Role of Macroinvertebrates as Bioindicators and Resident's Perception on Water Quality in Bilar River, Bohol, Philippines

This study investigates the diversity and use of macroinvertebrates as bioindicators of water quality in three selected sites of Bilar River. River usage, management issues and people’s perception on water quality were also assessed. Kick and sweep sampling methods were used to collect macroinvertebrate samples and physico-chemical parameters of the river were measured. Ecological parameters using standard indices were employed to describe macroinvertebrate diversity. A total of 12 macroinvertebrate species belonging to seven orders under four classes (Bivalvia, Gastropoda, Malacostraca and Insecta) were encountered. Results revealed that the two most abundant macroinvertebrate groups were found to be tolerant and very tolerant, suggesting that the water quality is considered “degraded to poor” based on tolerance ranking. Results show that Site 2 (Brgy. Poblacion) had the highest diversity, evenness, and richness index values, but lowest in dominance among the sites. Mean water pH was slightly acidic with low water temperature while water depth, flow and velocity were influenced by the presence of man-made dams and land bridges in the sites that hamper natural water flow. Bilar River plays an important role in the local community as irrigation and food sources but poor solid waste management in the area threatens its quality. Respondents believed that the river’s water quality is deteriorating and will continue to deteriorate through the years, thus, conservation measures should be done to protect its health.