Changing gears during succession: shifting functional strategies in young tropical secondary forests
Changing gears during succession: shifting functional strategies in young tropical secondary forests
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DOI：
10.1007/s00442-015-3339-x
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发表时间：
2015-09-01
期刊：
影响因子：
2.7
通讯作者：
van Breugel, Michiel
中科院分区：
文献类型：
--
作者：
Craven, Dylan;Hall, Jefferson S.;van Breugel, Michiel
对资源可获得性的适应在很大程度上决定了环境条件下群落组成的格局。在本研究中，我们研究了功能组成的变化在多大程度上解释了热带次生林幼林在演替最活跃的阶段(0-20年)基于特征的功能策略的变化。通过对55种木本植物(n=875-1,761株)的群落7个功能性状的群落加权平均分析，确定了51个次生林样地2个径级的功能组成。在森林结构的演替梯度上，从获取资源到保护资源的职能战略发生了重大和一致的转变。在演替过程中，叶片韧性和成株大小显著增加，而净光合能力(A质量)显著下降。A(质量)和木材密度的大小类内功能策略的变化也支持这样的假设，即功能组成的变化是由沿演替梯度的环境条件塑造的。总体而言，与植物表现的不同方面有关的“硬”功能性状，如A(质量)和叶片韧性，对森林结构的演替变化表现出比“软”性状更敏感的表现，如叶质量面积和叶干物质含量。我们的结果还表明，与以前的土地利用历史、扩散限制和非生物因素有关的随机过程解释了功能组成的变化，而不是归因于功能策略的确定性变化。需要关于种子传播媒介以及距离和景观结构的进一步数据，以改进目前热带次生林演替的机械模型。
Adaptations to resource availability strongly shape patterns of community composition along successional gradients in environmental conditions. In the present study, we examined the extent to which variation in functional composition explains shifts in trait-based functional strategies in young tropical secondary forests during the most dynamic stage of succession (0-20 years). Functional composition of two size classes in 51 secondary forest plots was determined using community-weighted means of seven functional traits, which were intensively measured on 55 woody plant species (n = 875-1,761 individuals). Along the successional gradient in forest structure, there was a significant and consistent shift in functional strategies from resource acquisition to resource conservation. Leaf toughness and adult plant size increased significantly, while net photosynthetic capacity (A (mass)) decreased significantly during succession. Shifts in functional strategies within size classes for A (mass) and wood density also support the hypothesis that changes in functional composition are shaped by environmental conditions along successional gradients. In general, 'hard' functional traits, e.g., A (mass) and leaf toughness, linked to different facets of plant performance exhibited greater sensitivity to successional changes in forest structure than 'soft' traits, such as leaf mass area and leaf dry matter content. Our results also suggested that stochastic processes related to previous land-use history, dispersal limitation, and abiotic factors explained variation in functional composition beyond that attributed to deterministic shifts in functional strategies. Further data on seed dispersal vectors and distance and landscape configuration are needed to improve current mechanistic models of succession in tropical secondary forests.