Biodiverse ecosystems are sometimes inherently resistant to invasion, but environmental change can facilitate invasion by disturbing natural communities and providing resources that are underutilised by native species. In such cases, sufficiently abundant native predators may help to limit invasive population growth. We studied native and invasive seastars feeding under two mussel aquaculture sites in south-east Australia, to determine whether food-rich farm habitats are likely to be reproductive hotspots for the invasive seastar (Asterias amurensis) and whether the larger native seastar (Coscinasterias muricata) reduces the value of the farms for the invader. We found that invaders were not significantly more abundant inside the farms, despite individuals residing within the farms having higher body condition metrics and reproductive investment than those outside. By contrast, the native seastar was 25 × more abundant inside the two farms than outside. We observed several intraguild predation events and an absence of small invaders at the farms despite reports of high larval recruitment to these environments, consistent with some level of biotic control by the native predator. A laboratory choice experiment showed that invaders were strongly attracted to mussels except when the native predator was present. Together, these findings indicate that a combination of predation and predator evasion may play a role in reducing the value of food-rich anthropogenic habitats for this invasive species.

生物多样性生态系统有时固有地具有抵御入侵的能力，但环境变化可以通过干扰自然群落并提供未被本地物种充分利用的资源来促进入侵。在这种情况下，足够丰富的本地捕食者可能有助于限制入侵种群的增长。我们研究了在澳大利亚东南部两个贻贝养殖场下觅食的原生海星和入侵海星，以确定食物丰富的农场栖息地是否可能成为入侵海星（Asterias amurensis）的繁殖热点，以及较大的本土海星（Coscinasterias muricata））降低了入侵者农场的价值。我们发现，尽管居住在农场内的人的身体状况指标和生殖投资要比外面的人高，但农场内的入侵者并没有明显更多。相比之下，两个农场内部的本地海星比外部农场多25倍。尽管有报道称这些环境中有大量幼虫，这与当地捕食者对生物的控制水平保持一致，但我们还是观察到了几次公会内捕食事件，以及农场中没有小入侵者。实验室选择实验表明，除存在天然捕食者外，入侵者被贻贝强烈吸引。一起，