Small mammal species richness and turnover along elevational gradient in Yulong Mountain, Yunnan, Southwest China

Understanding the species diversity patterns along elevational gradients
is critical for biodiversity conservation in mountainous regions. We
examined the elevational patterns of species richness and turnover, and
evaluated the effects of spatial and environmental factors on non-volant
small mammals (hereafter ‘small mammal’) predicted a priori by alternative
hypotheses [Mid-domain effect (MDE), species area relationship (SAR),
energy, environmental stability and habitat complexity)] proposed to
explain the variation of diversity. We designed a standardized sampling
scheme to trap small mammals at ten elevational bands across the entire
elevational gradient on Yulong Mountain, Southwest China. A total of 1808
small mammals representing 23 species were trapped. We observed the
hump-shaped distribution pattern of the overall species richness along
elevational gradient. Insectivores, rodents, large-ranged species and
endemic species richness showed the general hump-shaped pattern but peaked
at different elevations, whereas the small-ranged species and endemic
species favored the decreasing richness pattern. The MDE and the energy
hypothesis were supported, whereas little support was found for the SAR,
the environmental stability hypothesis and the habitat complexity.
However, the primary driver(s) for richness patterns differed among the
partitioning groups, with NDVI (the normalized difference vegetation
index) and MDE were the most important variables for the total richness
pattern. Species turnover for all small mammal groups increased with
elevation, and it supported a decrease of community similarity with
elevational distance. Our results emphasized for increased conservation
efforts in the higher elevation regions of the Yulong Mountain.