Trace Elements and Temperature Combined to Regulate Zooplankton Community Structures in Mountain Streams.

Zooplankton, as an important component of mountain river ecosystems, play a crucial role in the cycling of matter and the flow of energy. However, the depth and systematic research on the formation mechanisms and influencing factors of zooplankton communities in mountain streams are poorly understood. Here, we conducted field sampling and investigated the spatiotemporal distribution of the zooplankton community structure and the major environmental factors in mountain streams to explore the principles underlying their effects on the zooplankton community. The results showed that zooplankton community structure exhibited significant seasonal variations. Rotifera and Cladocera were the dominant groups, with Rotifera dominant in warm weather and Cladocera dominant in February. The analysis revealed that temperature and trace elements are the main factors affecting zooplankton diversity. Our model explained 46.50% of the variation in zooplankton through temperature, water properties, nutrients, and trace elements. The results highlighted that temperature acted directly on the zooplankton community and also exhibited indirect and negative effects on zooplankton diversities through altering trace elements. Trace element variables had a significant impact on zooplankton community distribution. Our study systematically quantified these relationships, providing insights into the ecological processes of mountain streams and offering a scientific basis for the ecological protection of mountain streams.