海南岛霸王岭热带云雾林木本植物功能性状的分异规律

研究植物功能性状的分异,有助于理解植物适应环境的方式和策略,也能为预测物种分布和环境变化提供依据。以海南霸王岭热带云雾林为对象,建立21个20 m×20 m固定样方,划分为336个5 m×5 m小样方;测定胸径在5cm以上所有乔灌木植物个体的功能性状(叶面积LA;叶干重LDW;比叶重LMA;叶绿素含量Chl;叶厚度LTh;木材密度WD)和土壤养分含量,通过方差分解分析植物功能性状在个体、种内、种间、群落水平的分异大小,探究土壤养分对功能性状分异的影响。结果表明,LA、LDW、LMA、CHl、LTh、WD在个体、种内、种间、群落水平的解释方差范围分别为0.06—0.47、0.09—0.35、0.35—0.72、0—0.07,在个体、种内、种间、群落层次上,种间水平的功能性状分异最大,而群落水平的分异最小。逐步回归分析表明,不同尺度的功能性状变化与土壤有机质、氮和磷含量都有密切关系。

Variation in woody plant functional traits of the tropical cloud forests in Bawangling, Hainan Island

The variation in plant functional traits can help us understand adaption mechanisms to different environments and predict the distribution of species and environmental changes. Twenty-one, 20 m×20 m plots were established and divided into 336, 5 m×5 m subplots in the tropical cloud forests in Bawangling, Hainan Island. Functional traits (i.e., leaf areaLA], leaf dry weightLDW], leaf mass per areaLMA], leaf chlorophyll contentChl], leaf thicknessLTh], and wood densityWD]) of all trees and shrubs with diameter at breast height over 5 cm, as well as soil nutrient contents, were measured in all plots. The magnitude of variation in each functional trait at individual plant, within-species, among-species, and community levels were assessed using a generalized linear model, whereas the relationships between soil nutrients and functional traits were examined using a stepwise linear regression. Results showed that the ranges of explained variance for LDW, LMA, CHl, LTh, LA, and WD were 0.06-0.47, 0.09-0.35, 0.35-0.72, and 0-0.07 for the individual, within-species, among-species, and community levels, respectively. This indicates that the magnitude of variation in functional traits was the highest at the among-species level and the lowest at the community level. The stepwise regression analysis showed that the changes of functional traits at all studied scales were significantly correlated with soil organic matter, nitrogen, and phosphorus.