Biotic resistance or invasional meltdown? Diversity reduces invasibility but not exotic dominance in southern California epibenthic communities
Biotic resistance or invasional meltdown? Diversity reduces invasibility but not exotic dominance in southern California epibenthic communities
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DOI：
10.1007/s10530-022-02932-1
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发表时间：
2022-10-05
影响因子：
2.9
通讯作者：
Sorte, Cascade J. B.
中科院分区：
文献类型：
--
作者：
Beshai, Ryan A.;Truong, Danny A.;Sorte, Cascade J. B.
群落的高度多样性可能会阻碍或促进外来物种的建立。生物抗性假说认为，物种丰富的群落比物种贫乏的群落更能抵抗入侵，这是由于包括更大的种间竞争在内的机制。相反，入侵熔毁假说提出，更多的外来物种多样性通过促进外来物种之间的相互作用来增加入侵能力。为了评估生物抵抗或入侵融化在组装期间对海洋群落结构的影响程度，我们研究了加利福尼亚州南部两个港口的海洋底栖“污垢”群落的发展。通过对固着的表层底栖物种的研究，我们发现，随着群落聚集过程中总物种和外来物种丰富度的增加，外来物种的数量减少，并且在考虑到空间可用性后，这种影响仍然存在。我们还发现，外来物种丰度的变化随着时间的推移而减少。在整个组装期间，当空间充裕而丰富度较低时，外来物种丰度的收益最大。总而言之，我们发现对生物抗性的支持比入侵融化更大，这表明在这些群落的早期发展过程中，本地和外来物种都对生物抗性做出了贡献。然而，我们的结果表明，生物抗性并不总是减少外来物种的最终优势。
High community diversity may either prevent or promote the establishment of exotic species. The biotic resistance hypothesis holds that species-rich communities are more resistant to invasion than species-poor communities due to mechanisms including greater interspecific competition. Conversely, the invasional meltdown hypothesis proposes that greater exotic diversity increases invasibility via facilitative interactions between exotic species. To evaluate the degree to which biotic resistance or invasional meltdown influences marine community structure during the assembly period, we studied the development of marine epibenthic "fouling" communities at two southern California harbors. With a focus on sessile epibenthic species, we found that fewer exotic species established as total and exotic richness increased during community assembly and that this effect remained after accounting for space availability. We also found that changes in exotic abundance decreased over time. Throughout the assembly period, gains in exotic abundance were greatest when space was abundant and richness was low. Altogether, we found greater support for biotic resistance than invasional meltdown, suggesting that both native and exotic species contribute to biotic resistance during early development of these communities. However, our results indicate that biotic resistance may not always reduce the eventual dominance of exotic species.