Patterns and drivers of potential range shifts of Symplocos species in China under climate change

Climate change and human activities profoundly impact forest biodiversity, with effects projected to intensify. The Symplocos genus, a diverse assemblage of flowering plants prevalent in the subtropical and tropical forests of the Yangtze River in China, holds substantial economic and medicinal value. However, the impacts of climate change and human activities on the habitat ranges of Symplocos species in China remain unclear. Here, we employed an optimized Maxent model to predict potential habitats for four key Symplocos species under current and future climatic scenarios (SSP1-2.6 and SSP5-8.5) and examined factors that could affect species’ range shifts, including climatic, topographic, pedologic and anthropogenic variables. Our results indicate that the habitat ranges of the four Symplocos species are mainly concentrated in central south, east, and southwest China under the current climate scenario. Furthermore, the habitat ranges of S. setchuensis, S. chinensis, S. groffii, and S. sumuntia were primarily influenced by the mean temperature of the driest quarter, the minimum temperature of the coldest month, the temperature annual range, and precipitation seasonality, respectively. Notably, human activities have a positive impact on the habitat ranges of these species. Under future climate scenarios, S. groffii and S. sumuntia are projected to expand their ranges significantly northward, while S. chinensis is expected to maintain stable habitat, and S. setchuensis may face considerable contractions. These findings offer critical insights for the targeted conservation of Symplocos diversity and germplasm resources, highlighting the importance of prioritizing regions vulnerable to habitat loss from climate change.