Determinants of community structure of zooplankton in heavily polluted river ecosystems.

Wei Xiong,Yiyong Chen,Baoqing Shan,Weimin Wang,Aibin Zhan,Jie Li

doi:10.1038/srep22043

Abstract

River ecosystems are among the most affected habitats globally by human activities, such as the release of chemical pollutants. However, it remains largely unknown how and to what extent many communities such as zooplankton are affected by these environmental stressors in river ecosystems. Here, we aim to determine major factors responsible for shaping community structure of zooplankton in heavily polluted river ecosystems. Specially, we use rotifers in the Haihe River Basin (HRB) in North China as a case study to test the hypothesis that species sorting (i.e. species are “filtered” by environmental factors and occur at environmental suitable sites) plays a key role in determining community structure at the basin level. Based on an analysis of 94 sites across the plain region of HRB, we found evidence that both local and regional factors could affect rotifer community structure. Interestingly, further analyses indicated that local factors played a more important role in determining community structure. Thus, our results support the species sorting hypothesis in highly polluted rivers, suggesting that local environmental constraints, such as environmental pollution caused by human activities, can be stronger than dispersal limitation caused by regional factors to shape local community structure of zooplankton at the basin level.

Highlights

River ecosystems are among the most affected habitats globally by human activities, such as the release of chemical pollutants
Some studies showed that the dispersal capacity of organisms determined local community structure[13,14], while others illustrated that local environmental factors, such as water temperature, pH, salinity, trophic state or combinations of these factors were responsible for shaping local community structure[15,16]
Based on the conceptual framework constructed by Heino et al.[18], environmental factors are likely to be most important for shaping community structure when dispersal rates are intermediate[19]

Summary

Introduction

River ecosystems are among the most affected habitats globally by human activities, such as the release of chemical pollutants. We use rotifers in the Haihe River Basin (HRB) in North China as a case study to test the hypothesis that species sorting (i.e. species are “filtered” by environmental factors and occur at environmental suitable sites) plays a key role in determining community structure at the basin level. Our results support the species sorting hypothesis in highly polluted rivers, suggesting that local environmental constraints, such as environmental pollution caused by human activities, can be stronger than dispersal limitation caused by regional factors to shape local community structure of zooplankton at the basin level. It remains largely unknown how and to what degree environmental changes derived from chemical pollution influence community structure and geographical distribution of biodiversity, zooplankton, in river ecosystems. We use rotifer communities in the most polluted river in China, the Haihe River Basin, to test the species sorting hypothesis at the basin scale

Objectives

Methods

Results

Conclusion