The effect of environmental filtering on variation in functional diversity along a tropical elevational gradient
The effect of environmental filtering on variation in functional diversity along a tropical elevational gradient
复制标题
环境过滤对热带海拔梯度功能多样性变化的影响
DOI：
10.1111/jvs.12786
复制
发表时间：
2019-08-16
影响因子：
2.8
通讯作者：
Xu, Yue
中科院分区：
文献类型：
--
作者：
Ding, Yi;Zang, Runguo;Xu, Yue
海拔梯度包含多种资源或非资源压力源，但这些不同的梯度如何驱动功能结构尚不清楚。通过对热带海拔1400 m的非生物变量和功能性状的采样，探讨了以下问题：(a)树木群落的功能多样性和功能结构如何随环境变化；(b)不同的组合如何沿海拔梯度变化？地理位置：位于中国南部海南岛上的热带森林。方法在海拔180 ~ 1521 m范围内建立60个0.05 ha样带。我们记录了所有木质茎>= 5 cm dbh（胸高直径），并测量了每个样带的功能性状和土壤特征。利用回归模型探讨了非生物变量、功能多样性和功能性状群落加权平均值（CWM）沿海拔梯度的变化规律。沿着海拔梯度的组装与一个null模型进行了比较，该模型打乱了物种的身份。结果比叶面积、叶片磷、氮含量的功能丰富度（FRic）、功能离散度（FDis）和功能离散度（CWMs）随海拔升高而降低，且随非生物变量主成分分析第一轴（PCA1）的变化而降低。叶片干物质含量和最大高度的CWM随海拔变化不显著，但最大高度的CWM随海拔变化而增加。随着海拔升高和PCA1的增加，FRic和FDis的发散性减弱，趋同性增强，这与零模型下的预测结果不同。结论在低海拔地区，环境过滤会选择具有获取策略和保守策略的物种，而在高海拔地区，环境过滤只选择具有保守策略的物种。不同胁迫源、资源（水）和非资源（温度和pH）的存在导致不同功能结构的群落组合不同。
Questions Elevational gradients encompass multiple resource or non-resource stressors, but how these different gradients drive functional structure is not well understood. Abiotic variables and functional traits were sampled along a 1,400 m tropical elevational gradient to answer the following questions: (a) how do the functional diversity and functional structure of tree communities change with environment; (b) how does the different assembly vary along the elevational gradient? Location Tropical forests on Hainan Island, South China. Methods Along an elevational gradient from 180 m to 1,521 m, sixty 0.05-ha transects were established. We recorded all woody stems >= 5 cm dbh (diameter at breast height) and measured functional traits and soil features in each transect. The patterns of abiotic variables, functional diversity and community-weighted mean (CWM) of functional traits were explored along the elevational gradient by using a regression model. The assembly along the elevational gradient was compared with a null model that shuffled species identities. Results The functional richness (FRic), functional dispersion (FDis) and CWMs of specific leaf area, leaf phosphorus and nitrogen content decreased with increasing elevation, as well as with the first axis of the principal components analysis (PCA1) of abiotic variables. The CWMs of leaf dry matter content and maximum height did not show significant change with elevational change, but the CWM of maximum height increased with PCA1. Both FRic and FDis became less divergent and more convergent with increasing elevation and with PCA1, which differed from the predicted outcome under the null model. Conclusions All these observations support that environmental filtering selects species with either acquisitive or conservative strategies at low elevations, but it only selects species with conservative strategies at high elevations. The presence of different stressors, resources (water) and non-resources (temperature and pH) leads to distinct community assemblages with different functional structures.