Changes in species' elevational range limits and range sizes uncovered by herbarium specimens

Ongoing global warming drives species range shifts along latitudinal and elevational gradients, but many terrestrial species cannot keep pace with rapid climate change. The changes in species' elevational range sizes are critical for assessing their response to climate change and extinction risk. The growing digitization of herbarium specimens provides a valuable opportunity to understand species range dynamics. We explore the elevational range size and the upper and lower range changes of plants in 29 mountains of China and compare the determining factor affecting the shifts in elevational range size. The upper range limits of plants shifted downward 15 m, while the lower range limits shifted upward 34 m on average. Plants tended to contract their elevational range size, with species occurring at middle/high elevations showing greater average reductions. Shifts in elevational range size are related to changes in upper and lower range limits. Temperature change and species' thermal adaptations are the primary drivers of these shifts, although the changes in upper and lower range limits are driven by different factors. Large-scale digitized specimens can improve our understanding of dynamic changes in range size and provide valuable resources to support biodiversity conservation.