Abstract
The objective of this research was to study the relation between species richness and topography in the middle sub-tropical area of Eastern China. A species richness survey was conducted along altitude in Kaihua County, Zhejiang Province, Eastern China. Topographic variables, such as altitude, slope, aspect, terrain roughness, relief degree and the topographical wetness index, were extracted from the digital elevation model. The Generalized Additive Model (GAM), the linear model and the quadratic model were used to fit response curves of species richness to topographic variables. The results indicated that altitude and the topographical wetness index have a significant relation to species richness. Species richness has a unimodal response to altitude and a linear response to the topographical wetness index. However, no significant correlations were observed between slope, aspect and species richness. The predicted species richness by GAM is significantly correlated with the observed species richness, whereas the prediction error tends to increase with the increment of species richness. This study furthered insights into the relationship between topography and plants’ diversity in the middle sub-tropical area of Eastern China.
Highlights
Species richness is one of the important biodiversity measures [1]
Instead of incorporating topographic metrics as predictors to analyze the relationship between species richness and topography, geodiversity was used as a comprehensive indicator to represent environmental heterogeneity [11,12,13]
Geodiversity was considered as an important correlate of biodiversity at regional and landscape scales [11,12,14] and contributed more than topographic variables accounting for species richness [13], the limitation of data availability influenced the widespread application of geodiversity in biodiversity and ecology research
Summary
Species richness is one of the important biodiversity measures [1]. The relation between species richness and the influencing factors has always been one of the focuses in biodiversity and ecology research [1,2]. In this research, based on the generalized additive model, and the digital elevation model, we studied the relation between the species richness and the topographic variables of evergreen broad-leaf forest in Kaihua County and predicted the spatial distribution of species richness. This will help us to explore the characteristics of the evergreen broad-leaf forest in the middle sub-tropical area of Eastern China.
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