Macroinvertebrate communities in streams in the Himalaya, Nepal

摘要: SUMMARY 1 Macroinvertebrates were sampled in the riffles of fifty-eight streams from three regions Himalaya (Anapurna, Langtang and Everest) Nepal. A semi-quantitative method with identification to family level was used describe communities on-site. 2 Stream physicochemistry assessed community structure macroinvertebrates related chemistry, physiography (substratum composition, altitude size), geographical location dominant land use each catchment (terraced agriculture, forest or scrub). Community data analysed by ordination (DECORANA) classification (TWINSPAN). 3 The concentration cations stream water decreased significantly altitude. Chemistry also differed between regions; sites Anapurna had a higher pH conductivity than those other two areas. 4 Communities dominated aquatic insect larvae, Ephemeroptera, particular Baetidae, most numerous across sites. 5 There were, nevertheless, differences sites, which closely physicochemistry. Ordination scores strongly correlated altitude, magnesium substratum composition. Classification linked differentiating high-altitude low silica concentrations others. Sites Everest regions, their contrasting separated. 6 Community use: draining catchments terraced agriculture different scrub forest. This result confounded, however, strong relationship use, chemistry; terracing at lower proportion fine sediments land-use types. 7 Overall, our indicate that natural features relief geology create gradients invertebrate faunas, but activities man may have an effect on ecology through management.