Exotic plants with wide ecological niches often invade multiple types of habitats, leading to homogenization of ecosystem structure and functions. How exotic plant invasions affect the structure and functions of benthic food webs in different habitats is poorly understood. We tested how Spartina alterniflora invasions affected benthic food webs in four contrasting types of habitat (Scirpus mariqueter marshes, Phragmites australis marshes, unvegetated tidal creeks, and bare tidal flats) in the Yangtze estuary. We examined distribution pattern of benthic macroinvertebrates, and documented the differences in basal resources of benthic food web by stable isotope analyses of δ¹³C and δ¹⁵N in different habitats. Our results showed that in unvegetated habitats, conversion of tidal creeks and bare tidal flats to exotic marshes following Spartina invasions significantly altered the functional composition of benthic food webs, which was driven partially by bottom‐up processes related to a consumer dietary shift from benthic organic matter to detritus (trophic effect) and by alteration in species composition related to habitat changes (nontrophic effect). In vegetated native habitats, while the replacement of native plants by Spartina consistently led to a shift in consumer diet from benthic organic matter to detritus, it did not significantly alter the functional composition of benthic food webs. These data suggested the relative importance of trophic and nontrophic effects of plant invasions on benthic food webs could vary with habitat structure (e.g., the presence of native vegetation). Our study provides new insights into the mechanisms underlying homogenization of ecosystem structure and functions by exotic plant invasions.

中文翻译：

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外来植物入侵对沿海湿地底栖食物网的栖息地影响

具有广泛生态位的外来植物通常会入侵多种类型的生境，从而导致生态系统结构和功能的均质化。人们对外来植物入侵如何影响不同生境底栖食物网的结构和功能的了解甚少。在长江口，我们测试了互花米草入侵如何影响四种相反类型的生境（Scripus mariqueter沼泽，Phragmites australis沼泽，无植被的潮汐小溪和裸露的滩涂）的底栖食物网。我们研究了大型底栖动物的分布格局，并记录了稳定同位素在底栖食物网的基础资源的差异δ分析¹³ C和δ ¹⁵N在不同的栖息地。我们的研究结果表明，在无植被栖息地，潮沟的转化率和裸滩涂到以下异国沼泽互花米草入侵显著改变底栖食物网的功能组合物，其通过与从底栖有机消费者膳食移自下而上工艺部分地被驱动有害物质（营养作用）和与生境变化有关的物种组成变化（非营养作用）。在植被繁茂的原始栖息地中，而斯巴蒂娜（Spartina）替代了原生植物始终导致消费者饮食从底栖有机物转向碎屑，但并未显着改变底栖食物网的功能组成。这些数据表明，植物入侵对底栖食物网的营养和非营养作用的相对重要性可能随生境结构（例如，天然植被的存在）而变化。我们的研究为外来植物入侵对生态系统结构和功能均质化的潜在机制提供了新的见解。