Zooplankton in a continuous waterscape: environmental and spatial factors shaping spring zooplankton community structure in a large canyon reservoir at the tropic of cancer

Abstract

Reservoirs are continuous waterscapes that exhibit hydrodynamic characteristics of both lakes and rivers with water flow. These dynamic habitats provide a novel chance to explore the effects of metacommunity dynamics on community structure in relation to environmental, spatial, and temporal processes. We investigated the spatial distribution of spring zooplankton communities in a large reservoir in southern China. We intensively sampled along a longitudinal gradient during early and full spring. We compared the relationship of environmental and spatial variables to the community structure of three zooplankton groups: rotifers, cladocerans, and copepods. The overall composition and abundance of zooplankton groups across longitudinal zones became more heterogeneous with increasing environmental heterogeneity across sampling periods. Multi-level ANOVA and PERMANOVA results showed that rather than homogenize the environment, water flow in late spring increased spatial heterogeneity in the environment and increased the importance of species sorting in shaping the zooplankton community. However, variation partitioning analysis showed that the influence of environmental and spatial variables also varied across the three zooplankton groups likely due to their differences in both physiological and morphological adaptation. Our study shows that metacommunity processes are important in structuring zooplankton communities in reservoir waterscapes that are influenced by flow.