Within the coastal marine environment, the increased presence of artificial habitat can have negative impacts on the functioning of marine communities. Artificial structures provide a novel, hard surface for the colonization and growth of a variety of marine species and disproportionally favor introduced species. With the global rise in hardened shorelines, it is imperative to examine the ecological processes that occur within these habitats to those occurring in natural habitats. Here, we compared habitat differences in fouling community composition of different successional ages as well as the impact of predation on those communities. Specifically, we investigated how communities differed with respect to natural (seagrass beds) and artificial (docks) habitats and then exposed previously caged communities to predators to examine prey-specific effects within each habitat and on different aged communities. We found that habitat was a good predictor of community structure including both total species richness and introduced species richness higher in artificial habitats. We expected predators to increase available space allowing increased species co-existence, however, this was not the case. Predators in both habitats reduced richness despite having a strong impact on the percent cover of dominant groups. Predators also reduced introduced species richness, particularly in artificial habitats. Artificial structures are an important pathway of success for introduced species and results here show the importance of biotic resistance within these habitats, potentially limiting the spread of introduced species into natural habitat. Overall, species found within the different habitats could be predicted based on life history traits and predators did not increase the similarity of communities between habitats though still acted in a comparable way, reducing the dominant groups.

在沿海海洋环境中，人工栖息地数量的增加会对海洋社区的功能产生负面影响。人工结构为各种海洋物种的定殖和生长提供了新颖而坚硬的表面，并成比例地有利于引入的物种。随着全球硬化海岸线的增加，必须检查这些生境中发生的生态过程与自然生境中发生的生态过程。在这里，我们比较了不同演替年龄的污损群落组成中的栖息地差异，以及捕食对这些群落的影响。特别，我们调查了社区在自然（海草床）和人工（码头）栖息地方面的差异，然后将先前笼养的社区暴露于捕食者中，以研究每个栖息地内以及对不同年龄社区的猎物特有影响。我们发现，栖息地可以很好地预测群落结构，包括人工栖息地的总物种丰富度和较高的引进物种丰富度。我们预计捕食者会增加可用空间，从而增加物种的共存性，但是事实并非如此。尽管这两种栖息地的捕食者都对优势种群的覆盖率产生了很大影响，但它们的丰富度却降低了。捕食者还减少了引进物种的丰富度，特别是在人工栖息地。人工结构是引进物种成功的重要途径，这里的结果表明了这些生境中生物抗性的重要性，这可能限制了引进物种向自然生境的传播。总体而言，可以根据生活史特征预测在不同栖息地内发现的物种，尽管掠食者仍以类似的方式起作用，但它们并未增加栖息地之间的群落相似性，从而减少了优势种群。