Potential Suitable Habitats and Spatial Responses of Different Actinidia Species Under Different Climate Scenarios

Climate change may elicit divergent spatial responses among species sharing ecological traits or close taxonomic relationships. Here, we compared six Actinidia species organized into three focal pairs: the cold-tolerant pair (A. arguta–A. kolomikta), the closely related cultivated pair (A. chinensis–A. deliciosa), and the warm-humid pair (A. eriantha–A. latifolia). Species-specific MaxEnt models were used to project potentially suitable habitats in China under SSP126, SSP245, and SSP585 for 2041–2060 and 2081–2100, based on future climate data from the BCC-CSM2-MR model. PCA-env analyses and randomization tests assessed niche overlap and equivalency, while habitat transitions and centroid shifts characterized future spatial responses. Five-fold spatial block cross-validation yielded mean AUC, TSS, and Kappa values of 0.9867–0.9944, 0.8247–0.8727, and 0.4345–0.7676, respectively. BIO4 and BIO16 were influential predictors across most species. The cold-tolerant pair generally showed increases in suitable habitat area and northward centroid shifts. The cultivated pair exhibited contrasting responses, with substantial habitat losses for A. chinensis under late-century SSP585 and scenario-dependent gains and losses for A. deliciosa. A. eriantha remained relatively stable under most scenarios, whereas A. latifolia showed habitat expansion across all scenarios. All three pairs exhibited substantial niche overlap, but niche equivalency was rejected by both Schoener’s D and Warren’s I for the cultivated and warm-humid pairs, and only by Schoener’s D for the cold-tolerant pair. By showing that ecological or taxonomic similarity and substantial niche overlap do not necessarily correspond to parallel future spatial responses, this paired-comparison framework highlights the importance of evaluating species-specific responses to climate change. The projections provide conditional regional estimates of environmental suitability within China under the selected climate model and SSP scenarios.