Biogeography, Climate and the Role of Direct Positive Interactions in Rocky Shoreline Communities

与竞争和消费过程相比，海洋社区中直接的积极互动所起的作用被忽视了。虽然直接的积极的相互作用被广泛地认识到，但它们很少受到社区生态学家的实验关注，并且作为一般的社区组织力量在很大程度上被忽视了。这项研究明确考察了生境改善正向相互作用在岩质潮间带群落中作为组织力量的作用，并具体探讨了生物地理和气候在决定这些相互作用的重要性方面的作用。具体地说，该项目(1)测试了以下假设：由于太阳辐射强度的可预测变化，栖息地改善、种内群体在设定初级空间持有人潮间带上限方面的重要性随着纬度的降低而增加，在海湾和河口比在开阔的海岸生境更重要。以及(2)验证了这样一种假设，即通过限制对相关生物的物理压力，高潮间带藻类树冠在构建高潮间带群落方面发挥着关键作用，而且，与种内群体利益一样，这些影响的重要性也强烈地受到生物地理和气候的影响。通过重点研究新英格兰岩石潮间带系统中正相互作用的可预测性和后果，这项工作将开始将正相互作用纳入我们对岩石海岸线和其他海洋和陆地系统的理解中。作为一项直接量化气候如何影响自然组合过程和模式的研究，Suxh也可能是探索全球气候变化对社区潜在后果的最佳工具之一。

In comparison to competitive and consumer processes, the role played by direct positive interactions in marine communities has been overlooked. While direct positive interactions are widely recognized to occur, they have received little experimental attention by community ecologists and have been largely ignored as general community organizing forces. This study explicitly examines the role of habitat ameliorating positive interactions as organizing forces in rocky intertidal communities and specifically will explore the role of biogeography and climate in dictating the importance of these interactions. Specifically, this project (1) tests the hypothesis that the importance of habitat ameliorating, intraspecific group benefits in setting the upper intertidal limits of primary spaceholders increases with decreasing latitude and is more important in bays and estuaries than in open coast habitats due to predictable variation in the intensity of solar radiation. And (2) tests the hypothesis that, by limiting physical stresses on associated organisms, high intertidal algal canopies play a keystone role in structuring high intertidal communities, and that, like intraspecific group benefits, the importance of these effects are also strongly mediated by biogeography and climate. By focusing on the predictability and consequences of positive interactions in the otherwise well studied New England rocky intertidal system, this work will begin to incorporate positive interactions into our understanding of rocky shorelines and other marine and terrestrial systems. Studies suxh as this one that directly quantify how climate can influence process and pattern in natural assemblages may also be one of the best tools available for exploring the potential consequences of global climate change on communities.