The Effects of Spatial and Climatic Factors on Woody Plant Richness along an Extensive Altitudinal Gradient in South Korea

Abstract

This study was conducted to clarify the richness patterns of woody plants along a temperatealtitudinal gradient on the Baekdudaegan ridge, South Korea. The effects of the spatial andclimatic factors on the observed altitudinal richness patterns were evaluated. We also testedRapoport’s altitudinal effect, which relates the distribution of a species’ altitudinal ranges to thepatterns in species richness. Woody plant data were collected from 1100 plots on theBaekdudaegan ridge. A total of 248 woody plant species from 47 families and 99 genera werefound. The altitudinal pattern of the woody plant species richness on the Baekdudaegan ridgeexhibited a clear hump-shaped pattern with a peak around 800 m. Spatial factors(mid-domaineffect and area) were the primary drivers in the simple linear models, whereas the climaticfactors(mean annual precipitation and temperature) had lower explanatory power. Multiple linearregression analysis revealed that the combined interaction between spatial and climatic factorsaffected the altitudinal richness patterns of the overall woody plants. Furthermore, the spatialand climatic factors were more important for large- and small-ranged woody plants, respectively. The results of Stevens’ method and the midpoint method do not support Rapoport’s altitudinaleffect. The results suggest that a combined interaction between spatial and climatic factorsinfluences the richness pattern of the total woody plant species. Furthermore, the relativeimportance of these factors depends on the range size of the woody plants species along analtitudinal gradient on the ridge of the Baekdudaegan ridge.