Plant geographical range size and climate stability in China: Growth form matters

Aim: Geographical variation of range size is thought to be linked to climate seasonality and Quaternary glacial-interglacial oscillations. In addition, the importance of long-term climate stability is expected to be modulated by species' migration abilities. For plants, growth forms integrate traits that affect migration ability. Hence, we assess the relative importance of short- and long-term climate stability for range size patterns in plants and whether long-term stability is more important for more poorly migrating growth forms. Location: China. Time period: Last 21 ka. Major taxa studied: Vascular plants. Methods: A dataset including > 30,000 vascular plants was used to quantify geographical patterns of range size across China for all species and for eight growth forms separately. Spatial and non-spatial regressions with information-theoretical multi-model selection were performed to estimate the explanatory importance of climate seasonality and climate-change velocity from the Last Glacial Maximum to the present. The proportion of endemism for each growth form was also calculated. Results: Large geographical range sizes were generally observed in regions with strong climate seasonality and high climate-change velocity. The association between range size and velocity was stronger for perennial herbs and shrubs than for ferns, annual herbs, climbers and trees and stronger for small than for large trees; that is, more important for the growth forms with lower migration capacities. In line with this interpretation, growth forms strongly influenced by velocity also tend to have high proportions of endemism, which is also consistent with a relatively low ability to migrate. Main conclusions: Range size patterns of vascular plants in China are shaped by both climate seasonality and long-term climate stability, even though the region had a relatively mild influence from the Pleistocene glaciations, with a stronger influence of palaeoclimate stability on more poorly migrating groups. The differential influences of palaeoclimate stability across growth forms suggest that it needs further attention in research and management and that different growth forms are likely to respond in different ways to future climate changes.