A review on the elevational patterns of plant species diversity

Abstract

Patterns of biodiversity along environmental gradients is one of the basic issues in the biodiversity studies. The elevational gradient incorporates multiple resource gradients which vary continuously in different fashions. As patterns along environmental gradients are significantly scaledependent, we reviewed plant diversity patterns along the elevational gradient in different scales: α diversity, β diversity and γ diversity, as well the factors which maintain these patterns. At the local scale, there is no fixed elevational pattern for herb species richness. For woody plants, the monotonic decrease of species richness as elevation increases is thought to be a general pattern, yet other patterns exist. The decrease of β diversity with increasing elevation has been observed in different ecosystems. Species richness in different elevational bands exhibits two different patterns, monotonic decrease and humpshaped pattern along the elevational gradient.