无根藤入侵西沙群岛原生植物群落的机理及生态效应

近年来寄生植物无根藤在我国西沙群岛上的入侵危害日益严重，造成许多珊瑚岛原生植被大面积退化和大量植物死亡。目前尚未发现有关无根藤在西沙珊瑚岛原生群落的入侵机理及生态效应方面的系统性研究。本项目拟以我国西沙热带珊瑚岛受到无根藤入侵原生植物群落为研究对象，并以岛上未受入侵的原生植物群落为对照，开展如下研究：基于无根藤寄主植物的相关功能性状，确定无根藤的寄主类型与寄生偏好；通过凋落物野外分解实验并结合实验期间寄主植物生理性状的变化，探究无根藤入侵过程中植物-土壤的反馈调节作用；结合热带珊瑚岛非生物因素（包括土壤理化性质、鸟粪沉积、距高潮线的距离等）与无根藤入侵，对非生物因子-入侵-原生植被三者进行关联分析，阐明非生物因素-入侵交互作用下无根藤对原生植物群落入侵生态效应的响应机制。研究结果可为热带珊瑚岛原生植被保护、植被修复工具种筛选、无根藤防治等提供科学参考。

The invasion of the parasitic plant Cassytha filiformis has severely damaged native vegetation in the Paracel Islands, resulting in the degradation and death of many native plants. Research on the mechanism and ecological effects of C filiformis invasion on the native community is still an unresolved question in ecology of coral islands. This project intends to select Paracel tropical coral islands’ native communities invaded by C. filiformis as research subject and non-invaded native communities as the control. The following research contents will be carried out: the functional traits of parasitzed host plant to identify the type and preference of C. filiformis parasitism; the litter decomposition experiments are conducted with the changes of host plant characters monitored during the experiment, to explore the plant- soil feedback of C filiformis invasion; the relationship between abiotic factors (including soil phy-chemical properties, guano deposition, distance from the high water line, etc) and C. filiformis are recorded and analyzed to clarify the response mechanism of ecological effects of invasion on plant communities. The research results can provide scientific reference for the protection of native vegetation, selection of tool species for vegetation restoration and prevention of C. filiformis invasion in the Paracel Islands.