Ecological Health Assessment of the Vam Co River System, Vietnam: Insights from Benthic Macroinvertebrates and Environmental Changes

Abstract

This research examines the relationships between benthic macroinvertebrates and environmental variables in the Vam Co River system, located in Southern Vietnam. Field surveys conducted four times between May and November 2023 were designed to assess seasonal changes in macroinvertebrate diversity and water quality. The river system, characterized by low to moderate pollution levels, elevated nutrient concentrations, and substrates dominated by fine sand and coarse particulate matter, plays a significant role in shaping the distribution and abundance of benthic macroinvertebrates. A total of 32 species were recorded, with bivalves and crustaceans being the most dominant groups during monitoring periods. Benthic macroinvertebrate densities fluctuated from 28 to 167 individuals/m², reflecting habitat suitability associated with substrate composition. Biodiversity, measured by the Shannon–Wiener index (H'), ranged from 1.51 to 2.94, while the Average Tolerance Score Per Individual (ATSPI) varied between 37 and 51, suggesting ecological health conditions ranging from moderate to good levels. Species richness showed positive correlations with pH, total suspended solids (TSS), and dissolved oxygen (DO), indicating these variables support diverse communities. In contrast, ATSPI scores reflecting pollution tolerance, were positively correlated with biochemical oxygen demand (BOD₅), total nitrogen (T_N) and total phosphorus (T_P), and negatively correlated with pH, TSS, and DO. These findings highlight the role of benthic macroinvertebrates as key indicators assessing the ecological health of river systems. They also emphasize the importance of implementing long-term, integrated monitoring and adaptive management strategies to ensure the sustainable protection of the Vam Co River system.