ASSESSMENT ECOLOGICAL HEALTH OF THE BA LAI RIVER BY THE MATURITY INDEX OF THE FREE-LIVING NEMATODE COMMUNITIES

Abstract

Nematode communities were sampled in 2 seasons: the rainy season in 2019 and the dry season 2020. The analysis results of the colonizer- persister index (c-p) showed that the Ba Lai river nematode community was mainly equal to 2, this is the group of nematode, living in disturbed environmental conditions. In and outside the dam in the two seasons, low c-p nematode appeared, showing signs of pollution in the bottom of the Ba Lai river, not improved from the rainy season to the dry season. The Maturity index (MI) in the two seasons at the dam base sites (G3, G4) were all low, giving poor quality basal loss. Besides, the point G16 in the dam has low MI in the dry season while MI in the high rainy season, proving that upstream is saline intrusion. Timely measures should be taken to minimize pollution and saline intrusion in the Ba Lai River, as well as to limit the impact of dams on the bottom ecosystem.