Water Quality and Anthropogenic Impact Assessment Using Macroinvertebrates as Bioindicators in a Stream Ecosystem

Dachigam-Dara catchment feeding the world-famous Dal Lake was assessed and evaluated for water quality and anthropogenic impacts using physico-chemical and biological data from 2016 to 2018. Seven sites belonging to Dachigam (DACZ) and Dara zone (DARZ) catchment, three sites from the confluence zone (WANZ), and two sites at the downstream end (TELZ) were selected characterized by varying degrees of anthropogenic pressures. Biological Monitoring Working Program, and Average Score Per Taxon at the upstream zones (DACZ, DARZ, and WANZ) recorded significantly higher scores with water quality indices falling within the good category than the downstream zone (TELZ). Taxa richness, and diversity indices of benthic macroinvertebrates recorded higher values at the upstream zones (DACZ, and DARZ), and confluence zone (WANZ), compared to the downstream zone (TELZ). Results revealed that phylum Arthropoda was most dominant contributing 37 invertebrate families (constituting 90% of the total macroinvertebrate community, including Crustacea and Arachnida) while phylum Mollusca and Annelida constitute 5% each. Macroinvertebrate families Baetidae, Erpobdellidae, Gammaridae, Chironomidae, and Heptagenidae contributed significantly to the similarity and dissimilarity between the sampling zones. The best subset of environmental variables (BIOENV) test revealed that the distribution of benthic macroinvertebrate assemblage in the Dachigam-Dara catchment is driven by pH, electrical conductivity, dissolved oxygen, and phosphate phosphorous. The upstream zones (DACZ, and DARZ) and confluence zone (WANZ), compared to the downstream zone (TELZ) suggest progressive shift of pollution sensitive macroinvertebrate taxa to pollution tolerant taxa in response to anthropogenic activities in the stream ecosystem over time.