Predicting the biodiversity hotspots of macrozoobenthos in the Yangtze river basin

Abstract

Identifying the biodiversity hotspots could enrich our understanding for biodiversity conservation. The Yangtze River Basin (YRB) is seriously threatened by multiple stressors leading to rapid biodiversity declines, thus urgently requires an integrated biodiversity conservation. Based on field samplings and the literatures, we described the macrozoobenthos compositions in different reaches and water bodies. We then predicted suitable habitat areas for the main groups, and linked those distributions with key environmental variables. Finally, we analyzed biodiversity hotspots (BHs) of macrozoobenthos and compared them with BHs of large aquatic animals (including fishes, Waterfowls, Yangtze finless porpoise, etc.), and discussed the applicability of selecting macrozoobenthos as biodiversity surrogate for biodiversity conservation. A total of 1033 taxa were recorded. From the upper to lower of YRB, genera number of Oligochaeta and Mollusca increased, of EPT (Ephemeroptera, Plecoptera, Trichoptera) decreased, and of Chironomidae barely changed. In different water bodies, genera number of Oligochaeta, Mollusca, Chironomidae are the highest in lakes of the mid-lower YRB, while that of EPT are the highest in tributaries. Key environmental variables were water body types, elevation and max temperature of the warmest month. The total BHs areas of macrozoobenthos and large aquatic animals in the upper, and mid­lower YRB were 3.54 × 105 km2 and 2.95 × 105 km2, 2.95 × 105 km2 and 1.70 × 105 km2, respectively. The overlapping BHs were 2.0 × 105 km2 and 1.1 × 105 km2, respectively. The BHs of macrozoobenthos had a wider range, and included most BHs of large aquatic animals. Meanwhile, BHs of macrozoobenthos could indicate some habitats those were difficult to cover by selecting large aquatic animals as conservation targets, e.g., seasonal streams and water bodies that suffered from human disturbances. Based on these results, we argue that macrozoobenthos is a good biodiversity surrogate for biodiversity conservation.