Altitudinal patterns of plant species richness on the ridge of the Baekdudaegan Mountains, South Korea: area and mid-domain effect

Abstract

We studied patterns of plant species richness along an altitudinal gradient on the ridge of the Baekdudaegan Mountains, South Korea. The roles of area and the mid-domain effect were evaluated in relation to the observed altitudinal richness patterns. Plant data were collected at 1100 plots along a 200–1900 m asl altitudinal gradient on the ridge. A total of 802 plant species from 97 families and 342 genera were found. The altitudinal patterns of plant species richness along the ridge show clear hump-shaped patterns, even though the absolute altitudes of the richness peaks varied somewhat among the plant groups. Area and the mid-domain effect were the primary drivers in simple regression models, whereas the effect of area disappeared under the presence of the mid-domain effect from multiple regression analysis. Because area and the mid-domain effect are highly correlated, it is possible to substitute the area effect with the mid-domain effect in the multiple regression model. Our results suggest the mid-domain effect is a robust predictor for observed species richness along altitudinal gradients and is substantial in explaining altitudinal richness patterns. Further study on climatic factors (e.g., mean annual precipitation and temperature), as well as factors related to evolutionary history (e.g., niche conservation) with spatial-related factors such as area and the mid-domain effect, might afford a better understanding of the factors controlling the altitudinal distribution of plant communities from a macroecological perspective.