Diversity of benthic macroinvertebrates in Quiaoit and Baroro River Watersheds, Ilocos Region, Philippines

Josephine Garcia; Aurelio Delos Reyes; Laura David; Aileen Simondac-Peria

Josephine Encisa-Garcia Department of Social Forestry and Forest Governance, College of Forestry and Natural Resources, University of the Philippines Los Baños, College, Laguna, Philippines
Aurelio A. Delos Reyes Land and Water Resources Division, Institute of Agricultural Engineering, College of Engineering and Agro-Industrial Technology, University of the Philippines Los Baños, College, Laguna, Philippines
Laura T. David Marine Science Institute, University of the Philippines Diliman, Quezon City, Philippines
Aileen C. Simondac-Peria Office of the Coordinator for Research, Extension and Linkages (OCREL), College of Forestry and Natural Resources, University of the Philippines Los Baños, College, Laguna, Philippines

Keywords: diagnostic taxa, forest, land cover, pollution-tolerant organism, water quality

Abstract

Benthic macroinvertebrates are small, aquatic, and bottom-dwelling animals found in lakes, rivers, and streams. Its sensitivity to environmental changes makes them important for assessing an aquatic ecosystem's water quality and health. This study mainly explored the benthic macroinvertebrates communities of two important watersheds in the Ilocos Region. Thirty-seven families were collected from 54 samples in eight sites in two different seasons. Family Thiaridae, specifically Melanoides species, was dominant in both watersheds during the dry season, 79% in Baroro River Watershed and 42% in Quiaoit River Watershed. Melanoides and Martesia species were present during the wet season, with 44% in Baroro River Watershed and 17% in Quiaoit River Watershed. The presence of diagnostic taxa in both study areas and during both seasons was also observed. Limnodrilus hofmeisteri and Chironomous species were collected along the Quiaoit River Watershed, specifically in the sampling station near the forested area or the middle stream. These two aquatic organisms are classified as pollution-tolerant organisms that can survive in areas with poor water quality. The result revealed fewer macroinvertebrates fauna collected in sampling sites near the forest. Conversely, the diversity of macroinvertebrates was higher in stations near settlement and estuary. These findings showed the sensitivity of macroinvertebrates at different levels, which could be attributable to anthropogenic activities.