Community Structure and Diversity of Carabid Beetles in Eastern Visayas, Philippines

Abstract

                A pioneer study has been carried out to provide data about community structure and diversity of carabid beetles in six forests of Eastern Visayas namely: Lake Danao, Mt. Nacolod, Kuapnit Balinsasayao, Asug Forest, City Forest, and Closed Canopy on January to June of 2019. Collected carabid beetles was comprised of 7844 individuals belonging to 41 species under 25 genera, 13 tribes, and two (2) subfamilies. Twenty-six species were recorded from Lake Danao, 32 species in Mt. Nacolod, 20 species in Kuapnit Balinsasayao Forest, 11 species in Asug Forest, 19 species in City Forest, and 26 species in Closed Canopy Forest. A total of 19 endemic species were recorded of which 12 are Philippine endemic, 6 are endemic to Leyte, and 1 is endemic to Samar. The survey found new species and new records of carabid beetles in the region.  Carabid beetles were collected using pitfall traps and handpicking (ground searching). Carabid species diversity, as estimated by diversity indices, was significantly different among the six forests.  Of the six forests, Mt. Nacolod had comparatively high diversity (4.00). equitability (0.78), dominance (2.709), and species richness (32); Lake Danao and Closed Canopy forests had almost the same values in high diversity (3.37), equitability (0.86), dominance (2.798), and species richness (26). Indices for Kuapnit and City forests did not differ significantly, both have low diversity (2.787 and 2.464), high equitability (0.85 and 0.89), dominance (2.53 and 2.58), and species richness (20 and 19), but were relatively lower than Mount Nacolod. Asug forest got the lowest indices value for both dominance, diversity and species richness. In terms of habitat types, there were 41 species belonging to 25 genera identified among 3,771 carabids collected from natural forests of Eastern Visayas. In agricultural habitat type, 28 species were identified from 4, 073 carabid beetles. Natural forest had comparatively high diversity (5.95), high equitability (0.80), dominance (3.1), and species richness (41) over agricultural land.