Toward 30×30: Mapping in-situ Climate Refugia for Biodiversity Conservation across Mainland China

Context Climate change poses significant threats to biodiversity by altering habitat conditions, thereby challenging the effectiveness of protected area (PA) networks. In-situ climate refugia—areas with stable climatic conditions—are increasingly recognized as essential for sustaining species persistence under future climate scenarios. Objectives This study aims to identify potential in-situ climate refugia across mainland China for 311 endangered terrestrial vertebrates under two future climate scenarios (SSP2-4.5 and SSP5-8.5). We further evaluate the spatial congruence between these refugia and China’s existing PA network to inform strategic conservation planning toward achieving the “30×30” target. Methods A climatic niche-based framework was developed to identify potential in-situ climate refugia by integrating species-specific climatic tolerance, climate change intensity, habitat suitability, and habitat quality. Climate change intensity was quantified using standardized Euclidean distance, and species-specific niche widths were used to define thresholds for climatic stability. Potential climate refugia were delineated by overlaying climate stability with habitat suitability and quality, and subsequently compared with existing PAs to identify conservation gaps. Results Our results reveal that 23.66% of China’s land area could function as climate refugia, but only 15.25% of these regions are currently protected. High-potential refugia, mainly located in the subtropical evergreen broadleaf and tropical monsoon forest zones, are severely underrepresented (8% coverage). Incorporating these refugia into PA networks could raise coverage from 18–25%, offering a realistic pathway to meet the 30×30 target of conservation. Conclusions The proposed framework offers a scalable approach for climate-informed conservation planning. To ensure biodiversity resilience, China should prioritize integrating high-potential refugia into national and regional PA strategies. This approach can significantly enhance ecological representativeness and climate adaptation capacity in PA networks.