ABSTRACT: Foundation species are vital to the maintenance of biodiversity and ecosystem functioning in many systems. On rocky shores, rockweeds (large brown algae in the Order Fucales) have the potential to provide habitat and ameliorate stress for mobile invertebrates. To determine the relative role of 2 rockweeds (Silvetia compressa and Pelvetiopsis spp.) as foundation species at sites along a latitudinal gradient, we conducted observational surveys and then initiated a 12 mo removal experiment. We found that richness and abundance of mobile invertebrates declined over time when rockweeds were removed, but only at the southernmost site. In contrast, at our other sites, there was no change in the richness and abundance of mobile invertebrates following rockweed removal. At the southern site, rockweeds played an important role in maintaining mobile invertebrate diversity. At our central and northern sites, rockweeds were less important in maintaining the diversity of mobile invertebrates. At these sites, alternative species, including bladed and branching taxa in the genera Mastocarpus, Mazzaella, Corallina, and Endocladia, co-occur with rockweeds and can buffer the system against their loss. However, these alternative foundation species are rare to absent at the southern site, potentially due to greater physical stress. The loss of rockweed foundation species, which are declining at our southern site, can have cascading effects by causing local co-extinctions of associated species. This study highlights the importance of foundation species, especially in areas where their functional redundancy is low, and how the loss of foundation species can alter diversity, leading to potential changes in ecosystem functioning.

中文翻译：

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功能冗余缓冲移动无脊椎动物以防止岩石海岸基础物种的损失

摘要：基础物种对于维持许多系统中的生物多样性和生态系统功能至关重要。在多岩石的海岸上，岩藻（Order Fucales 中的大型褐藻）有可能为移动的无脊椎动物提供栖息地和缓解压力。确定 2 种岩藻（Silvetia compressa和Pelvetiopsis）的相对作用spp.) 作为沿纬度梯度地点的基础物种，我们进行了观察调查，然后开始了 12 个月的移除实验。我们发现，当岩草被移除时，移动无脊椎动物的丰富度和丰度会随着时间的推移而下降，但仅限于最南端的地点。相比之下，在我们的其他地点，去除岩草后移动无脊椎动物的丰富度和丰度没有变化。在南部遗址，岩藻在维持移动无脊椎动物多样性方面发挥了重要作用。在我们的中部和北部站点，岩草在维持移动无脊椎动物的多样性方面不太重要。在这些地点，替代物种，包括Mastocarpus、Mazzaella、Corallina属的叶片和分枝类群和Endocladia与岩草共生，可以缓冲系统以防止它们的损失。然而，这些替代基础物种在南部地区很少见，可能是由于更大的物理压力。在我们南部地区正在减少的岩藻基础物种的丧失可能会导致相关物种在当地共同灭绝，从而产生连锁效应。这项研究强调了基础物种的重要性，尤其是在其功能冗余度较低的地区，以及基础物种的丧失如何改变多样性，从而导致生态系统功能的潜在变化。