Conclusions
In the Gyirong Valley of the central Himalayas, range size of vascular
plants across different life form and biogeographical affinities were
found increasing uniformly along the elevational gradient, which were in
accordance with the prediction of Rapoport’s rule. Climate, especially
contemporary climate, was the main driver for the increasing trends of
vascular plants range. Both the climate variability hypothesis and the
mean climate condition hypothesis were supported in explaining the
elevational variation of range size. Our results reinforce previous
notion that Rapoport’s rule applies to where the influence of climate is
most pronounced. Such a climate-driven variations of range size call for
close attention to the impact of climate change, which has been
implicated in range contractions and even extinction of many taxa.