Hierarchical organization via a facilitation cascade in intertidal cordgrass bed communities
Hierarchical organization via a facilitation cascade in intertidal cordgrass bed communities
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DOI：
10.1086/510603
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发表时间：
2007-02-01
影响因子：
2.9
通讯作者：
Bertness, Mark D.
中科院分区：
文献类型：
--
作者：
Altieri, Andrew H.;Silliman, Brian R.;Bertness, Mark D.
最近有人提出，许多社区是由一个层次的相互作用，其中基础物种的促进作用是至关重要的。我们通过调查新英格兰鹅卵石海滩上积极互动的组织，对这一假设进行了第一次明确的实验检验。在这个潮间群落中，波浪产生的基底不稳定性和太阳应力在很大程度上限制了海洋生物对灯心草床的庇护。绳草，可以建立和坚持没有其他基础物种的帮助下，促进了密集的居民聚集（e。例如，在一个实施例中，贻贝、蜗牛、海藻），其根/根茎稳定基质，浓密的树冠阻挡波浪并提供阴凉。在绳草床群落内，肋贻贝进一步提高了其他物种的物理条件和密度（e。例如，在一个实施例中，片足类动物，藤壶）通过提供裂缝空间和硬基板。我们的结论是，大米草床群落是分层组织：次级相互作用（e。例如，在一个实施例中，促进肋贻贝）发挥关键作用的组合依赖于初级促进独立成功的基础物种灯心草。我们的研究结果确定紧急的间接积极的相互作用的形式，促进级联，保护具有广泛的影响，并帮助统一现有的社区组织模型，开发没有考虑积极的相互作用的基本作用。
It has recently been proposed that many communities are structured by a hierarchy of interactions in which facilitation by foundation species is of primary importance. We conducted the first explicit experimental test of this hypothesis by investigating the organization of positive interactions on New England cobblestone beaches. In this midintertidal community, wave-generated substrate instability and solar stress largely limit marine organisms to the shelter of cordgrass beds. Cordgrass, which can establish and persist without the aid of other foundation species, facilitates a dense assemblage of inhabitants ( e. g., mussels, snails, seaweeds) with roots/rhizomes that stabilize substrate and a dense canopy that baffles waves and provides shade. Within the cordgrass bed community, ribbed mussels further enhance physical conditions and densities of other species ( e. g., amphipods, barnacles) by providing crevice space and hard substrate. We conclude that cordgrass bed communities are hierarchically organized: secondary interactions ( e. g., facilitation by ribbed mussels) play a key role within an assemblage dependent on primary facilitation by the independently successful foundation species cordgrass. Our results identify emergent indirect positive interactions in the form of facilitation cascades, have broad implications for conservation, and help unify existing models of community organization that were developed without considering the fundamental role of positive interactions.