Species richness and interacting factors control invasibility of a marine community

Anthropogenic vectors have moved marine species around the world leading to increased invasions and expanded species' ranges. The biotic resistance hypothesis of Elton (in The ecology of invasions by animals and plants, 1958) predicts that more diverse communities should have greater resistance to invasions, but experiments have been equivocal. We hypothesized that species richness interacts with other factors to determine experimental outcomes. We manipulated species richness, species composition (native and introduced) and availability of bare space in invertebrate assemblages in a marina in Monterey, CA. Increased species richness significantly interacted with both initial cover of native species and of all organisms to collectively decrease recruitment. Although native species decreased recruitment, introduced species had a similar effect, and we concluded that biotic resistance is conferred by total species richness. We suggest that contradictory conclusions in previous studies abo...人为传播媒介（anthropogenic vectors）在全球范围内转运海洋物种，导致外来生物入侵事件频发、物种分布范围不断扩张。埃尔顿（Elton）于1958年在《动植物入侵生态学（The ecology of invasions by animals and plants）》中提出的生物抵抗假说（biotic resistance hypothesis）预测，物种丰富度更高的群落对外来入侵的抵抗力更强，但相关实验结果始终莫衷一是。本研究假设物种丰富度与其他因素存在交互作用，共同决定实验结局。我们在美国加利福尼亚州蒙特雷市的一处游艇码头（marina）的无脊椎动物群落中，对物种丰富度、物种组成（本地物种与外来物种）以及空白空间可获取性开展了人为操控实验。结果显示，物种丰富度的提升与本地物种初始盖度及所有生物的初始盖度均存在显著交互效应，共同降低了种群补充（recruitment）量。尽管本地物种能够抑制种群补充，但外来物种也表现出了相似的作用效果，因此我们得出结论：生物抵抗性由群落总物种丰富度所赋予。我们认为，此前多项研究得出的矛盾结论源于……