the study is to assess the tree diversity of the park using the modified belt-transect method adopted by the Department of Environment and Natural Resources (DENR). The transect line has a distance of 2 kilometers and a total of 9 stations. A Nested Quadrat was established along the transect line for tree identification. Results of the assessment show that the park has a species richness of 34 tree species in eight families and 26 genera. Species diversity indicates low (2.4) to very low (1.12) based on the Shannon-Weiner Diversity Index despite the high number of individuals found in the watershed area. The low diversity of the watershed is affected by the rampant anthropogenic activities and naturally-induced hazards occurring in the protected area. Shorea polysmerma is the most dominant and the most important species, with an Importance Value index of 38.78. Three species of trees were recorded as generalists in the area such as Calophyllum blancoi, Shorea palosapis, and Ficus sp.