Community assembly and functional diversity along succession post-management
Community assembly and functional diversity along succession post-management
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DOI：
10.1111/1365-2435.12257
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发表时间：
2014-10-01
影响因子：
5.2
通讯作者：
Balvanera, Patricia
中科院分区：
文献类型：
--
作者：
Bhaskar, Radika;Dawson, Todd E.;Balvanera, Patricia
1.尽管演替理论的广泛发展，很少有实证研究评估现有的模型是否适用于人类修改的景观。季节性干燥的热带森林正在经历广泛的转变，并代表了一个重要的系统，以评估在一个演替框架，推断机制，形成组装次生林后管理。2.我们使用了一个功能特性为基础的方法来评估社区组装机制的变化，沿着演替梯度在次生林的不同阶段，放弃养牛活动。附近的原始森林作为一个未受干扰的比较。我们评估是否重新组装进行与现有的理论，在早期的演替阶段，通过栖息地过滤，导致减少性状范围，并通过竞争性排斥在后期阶段，导致性状均匀度增加。使用三个正交性状和两个功能多样性指数，我们测试的证据组装机制沿着资源轴，可能是特别重要的干旱森林系统，栖息地过滤和竞争性排斥的动态变化，和潜在的遗产管理的影响。3.我们发现很少支持的进展，从栖息地过滤竞争排斥，与特定的叶面积和多变量功能丰富度的分散模式除外。在大多数阶段，水的供应可能是物种分类的基础，如木材密度的范围减少所证明的，并且可能是对干旱森林集合特别重要的资源。早期的演替阶段显示出意想不到的模式低均匀度，这可能是由于初始的立场组成，包括残余物和重新发芽，典型的干燥的森林物种的再生策略。除了影响初始条件，管理遗产是明显的，在先进的次生林，不同的范围，甚至分散，功能丰富的原始森林，这表明不同的组装机制的运作。4.偏离预期表明，需要重新评估演替模式，包括管理遗产的影响，社区大会机制的运作，在人类改造的景观，以及特点，区分湿，干森林动态。
1. Despite extensive development of successional theory, few empirical studies have evaluated whether existing models are applicable to human-modified landscapes. Seasonally dry tropical forests are experiencing widespread transformation, and represent a critical system to assess in a successional framework to infer the mechanisms that shape assembly of secondary forests post-management. 2. We used a functional trait-based approach to assess changes in community assembly mechanisms along a successional gradient in secondary dry forests of varying stages following abandonment of cattle activity. Nearby old-growth forests served as an undisturbed comparison. We evaluated whether re-assembly proceeded consistent with existing theory, in early successional stages via habitat filtering, leading to reduced trait range, and via competitive exclusion in later stages, leading to increased trait evenness. Using three orthogonal traits and two functional diversity indices we tested for evidence of assembly mechanisms along resource axes that may be particularly important to dry forest systems, dynamic changes in habitat filtering and competitive exclusion, and potential legacy effects of management. 3. We found little support of a progression from habitat filtering to competitive exclusion, with the exception of dispersion patterns for specific leaf area and multi-variate functional richness. Water availability may underlie species sorting in most stages, as evidenced by range reduction in wood density, and might be a resource particularly important to dry forest assembly. Early successional stages displayed an unexpected pattern of low evenness, which may be due to initial stand composition including remnants and resprouts, a regeneration strategy typical to dry forest species. Beyond influencing initial conditions, management legacy was apparent in advanced secondary forests, which differed in range, even dispersion, and functional richness from old-growth forests, suggesting the operation of different assembly mechanisms. 4. The departures from expectations suggest the need to re-assess successional models to include effects of management legacies on the operation of community assembly mechanisms in human-modified landscapes, as well as characteristics that distinguish wet and dry forest dynamics.