Scale-dependent spatial patterns for species diversity in a karst evergreen and deciduous broad-leaved mixed forest of northwest Guangxi
Spatial distribution patterns of species diversity and their relationships with scale are of great significance to understanding the mechanism of community species diversity formation. Here, a field survey was conducted to assess the variation in species diversity along spatial scales in a karst evergreen and deciduous broad- Leaved mixed forest, Southwest China. Based on the dataset of woody plants (DBH ≥ 1) from a 25 ha2 Plot, the spatial distribution patterns of species abundance, species richness, and Shannon-Wiener, Simpson, and Pielou's evenness indices were analyzed at six spatial scales-5 m × 5 m, 10 m × 10 m, 20 m × 20 m, 50 The results showed that spatial distributions of species diversity indices were highly heterogeneous. The variance of species diversity indices changed with spatial scale following a unimodal pattern, ie, with The maximum value at the 100 m×100 m scale. The variation of the species diversity decreased linearly with increasing scale. The Shannon-Wiener, Simpson, and Pielou's evenness indices decreased sharply at the 5 m×5 m and 20 m×20 m scales No significant positive relationship was found between species richness and abundance at scales over 50 m×50 m ( P >0.05). Our results suggest that the spatial pattern of species diversity in this evergreen and deciduous broad-leaved mixed karst forest is closely related to spatial scale. To improve the spatial variation of species diversity across spatial scales, more such studies in other similar Forest ecosystems are needed.