互花米草入侵长江口盐沼不同植物群落对底栖食物网的影响及其机制

营养作用和非营养作用被认为是入侵植物对食物网影响的两种重要途径，是近年来入侵生物学领域的一个研究热点。诸多研究表明外来植物在不同入侵地导致食物网出现不同的响应，在此过程中，两种作用途径对食物网变化的贡献差异尚不清楚；而这对解释外来植物入侵对生态系统后果的产生机制非常重要。本项目拟以外来植物互花米草入侵长江口盐沼为切入点，应用稳定同位素、脂肪酸和胃含物分析方法，研究其在入侵海三棱藨草、芦苇、糙叶苔草以及微藻类植物群落后对底栖食物网的影响，定量分析生物群落结构、食源组成、取食关系变化。同时通过环境理化因子的分析研究非营养作用对食物网变化的驱动作用，通过稳定同位素标记示踪研究营养作用对食物网的驱动过程，从而探讨植物入侵对食物网的影响作用机制，为阐明外来植物影响生态系统结构和功能的过程及机制提供重要案例和科学依据，并可望在入侵生物学领域取得原创性成果。

Trophic and non-trophic effect were important pathway which affect food web by plant invasion, and has become a hot debate in the research field of invasion biology. Many studies showed food web have different response to exotic plant invasion in different habitats. The different effects and relative contribution of the two effect pathway on food web changes are still unclear. This project plan to study the effect and mechanism of the invasive Spartina alterniflora on benthic food web in different native plant communities at the Yangtze River estuarine marshes. By stable isotope, fatty acid and stomach contents analyses, quantitative analyze the change of benthic community structure, food resource composition and feeding relationship by plant invasion. At the same time, environmental factors analysis used to explore the food web changes by non-trophic effect, and stable isotope tracer control experiment used to analyze the driving process of trophic effects on food web. This study will also reveal the different mechanism of food web changes when compare different native plant community with invaded community, and provide important cases for explaining the underlying mechanisms of invasive plant affect ecosystem structure and functions.