Species elevational richness gradient and species-area relationship in mountain vegetation of Javakheti highland (Georgia)

Abstract

Elevational gradients in species richness and species-area relationships are among the most interesting patterns in ecology and biogeography. Both patterns can be characteristic of the same system; however, current knowledge of how these patterns co-exist and how we can disentangle their contributions to biodiversity structure is insufficient. In this article, we tested the effect of elevation and area on the formation of plant species diversity patterns in the forest-free Javakheti Highlands (Georgia). Samples (170 plots) were collected within elevations of 1400-3100 m, and the diversity distribution was examined in relation to altitude, available band area, and sampling. In total, 564 species from 67 families were recorded. Plant species richness was highest at mid-elevations (1900–2200 m), irrespective of area and sampling effort. This was in line with other studies from the Caucasus indicating the generality of plant elevational diversity patterns in the region. Area was not an important predictor of species richness; however, this may be considered a result of insufficient sampling. Our study shows that more research is needed to understand the effect of area on patterns of elevational biodiversity distribution.