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

Summary This study examines the climatic niche dynamics of naturalized plants in China, emphasizing how incomplete species distribution data from digitized herbarium specimens and associated observation records accessible through global data portals (e.g. the Global Biodiversity Information Facility, GBIF) influence the estimation of niche sizes and shifts during species migration and naturalization. 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. The integration of locally mobilized digital datasets significantly improved niche size estimates and revealed more pronounced niche shifts than inferred from GBIF data alone. These shifts were mainly driven by temperature and seasonality gradients. The use of GBIF‐only data underestimated the climatic space occupied by naturalized plants, particularly in southern China. Our findings highlight the need for global data providers to integrate, whenever possible, local biodiversity records to better understand the climatic resilience and expansion potential of naturalized species. Such integration is crucial for accurately predicting their future distributions and ecological impacts in new environments.