无瓣海桑引种对人工湿地水生动物多样性的影响

The exotic mangrove plant of Sonneratia apetala is very important for mangroves restoration in mud flat. It has been widely cultivated in coastal areas of Southern China. Our former work found that the biomass and species diversity of aquatic animal in wetlands of artificial mangroves of Sonneratia apetala were significantly lower than those in indigenous mangroves. In order to find the reasons that causes the lower biomass and species diversity of aquatic animal in wetlands of artificial mangroves of Sonneratia apetala, we will take the Sonneratia apetala as research object and carry out the following work to explore the influence mechanism of Sonneratia apetala introduction on the aquatic animals in artificial wetlands:(1) The aquatic animals will be put into the artificial mangroves of Sonneratia apetala and indigenous mangroves of the same forest age and restoration background. The biomass and population establishment situation of aquatic animals in different mangroves wetlands will be compared.(2)The food source, soil physical and chemical properties, forest canopy closure and the enrichment ability of pollutants of these artificial mangroves will be studied to explore the influence mechanism of Sonneratia apetala on aquatic economic animals in wetlands of artificial mangroves.(3)Permanent sample plots will be established for a long-term observation to verify and supplement the influence mechanism. The study results would provide a paradigm of exotic species’s influence on indigenous biological resources and ecological security, and provide the basis for Sonneratia apetala scientific introduction and mangrove afforestation. What is the more,the work would provide theoretical guidance and practical basis to improve the economic value of the Sonneratia apetala artificial wetlands.

外来红树植物无瓣海桑对滩涂红树林恢复具有重要的意义，目前已在我国华南沿海地区广泛种植。前期研究发现无瓣海桑人工林湿地水生动物多样性和生物量明显低于乡土红树植物人工林。为深入研究其原因，本项目拟以无瓣海桑为研究对象，开展如下工作揭示无瓣海桑引种对湿地水生动物的影响机制：（1）通过人工林湿地水生动物人工投放实验，比较分析各种生活型水生动物在无瓣海桑和乡土红树植物人工林湿地中种群建立情况和生物量的差异；（2）从食物源、土壤理化性质、林内郁闭度、对污染物富集能力等方面探索无瓣海桑对林下湿地水生动物的影响机制；（3）建立永久样地进行长期观测，对影响机制进行验证、修正和补充。研究结果为揭示外来物种对本地生物资源和生态安全的影响提供范例，为无瓣海桑科学引种和滩涂红树林造林提供决策依据，也为提高人工湿地的经济价值奠定理论指导和实践基础。

外来红树植物无瓣海桑对于滩涂红树林恢复具有重要的意义，目前在我国华南沿海地区广泛种植。本项目在前期基础上，深入研究无瓣海桑人工林湿地水生动物物种多样性减少和生物量低下的原因，具体地：（1）通过水生动物人工投放实验，发现无瓣海桑人工林湿地中各种生活型水生动物种群建立情况和生物量均差于林龄相同的乡土红树植物人工林湿地。穴居型(甲壳纲蟹类)和游泳底栖型（甲壳纲几种虾类和硬骨鱼纲鱼类）在无瓣海桑人工林湿地中种群建立情况和生物量优于底上附着型（软体动物腹足纲）和底内型（双壳纲、多毛类）。但仍低于相同林龄的乡土红树植物秋茄、木榄和桐花树人工林。（2）影响无瓣海桑人工林水生动物生长的主要原因有：由于无瓣海桑的速生性，土壤的快速酸性化明显不利于底内型动物的生长；无瓣海桑凋落物的脂肪酸含量不同于乡土红树植物，本地一些底栖动物对这种食物源“不适应”或“不喜欢”；无瓣海桑的速生性使人工林郁闭度迅速升高，郁闭度过高会影响林下大型海藻、底栖微藻的光合作用，这对于以大型海藻、底栖微藻为食的动物会有不利影响；无瓣海桑过密的植物根丛也使底内生活的动物钻沙或挖洞受到影响；无瓣海桑对重金属和多环芳烃的吸附能力强于乡土红树植物，使得底泥的污染物积累浓度较高，也影响了底内生活动物的生长。（3）通过对无瓣海桑纯林改造，即在林下混交木榄幼苗，增加林地乡土红树植物凋落物食物源，可增加林地水生动物的多样性。（4）建立了永久样地，对影响机制进行验证、修正和补充。本研究结果可为无瓣海桑科学引种和林地水生经济动物增殖提供理论依据。