Reef-forming species play a key role creating, modifying and maintaining important habitat and their associated communities. Globally, many of these habitats are extensively fragmented but our understanding of key ecological processes is drawn from older studies performed in less degraded environments with extensive reef habitats. We tested whether proximity to habitat edges affected the persistence and functioning of fragmented intertidal mussel reefs, Mytilus edulis, at three sites in sedimentary habitats in Northern Ireland. Specifically, we quantified and compared key ecological properties in mid-habitat and edges and hypothesised that at the edges, there would be (i) larger individual mussels, (ii) lower recruitment, (iii) lower associated taxon diversity, (iv) lower biodeposition, (v) greater predation intensity and (vi) greater food availability. Additionally, we tested whether rates of functioning (e.g. organic matter accumulation) were greater in mussel patches (edge and mid-habitat) compared to sediment without mussels (vii). We did find larger mussels at the edges of patches, where there was also less organic enrichment of the sediment compared to mid-habitat (but more than areas without mussels). None of the other variables quanitifed differed consistently between the edge and mid-habitat. The lack of strong edge effects identified may be explained by the nature of the mussel habitat in this study, i.e. intrinsically greater proportion of edges compared to more extensive reefs. Our results suggest that at the scale of the reef patches in this study, edge effects were not as strong as previously thought in terms of regulating key ecological processes.

中文翻译：

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边缘效应与破碎的生物礁中的关键生态过程没有关系

形成礁石的物种在创建，修改和维护重要的栖息地及其相关社区方面发挥着关键作用。在全球范围内，这些生境中的许多生境都是零散的，但我们对关键生态过程的理解是根据在退化程度较低，拥有大量礁石生境的环境中进行的较早研究得出的。我们测试接近栖息地边缘是否影响持久性和零散的潮间带贝类礁功能，贻贝，位于北爱尔兰沉积栖息地的三个地点。具体来说，我们量化并比较了中生境和边缘的关键生态特性，并假设在边缘处，（i）贻贝个体较大，（ii）补充贻贝较低，（iii）相关分类群多样性较低，（iv）低（v）更大的捕食强度和（vi）更大的食物供应。此外，我们测试了贻贝斑块（边缘和中生境）中的功能速率（例如有机物积累）是否比没有贻贝的沉积物（vii）大。我们确实在斑块边缘发现了较大的贻贝，与中生境相比，沉积物的有机物富集也较少（但比无贻贝的地区多）。量化的其他变量在边缘和中期栖息地之间均没有一致的差异。本研究中贻贝栖息地的性质可能解释了缺乏确定的强边缘效应的原因，即与更广泛的珊瑚礁相比，内在边缘的比例更高。我们的结果表明，在这项研究中，在礁石斑块的规模上，在调节关键生态过程方面，边缘效应没有以前认为的那么强烈。