Distribution patterns of macroinvertebrate communities in a Chinese floodgate-regulated river and their relationships with river longitudinal connectivity.

In this study, the Li River and the middle-lower reaches of the Shaying River in the Shaying River basin were selected for an investigation on the effects of floodgates on macroinvertebrate communities; additionally, the relationships among floodgates, macroinvertebrate communities and river longitudinal connectivity were explored. The Li and Shaying rivers had similar ratios of molluscs and scrapers, but their species compositions were significantly different. The water level fluctuations in the Li River were based on natural hydrological characteristics, and these were very different from the fluctuations in the reaches of the Shaying River that were divided by a serious of floodgates.