Macrobenthic invertebrate structure, diversity, and water quality indicators in Jhelum tributaries of Kashmir Himalaya.

Macrobenthic invertebrate communities are groups of large, bottom-dwelling organisms without backbone that inhabit aquatic environments such as streams, rivers, ponds, wetlands, lakes, and oceans. These communities represent diverse invertebrate groups which include aquatic worms, leeches, clams, snails, amphipods, crabs, aquatic mites, and insect larvae. Macrobenthic invertebrates are regarded as primary functional feeding groups in the fluvial ecosystems and an outstanding tool for monitoring the water quality. Our study aimed to investigate the community structure and diversity of macrobenthic invertebrates along with the water quality of Jhelum tributaries from Kashmir Himalaya. In the entire study, a total of 49,681 individuals of macrobenthic invertebrates were collected, belonging to 3 phyla and 51 families. The maximum abundance and richness were observed in Arthropoda followed by Mollusca and Annelida. The overall range of the Shannon-Wiener index ranged from 1.79 to 3.70 in the Aripal stream and 1.60‒3.74 in the Watalara stream, which indicates a moderate clear water quality in the streams. The maximum abundance, richness, and diversity were reported in the midstream region of both tributaries and during summer and autumn seasons. The overall dataset suggests that temperature and nutrients have a major influence on the diversity, richness, and abundance of the streams. Canonical correspondence analysis revealed that the taxa show a positive correlation with temperature and nutrients indicative of tolerant and semi-tolerant families respectively whereas the taxa showing a negative correlation with nutrients and ions reflect sensitive families. The dendrogram confirmed the spatial distribution of macrobenthic invertebrate families into three categories wherein cluster-I, cluster-II, and cluster-III represent the presence of sensitive, semi-tolerant, and tolerant families, respectively. Based on the values of biotic scores, sites A1, W1, A2, and W2 lie under class I water quality with high ecological status and none to very slight organic pollution while sites A3 and W3 lie under class II water quality with good ecological status and presence of moderate pollution. The structure and assemblage pattern of macrobenthic invertebrates along with the water quality status provide information about the ecological stability of the stream ecosystem. These aspects also give important clues to the functional status of the Himalayan stream ecosystem depicting an apparent gradient in the stream substratum, habitat, and water quality. The prevalence of aquatic insects reflects the diversity in the form and habitat, presence of functional feeding groups, strong dispersal capability, and colonization of microhabitats in the streams. The overall study focuses on the ecological importance of macrobenthic invertebrates along with the health status of fluvial ecosystem.