Distribution, diversity and spatial analysis of tree species in a long-term ecological research plot in molawin-dampalit watershed, Mount Makiling forest reserve.
A two-hectare long-term ecological plot (LTERP) was established to generate data for biodiversity resource assessment, monitoring, and evaluation of Molawin-Dampalit watershed for adaptive management. The plot was subdivided into fifty 20 mx20 m subplots where identification of species, measurement of diameter at breast height (DBH) and total tree height and determination of geographic location of all trees were conducted. Growth parameters such as DBH and height were used to monitor and evaluate the area. The study recorded a total of 1,266 tree individuals comprising with 135 species distributed among 95 genera and 58 families. Of the 135 species recorded, 87 species are native or indigenous and 4 species are exotic or introduced in the area and 44 species are found to be endemic to the Philippines showing a 32% endemism profile for the whole study area. Three most dominant species include Diplodiscus paniculatus Turcz, Celtis luzonica Warb, and Pinanga insignis Becc based on Species Importance Value. A total of 29 threatened species were recorded in the area. The study revealed dominance of threatened species in the LTERP area. Out of 10 dominant species, 7 are threatened species and 3 of which are critically endangered species such as Parashorea malaanonan (Blanco) Merr and Diospyros blancoi A. DC. Tree diversity analysis showed a high species richness (135), evenness (0.71), Simpson diversity index (0.91) and Shannon Diversity Index (3.52) indicating a more diverse area, preserved and intact MMFR. Spatial analysis was correlated with the clustering of species using ordination method. Results showed species composition is affected by spatial distribution and each subplot may have different site requirements and unique floral characteristics.