Species pools and environmental sorting control different aspects of plant diversity and functional trait composition in recovering grasslands
Species pools and environmental sorting control different aspects of plant diversity and functional trait composition in recovering grasslands
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DOI：
10.1111/1365-2745.12617
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发表时间：
2016-09-01
影响因子：
5.5
通讯作者：
Kollmann, Johannes
中科院分区：
文献类型：
--
作者：
Conradi, Timo;Kollmann, Johannes
演替理论认为，聚集群落的分类和功能结构是由当地环境条件和区域因素的相互作用，如可用的物种池或景观配置，适度扩散。然而，这些因素的相对重要性，以及它们是否控制群落结构的不同方面，例如物种多样性或植物性状的组成，还没有得到很好的理解。这限制了对演替结果空间变化的预测。我们探讨了物种多样性和性状在恢复石灰质草原，不同的环境条件下，年龄，过去和现在的空间景观配置，以及在繁殖压力，他们收到的历史草地，有大的和功能不同的物种池的模式。混合效应模型和多模型推理被用来剖析物种多样性和功能组成的主要驱动因素。在草地重组的早期阶段，来自老草地区域物种库的物种压力是群落结构的重要决定因素，不仅对物种多样性有显著影响，而且对与资源经济相关的性状组成也有显著影响。这样的物种库效应超过了环境异质性对物种丰富度的正影响，并混淆了众所周知的多样性-环境和性状-环境关系。作为一个正交轴的社区大会，环境排序发生沿着梯度的土壤质地，区分物种根据他们的树冠高度和-在较小程度上-物候。此外，高草原周长面积比有利于专业物种丰富度，并增加了预测穷人的动物传播和风传播的物种的比例。我们提供的经验证据表明，物种池效应和当地的环境排序恢复石灰质草原的群落组装过程中操作，但它们影响植物群落结构的不同方面。此外，我们表明，地理变异的繁殖压力从大的和功能不同的源种池可以混淆多样性环境和性状环境的关系。因此，除了考虑环境因素，考虑源物种池的位置，以及它们的组成和功能特性，是一个先决条件，在演替生境的分类和功能群落结构的突发事件的稳健预测。
Succession theory argues that the taxonomic and functional structure of assembling communities is regulated by the interplay of local environmental conditions and regional factors such as available species pools or landscape configurations that moderate dispersal. Yet, the relative importance of these factors and whether they control different aspects of community structure, for example species diversity or the composition of plant traits, is not well understood. This limits predictions of spatial variation in successional outcomes. We explored patterns of species diversity and traits in recovering calcareous grasslands that varied in environmental conditions, age, past and present spatial landscape configuration, as well as in the propagule pressure they receive from historical grasslands that have large and functionally distinct species pools. Mixed-effects modelling and multimodel inference were used to dissect the leading drivers of species diversity and functional composition. Propagule pressure from the regional species pools of old grasslands during early stages of grassland re-assembly was an important determinant of community structure, with significant effects not only on species diversity but also on the composition of traits related to resource economics. Such species pool effects exceeded positive influences of environmental heterogeneity on species richness and confounded well-known diversity-environment and trait-environment relationships. As an orthogonal axis of community assembly, environmental sorting occurred along a gradient of soil texture that discriminated species according to their canopy height and - to a smaller extent - phenology. Additionally, high grassland perimeter-area ratios favoured specialist species richness and increased the proportion of species with predicted poor epizoochorous and wind dispersal.Synthesis. We provide empirical evidence that both species pool effects and local environmental sorting operate during community assembly of recovering calcareous grasslands, but that they influence different aspects of plant community structure. Further, we show that geographic variation in propagule pressure from large and functionally distinct source species pools can confound diversity-environment and trait-environment relationships. Therefore, besides accounting for environmental factors, considering the location of source species pools, as well as their compositional and functional characteristics, is a prerequisite for robust predictions of contingencies in taxonomic and functional community structure of successional habitats.