Against the backdrop of increasing extreme weather events (EWEs) due to global climate change, and given the limited research on their impact on aquatic ecosystems, this study investigated the effects of floods and blizzards on periphytic algal communities in seven water bodies in the Shennongjia Forestry District, China. We hypothesized that EWEs would reduce periphytic algal diversity, weaken community stability. Results revealed that EWEs significantly decreased periphytic algal biomass (by 92.9% ± 2.9%), richness (1.3% ± 0.2%), evenness (21.5% ± 4.0%), and Shannon diversity (7.0% ± 1.4%) (P 0.05). Additionally, these events destabilized the co-occurrence networks by reducing node connectivity, centrality, and complexity, resulting in structural simplification that diminished the system’s ability to withstand disturbances. Floods specifically increased water velocity (58.1%) and created shading, leading to a decline in algal diversity. In contrast, blizzards drastically reduced water temperature (69.5%), posing severe survival challenges to the algal communities. It was concluded that EWEs reduced community’s diversity by altering habitat heterogeneity and weakened network stability through changing in species’ adaptation and community shifts. Water temperature and velocity were identified as key drivers of community composition changes during EWEs. This research provided insights into the mechanisms of climate change affecting periphytic algal communities.
Zhu et al. (2026) studied this question.