The role of intraspecific trait variability and soil properties in community assembly during forest secondary succession
The role of intraspecific trait variability and soil properties in community assembly during forest secondary succession
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森林次生演替过程中种内性状变异和土壤特性在群落组装中的作用
DOI：
10.1002/ecs2.2940
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发表时间：
2019-11-01
期刊：
影响因子：
2.7
通讯作者：
Liu, Xiao
中科院分区：
文献类型：
--
作者：
Chai, Yongfu;Dang, Han;Liu, Xiao
基于特征的方法应用于社区集会，在理解社区动态背后的驱动因素方面取得了相当大的进步。然而，物种对环境条件的反应是以性状为基础的，种内性状变异(ITV)在群落演替过程中的作用尚未得到详细研究。在这里，我们探索了环境条件对植物性状组成的影响，并测试了ITV在理解中国黄土高原长期森林演替过程中的组装过程中的作用。在6个演替阶段建立了30个样地，对210种植物的15个功能性状进行了测定。计算了考虑和不考虑ITV的每个社区的Rao二次熵，并与随机期望进行比较，以评价社区的功能结构。采用结构方程模型研究了土壤非生物因子对群落功能结构的影响。群落功能结构由早期的随机格局向后期的过度分散格局转变，主要受株高和种子质量生态位分化的驱动。相反，在整个演替过程中，大多数化学和结构性状的群落功能结构表现出中性但不断增加的聚集性。我们发现，考虑种内变异并不会导致对沿演替梯度的组装过程的误读；考虑种内变异只会增加最新高潮群落的特征差异。土壤NH4-N是影响演替过程中群落功能结构和植被指数的一个特别重要的因子。我们的结果表明，在长期的森林演替过程中，主导的集聚机制从随机过程转变为确定性过程，以及强烈的环境改造，驱动了群落的集聚。在半干旱生态系统(如黄土高原)的局部次生林演替过程中，忽略ITV(除植物高度外)可能是可以接受的群落集聚。
Trait-based approaches applied to community assembly have led to a considerable advance in understanding the drivers that underlie community dynamics. However, species respond to environmental conditions based on traits, and the role of intraspecific trait variability (ITV) in community assembly during succession has not been studied in detail. Here, we explored the effects of environmental conditions on plant trait composition and tested the role of ITV on understanding the assembly processes throughout a longterm forest succession on the Loess Plateau of China. Thirty plots were established across six successional stages, and 15 functional traits of 210 species were measured. Rao's quadratic entropy of each community with and without accounting for ITV was calculated and then compared with random expectation to evaluate the community functional structure. A structural equation model was used to determine the effects of soil abiotic factors on community functional structure. Community functional structure based on multiple traits transitioned from a stochastic pattern in the early community to a significantly overdispersed pattern in the latest climax community, mainly driven by the increasing niche differentiation of plant height and seed mass. In contrast, community functional structure for most chemical and structure traits showed a neutral but increasing clustering pattern throughout succession. We found that consideration of intraspecific variability did not result in the misreading of the assembly process along a successional gradient; consideration of intraspecific variability only increased the divergence of traits for the latest climax community. Soil NH4-N was an especially important factor that influenced community functional structure and ITV during succession. Our results suggest a change in the dominant assembly mechanism from stochastic to deterministic processes and a strong environmental modification that drives community assembly during a long-term forest succession. Ignoring ITV (except for plant height) may be acceptable in understanding community assembly along a local secondary forest succession in a semiarid ecosystem, such as the Loess Plateau.