Effects of a nonnative habitat-forming species on mobile and sessile epifaunal communities
Effects of a nonnative habitat-forming species on mobile and sessile epifaunal communities
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非本地生境形成物种对移动和固着的表层动物群落的影响
DOI：
10.3354/meps08341
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发表时间：
2010
影响因子：
2.5
通讯作者：
R. Coates
中科院分区：
文献类型：
--
作者：
K. Sellheim;J. Stachowicz;R. Coates
原生和外来无根无脊椎动物可以作为生境调节剂，影响相关的地外群落的多样性和组成。理论和实证研究表明，生境结构复杂性越高，层外物种的丰度、丰富度和多样性越高。我们通过比较最近引入的结构复杂的苔藓虫——水孢子虫（Watersipora subtorquata）与主要底物、其他栖息地调节剂（被囊动物和贻贝）以及结构相似的模拟物的相关底外群落，评估了其影响。水孢菌的群落组成与其他处理不同，但水孢菌的物种丰富度和多样性显著高于其他处理。多毛类蠕虫在流动群落组成和多样性上的差异主要由多毛类蠕虫驱动，其中水虫的丰度和多样性更高。甲壳类动物虽然同样丰富，但在不同的处理中分布更均匀。不同处理下的无根地表层群落的丰富度和丰度差异不大，这表明尽管水孢子为定植提供了充分补偿其利用的主要底物的生物源表面，但相对于不太复杂的生境调节剂，其高结构复杂性并不对应于无根地表层丰度的增加。我们的研究结果表明，外来物种的中性或促进作用可能是常见的；一个新的生境形成物种对脚底动物群落影响的强度和方向取决于它所提供的资源的质量、生境形成物种与脚底动物之间的生态相互作用的强度、脚底动物对生境的偏好，以及生境是否是一个特定物种或类群的限制性资源。
Native and exotic sessile invertebrates can act as habitat modifiers and influence the diversity and composition of associated epifaunal communities. Theory and empirical research pre- dict that greater habitat structural complexity will generally result in higher abundance, richness, and diversity of epifaunal species. We evaluated the impact of a recently introduced, structurally complex bryozoan, Watersipora subtorquata, by comparing its associated epifaunal communities with those of primary substrate, other habitat modifiers (tunicates and mussels), and structurally sim- ilar mimics. Community composition differed between Watersipora and other treatments for both mobile and sessile epifaunal communities, but species richness and diversity were significantly higher on Watersipora for mobile animals only. Differences in mobile community composition and diversity were driven by polychaete worms, which were found in greater abundance and higher diversity in Watersipora. Crustaceans, although equally abundant, were more evenly distributed across treatments. Sessile epifaunal communities differed little in richness or abundance among treatments, suggesting that while Watersipora provides biogenic surfaces for colonization that adequately compensate for the primary substrate it exploits, its high structural complexity does not correspond to an increase in sessile epifaunal abundance relative to less complex habitat modifiers. Our results suggest that neutral or facilitative effects of exotic species may be common; the strength and direction of the impact of a novel habitat-forming species on epifaunal communities will depend on the quality of the resource it provides, the strength of ecological interactions between habitat- forming species and epifauna, epifaunal habitat preferences, and whether habitat is a limiting resource for a particular species or group.