湿地外来克隆植物大米草种群扩张和自然衰退的水文驱动机制

Biological invasion of exotic plants is important ecological issue. For extotic clonal plant, Spartina anglica is invading most the Atlantic coast in the word, however it is undergoing dieback in coast China. Because the hydrological condition is one of important enviromental factors which influce plant growth, reproduction and spread in salt masrh, however it is not very clear hydrological mechanism for Spartina anglica invasion and dieback in different sites. We will compare the growth and reproduction traits difference among three diffenent geography Spartina anglica popupulation from American, Chinese and English coast under the same and heterogeneity water condition. Three sites respectively delegate invasion, dieback and native Spartina anglica population. Following, we will analyse the plasticity and competition difference among three population under different hydrological condition change. In order to study the hydrological driving mechanism of S.anglica population invasion and dieback, we mainly do some experiments with the methods of greenhouse controlling experiments, molecular marker and isotope tracer basing on experiment and analysis ecology theory. We will test these scientific hypothesises that " the invasion S. anglica population from American coast have strong adapatability and competition than those of dieback and native population". These results will provide some materials for plant population ecology and plant invasion ecoloy, which will offer some new approches for controlling some other extic invasive plants.

外来植物入侵是重要的生态学问题，对于外来克隆植物大米草在大西洋沿岸进行扩张的同时，在中国海岸带却出现自然衰退，原因不明。水文是决定滨海湿地植物生长繁殖及扩张的重要环境因子之一，但目前对水文条件如何影响大米草种群在不同区域进行扩张和自然衰退的机制缺乏深入研究。本项目以入侵地美国海岸带种群，衰退地中国海岸带种群和原产地英国海岸带种群为研究对象，以实验生态学、比较生态学理论为基础，综合运用温室控制实验、分子标记及同位素示踪等方法，研究不同地理位置大米草种群生长繁殖性状的差异，以及在不同水文变异条件下适应性和竞争力的差异，检验科学假说"湿地外来克隆植物大米草扩张种群适应水文条件变异的能力及此条件下的竞争力优于衰退地种群和原产地种群"，进而研究外来克隆植物大米草在不同区域进行入侵和自然衰退的水文驱动机制。该研究成果将为丰富植物种群生态学提供素材，也将对深入理解植物入侵及其入侵控制提供理论依据。

按照计划书已经完成了有关不同水文条件下外来克隆植物大米草适应性和竞争力的影响，并依此为基础进行了扩充，探讨了水文条件对其它克隆植物及群落生长及适应性的影响，进而对湿地生态系统生态功能的影响。本项目主要基于野外指标测量和取样，结合野外和温室控制实验，研究了水文条件对外来克隆植物大米草的入侵及衰退机制研究，主要从水文导致的基质类型差异，不同水位梯度对克隆植物大米草与本土种种间关系的影响，研究发现不同水位梯度下及由水文导致的基质差异影响了外来克隆植物大米草与本土种的种间关系，形成了不平衡的种间关系格局，从而探讨了影响外来克隆植物大米草入侵及衰退的主要水文因子。以此为切入点，研究了不同水位梯度、水位波动、水体养分、同质水文条件对克隆植物个体及群落的生产力及群落的结构的影响，并深入探讨了克隆整合对其克隆植物适应不同水文条件性的贡献，以及对湿地生态系统功能作用发挥的影响。