Data and code from: River network connectivity reductions dominate declines in the richness of plateau fish species under climate change in the upper Yangtze River Basin

Anthropogenic climate change and disrupted river network connectivity are
major factors affecting freshwater fish richness. However, the
distribution patterns of this parameter under the combined influence of
climate change and reduced river connectivity resulting from hydroelectric
development remain unclear. Here, we projected shifts in the richness of
Schizothoracinae fish species, the most dominant and economically
significant type of fish on and around the Qinghai‒Tibet Plateau. Stacked
species distribution modeling and predictions were explored to simulate
the range shifts of twenty species in the upper Yangtze River Basin under
the impacts of connectivity and climate changes. The results revealed that
river connectivity reduction dominated the richness shifts and loss in
Schizothoracinae fish species. Higher-quality fish habitats are more
susceptible to the impacts of connectivity reduction. Although the
connectivity reduction caused by dam construction is associated with a
slight increase in fish richness in the source region of the basin, it is
primarily responsible for the widespread decrease in fish richness under
future climate change scenarios. In the 2050s and 2090s under the two
shared economic pathway scenarios, future climate change is predicted to
enhance the positive impacts of river connectivity changes on fish habitat
in the middle to high latitude regions of upper basins but worsen their
negative impacts in other regions. Our study highlights the dominant role
of river connectivity in influencing freshwater fish richness in the
context of climate change, thereby highlighting the importance of
connectivity restoration in global freshwater biodiversity conservation
and water resource management.