The spread of invasive species is a major component of global ecological change and how and when to manage particular species is a difficult empirical question. Ideally, these decisions should be based on the specific impacts of invading species including both their effects on native competitors and how they may or may not play similar roles in broader ecosystem functioning. Halophila stipulacea is an invasive seagrass currently spreading through the Caribbean, and as seagrasses are foundation species, the effects of invasion have the potential to be particularly far-reaching. To evaluate the impacts of H. stipulacea we quantified spread and potential for displacement of native seagrasses as well as the effects of invasion on multiple ecosystem processes, particularly resource support for higher trophic levels and habitat creation. Long-term monitoring suggested that H. stipulacea likely displaces some native seagrasses (Syringodium filiforme and Halodule wrightii), but not others. Halophila stipulacea had lower N and protein levels and higher C:N ratios than native seagrasses, and as such is a poorer quality resource for consumers. We also observed significantly lower consumption of H. stipulacea than the native S. filiforme but limited differences compared to Thalassia testudinum. We found H. stipulacea created a more nutrient limited environment than T. testudinum and there were significantly distinct invertebrate assemblages in native- and invasive-dominated seagrass beds, but no difference in species richness or invertebrate biomass. These results suggest that the spread of H. stipulacea would impact a variety of ecological processes, potentially restructuring seagrass ecosystems through both direct impacts on environmental conditions (e.g., nutrient availability) and indirect food web interactions.

中文翻译：

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小巨人：快速入侵的海草改变了相对于本地基础物种的生态系统功能

入侵物种的传播是全球生态变化的主要组成部分，如何以及何时管理特定物种是一个困难的实证问题。理想情况下，这些决定应基于入侵物种的具体影响，包括它们对本地竞争者的影响以及它们如何在更广泛的生态系统功能中发挥或不发挥类似作用。Halophila stipulacea 是一种目前在加勒比地区蔓延的入侵海草，由于海草是基础物种，入侵的影响有可能特别深远。为了评估 H. stipulacea 的影响，我们量化了原生海草迁移的传播和潜力，以及入侵对多个生态系统过程的影响，特别是对更高营养水平和栖息地创造的资源支持。长期监测表明 H. stipulacea 可能会取代一些本地海草（Syringodium filiforme 和 Halodule wrightii），但不会取代其他海草。与天然海草相比，Halophila stipulacea 具有较低的 N 和蛋白质水平以及较高的 C:N 比，因此对消费者来说是一种质量较差的资源。我们还观察到 H. stipulacea 的消耗量明显低于原生 S. filiforme，但与 Thalassia testudinum 相比差异有限。我们发现 H. stipulacea 创造了比 T. testudinum 更受营养限制的环境，并且在原生和入侵占主导地位的海草床中存在明显不同的无脊椎动物组合，但在物种丰富度或无脊椎动物生物量方面没有差异。这些结果表明 H. stipulacea 的传播会影响各种生态过程，