Light availability, soil phosphorus and different nitrogen forms negatively affect the functional diversity of subtropical forests

Abstract

Understanding the relationship between functional diversity (FD) and species diversity changes and the effects of environmental factors on FD during succession is useful to improve forest management, conservation and restoration strategies. In this study, we measured 9 environmental factors related to light availability, soil water content and nutrients, and 19 leaf functional traits related to leaf light and nutrient utilization, growth and defense, water-use efficiency, and leaf respiration strategies in the dominant species during subtropical forest succession in southern China. Logarithmic function analysis and linear mixed model were used to explore the relationships between FD and species diversity and between FD and environmental factors. The results showed that FD and species diversity were not linearly correlated during succession. The light availability (represented by leaf area index), soil phosphorus, and different nitrogen forms were negatively related to the FD, suggesting these factors were the main environmental factors affecting FD during succession in the subtropical forest. By dividing FD into components corresponding to the diversity of different plant strategies, this study improves our understanding of the roles of light availability and soil nutrients in plant community functional structure, and provides useful information for forest conservation and restoration.