Distribution of major floral and faunal diversity in the mountain and upper gangetic plains zone of the Ganga: Diatoms, macroinvertebrates and fish

Abstract

Present study examines the distribution of biodiversity elements (diatom, macroinvertebrate and fish) in respect of their taxonomic richness, density, composition in the high gradient mountain zone (MZ) and low gradient plains zone (PZ) consisting PZ I (Hardwar to Allahabad) and PZ II (Allahabad to Varanasi). The richness of benthic diatom and algal flora declines with loss of substrate heterogeneity from MZ to PZ, but that of plankton, macroinvertebrate and fish, increases gradually. Diatom predominate the benthic flora in MZ but richness declines mildly in PZ. The plankton community of PZ is mildly richer in diatom flora, as share of green algae is substantial. The macroinvertebrate fauna is predominated by insects in the MZ and a combination of insects and molluscs in the PZ. Low Jaccard's similarity and high distances among MZ and PZ I, illustrate unique flora in these zones. Since, PZ II shows greater distance from both MZ and PZ I, this zone has different biodiversity in respect of these communities. In contrast the fauna is unique in MZ, while PZ I and PZ II have relatively more similarity, less in case of macroinvertebrate but high in fish.