Floating photovoltaic systems homogenize the waterbird communities across subsidence wetlands in the North China Plain.

Photovoltaic (PV) power generation provides an environmental-friendly alternative to fossil fuels, but the potential impacts of large-scale PV systems on wildlife have become a hotspot. In the North China Plain, floating photovoltaic (FPV) systems have been extensively installed across subsidence wetlands created by underground coal mining. However, there have been no studies investigating the effects of FPV systems on waterbird communities. During the wintering and migrating seasons of 2016-2017 and 2021-2022, we carried out waterbird surveys in subsidence wetlands with and without FPV systems in the Huainan-Huaibei coal mining area in the North China Plain to examine the effects of FPV systems on waterbird communities. After installation of FPV systems, waterbird numbers increased, but Simpson diversity and Pielou evenness decreased, with no significant changes in species richness. The presence of FPV systems resulted in decrease in the proportion of diving birds but increase in the proportion of vegetation gleaners. The FPV systems leaded to decrease in the proportion of herons in October but increase in other months. Besides the effect of FPV systems, we also found that Simpson diversity and the proportion of ducks increased, while the occurrence rate of shorebirds and gulls decreased from 2016 to 2021. Our results indicate that the cover of FPV systems may homogenize waterbird communities across subsidence wetlands. This study provides the first information on the effects of the FPV systems on waterbirds in artificial wetlands and highlights the need for further research to understand the ecological implications of FPV installations in wetland ecosystems.