Integrating specimen and citizen science data with global records reveals climatic niche expansion and shifts of naturalized plants in China

Research conducted: This study examines the climatic niche dynamics of naturalized plants in China, emphasizing how incomplete species distribution data from digitised herbarium specimens and associated observation records accessible through global data portals (e.g., the Global Biodiversity Information Facility, GBIF) influences the estimation of niche sizes and shifts during species migration and naturalization.Methods: We compared the climatic niche sizes and shifts of naturalized plants using two datasets: one based solely on GBIF and the other integrating digitally available records retrieved from local Chinese sources. We also analyzed niche mismatches to predict ecological niche changes and assess their relationship with climatic adaptability.Key results: The integration of locally mobilised digital datasets significantly improved niche size estimates and revealed more pronounced niche shifts than those inferred from GBIF-only data. These shifts were mainly driven by temperature and seasonality gradients. Reliance on GBIF-only data underestimated the climatic space occupied by naturalized plants, particularly in southern China.Conclusion: Our findings highlight the need for global data providers to integrate, whenever possible, local biodiversity records for a better understanding of the climatic resilience and expansion potential of naturalized species. Such integration is crucial for predicting future distributions and ecological impacts in new environments.