Biodiv Sci ›› 2021, Vol. 29 ›› Issue (9): 1186-1197.DOI: 10.17520/biods.2021205

• Original Papers: Plant Diversity • Previous Articles     Next Articles

Relationship between variation of plant functional traits and individual growth at different vertical layers in a subtropical evergreen broad-leaved forest of Dinghushan

Yanpeng Li1,2, Yunlong Ni1,3, Han Xu2, Juyu Lian1,3,4,*(), Wanhui Ye1,3,4   

  1. 1 Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650
    2 Forest Ecology Research Center, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520
    3 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650
    4 Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458
  • Received:2021-05-21 Accepted:2021-08-11 Online:2021-09-20 Published:2021-09-16
  • Contact: Juyu Lian

Abstract:

Aims: Establishing the relationship between plant functional traits and community dynamics is one of the core issues of functional ecology. Previous studies have found weak evidence of a relationship between functional traits and growth rate relationships in tree communities, highlighting the evidence that functional traits often fail to predict growth rate. It is therefore essential to advance a predictive approach to functional ecology. Since functional traits vary both among species and within species, linking functional traits at the individual level with plant growth will provide a path towards a more rigorous trait-based community ecology.
Methods: Based on the data from two survey of a 1.44-ha plot and the data of six plant functional traits from 4,142 individuals in Dinghushan, the effects of plant functional traits on plant growth were analyzed at the individual level and species level. First, the varied trends of different functional traits at different vertical layers (shrub layer, subcanopy layer and forest canopy layer) were explored. Second, the intraspecific and interspecific variations of each functional trait under different vertical layers were analyzed. Finally, the effects of plant functional traits, light competition and underground competition on tree growth were quantified using a structural equation model.
Results: Results suggest that: (1) Plant functional traits at different vertical layers exhibited significant differentiation. From the shrub layer to the canopy layer, leaf area (LA), specific leaf area (SLA) and energy supply-demand index (R) decreased significantly, while leaf thickness (LT) and leaf dry matter content (LDMC) increased significantly. (2) The interspecific variation of plant functional traits at different vertical layers is greater than the intraspecific variation, and the intraspecific variation of functional traits in the canopy layer is greater than that in the shrub layer and subcanopy layer. (3) The structural equation model based on plant functional traits at an individual level produces a higher degree of explanation for growth than at the species level. Furthermore, the introduction of plant functional traits at the individual level is more conducive to improving the ability to predict individual growth at the shrub layer. (4) Light competition and underground competition indirectly affect plant growth by affecting functional traits. From the shrub layer to the canopy layer, the interactions between conspecific individual gradually weakened and the interactions between different species gradually increased.
Conclusion: Our study highlights that analyzing plant functional traits at an individual level could help to better understand plant community structure and dynamics.

Key words: vertical layer, variation of functional trait, biotic interactions, growth dynamic, structural equation model