The impact of anthropic activity based on dam construction and land-use-type in plankton on taxonomic and functional groups

Abstract

Plankton is a vital component of the river ecosystems. The hydrological parameters of rivers alter as cascades develop, resulting in a new pattern within the plankton community. We sampled 27 sections of the Wujiang River's main stream over four seasons from 2022 to 2023 and analysis of plankton and environmental factors. The samples were microscopically examined and classified according to taxonomy and functional groups. To investigate the impact of environmental variables on the plankton community, the study analyzed plankton diversity (α and β), redundancy analysis, the Mantel test, hierarchical segmentation analysis, and a benchmark random forest model. The results demonstrated that the plankton community structure exhibited a combination of river-type and lake-type characteristics in the main stream of the Wujiang River. River cascade dam development caused variance in plankton across and within reservoir areas, with lower reaches exhibiting increased plankton diversity. Elevation emerged as the primary factor influencing plankton diversity and richness, while dissolved oxygen is the main limiting factor for zooplankton and temperature impact succession of phytoplankton. Besides, the land-use-type data was used to discover the influence of cropland and impervious land on plankton. Overall, our study offers valuable insights into the significant effects of different human activities such as cropland, cascade dam and impervious land on the patterns of plankton. It helps to improve our understanding of the intricate relationship between human activities and the plankton community, also provides new ideas and directions for the ecological environment management of the Wujiang River.