Effects of topography and stand structure of warm temperate deciduous broad-leaved forest on understory herb diversity in Donglingshan, Beijing
Aim: Topographic and stand structure are important factors affecting species diversity of understory communities. Our objective was to explore the effects of different topographic factors and forest stand structure on the species diversity of herbaceous plants in a warm temperate deciduous broad-leaved forest.
Methods: Based on the survey data of 450 1 m × 1 m herbaceous plots in the 20 ha Donglingshan forest dynamics plot, Beijing, we used species richness index, Shannon-Wiener diversity index, Simpson dominance index and Pielou evenness index as the indicators of herbaceous species diversity to analyze the changes of each diversity index with different factors of topographic and forest stand structure. Meanwhile, we utilized Pearson correlation analysis, regression analysis, redundancy analysis (RDA), and hierarchical partitioning methods to explore the influence of topographic and forest stand structure factors on herbaceous species diversity.
Results: (1) The herbaceous Shannon-Wiener diversity index in the forest was negatively correlated with the slope aspect (P < 0.05), and the Shannon-Wiener diversity index decreased with the slope aspect (from sunny to shady slopes). The four diversity indices had no significant correlation with elevation, slope, and concavity. (2) The species richness index and Shannon-Wiener diversity index decreased with the increase in stand density and forest species richness but increased with the rise of mean DBH. The four species diversity indices were not significantly correlated with coefficient of variation of DBH (DBHcv). (3) The hierarchical partitioning method showed that environmental factors explained herbaceous species diversity as follows: stand density > DBH > DBHcv > elevation. Stand density was the main factor affecting the species diversity of herbaceous plants under the forest.
Conclusion: This study revealed the effects of different topographic factors and forest stand structure factors on the diversity of herbaceous plants in the warm temperate deciduous broad-leaved forest, and confirmed that stand density was the key factor. Our findings will contribute to the comprehensive understanding of forest biodiversity in the promotion and protection of forest ecosystem and biodiversity.
