Spatiotemporal Dynamics of Suitable Habitat for Weigela florida.

Global climate change profoundly impacts the geographical distribution patterns and evolutionary dynamics of plants. As a vital ornamental and ecological shrub native to the temperate regions of the Northern Hemisphere, the wild germplasm resources of Weigela florida are facing dual threats from habitat fragmentation and climate warming. To elucidate the biogeographical mechanisms underlying the species' responses to climate change and to formulate scientific conservation strategies, this study simulated the spatiotemporal dynamics of suitable habitats for W. florida across key historical periods spanning the Late Pliocene (~3.3 million years ago), Quaternary (~2.58 million years ago), the current period, and future climate scenarios using an optimized Maximum Entropy ecological niche model, and further tracked the migration trajectories of its spatial centroids. The results indicate that precipitation conditions, dry-season temperatures, and temperature seasonality are the dominant environmental factors limiting the distribution of wild W. florida. During the glacial-interglacial cycles, the area of its suitable habitat fluctuated significantly. Notably, the Korean Peninsula and the southern part of Northeast China maintained high habitat suitability across all geological historical periods, serving as long-term stable Quaternary glacial refugia for the species. Under various future climate scenarios, the total suitable habitat area of W. florida generally exhibits a shrinking trend, with habitat loss primarily concentrated at the western and southern edges of its distribution range. In the future, its spatial centroid shows a significant tendency to migrate towards higher latitudes (northeastward) to track suitable climatic niches. This study clarifies the macroscopic driving mechanisms behind the habitat dynamics of wild W. florida, providing critical spatial planning guidance for the refined evaluation and long-term sustainable utilization of its germplasm resources.