Species Diversity of Beetles (Coleoptera) Along an Elevational Gradient in Mount Busa, Lake Sebu, South Cotabato, Philippines

A field survey of beetles (Coleoptera) was conducted in a key biodiversity area in Mt. Busa, Lake Sebu, South Cotabato. The area is known for its rich flora and fauna; however, the area is still poorly studied, especially the Coleoptera. Thus, this study provided the preliminary data on the diversity and abundance of beetles in the area. Different sampling methods were performed including transect walk, and combination of random and opportunistic sampling techniques. The sampling was done in four forest types with elevations from 900-1,700 meters above sea level (masl) including the open habitat (900-1,000 masl), lower montane's open forest (1,100-1,300 masl) and closed forest (1,400-1,500 masl), and upper montane ( 1 ,600-1,700 masl) Additionally, physicochemical parameters such as temperature and humidity were recorded. A total of 559 individuals belonging to 13 families, 33 genera, and 51 species were recorded. Notably, I new species and 2 potential new species were recorded. Among the 4 sites, the lower montane's open forest (H' = 3.25; 1 - D = 0.95) and closed forest (H' = 2.92; 1 - D = 0.93) exhibited the highest species abundance and diversity. The results of the study show that the species distribution was slightly even in all sites. Effective Number of Species (ENS) indicates that 12 species from open habitat, 25 species from open forest, 18 species from closed forest, and 7 species from upper montane were equally abundant. Canonical Correspondence Analysis (CCA) revealed that the diversity of Coleoptera fauna is significantly influenced by temperature and humidity, suggesting that Coleoptera fauna are vulnerable to the future effects of climate change and anthropogenic activity. Thus, it is recommended that more field surveys must be conducted. Conservation laws and policies must be strongly implemented, and lower montane must be officially declared as a biodiversity hotspot in Southern Mindanao.