Linking Ecosystem Processes and Community Structure Along Salinity and Nutrient Gradients In Tropical Marshes

热带沼泽生态系统过程和群落结构沿盐度和营养梯度的联系热带土地利用的加速变化正在增加水生生态系统的营养负荷。这导致物种组成和生态系统功能的变化，如初级生产和养分循环。这项研究的目的是从机理上解释生态系统水平对沿盐度梯度增加的养分输入的反应。Rejmankova博士和他的同事提出，在热带沼泽地，磷(P)和氮(N)的限制之间存在着上下文(盐度)相关的转换。该项目将使用伯利兹磷有限的湿地生态系统作为模型系统，记录如何通过对植物群落个别组成部分的不同限制，沿盐度梯度转移营养限制。一项短期的中层实验将评估单个沼泽成分对不同盐度、P和N水平的响应。一项涉及向一组不同盐度的重复沼泽添加营养物质的长期实验将验证生态系统水平响应的预测。除了更好地了解这些生态系统的学术价值外，该项目还与湿地保护直接相关，并可能提供与伯利兹疟疾控制相关的数据。

Abstract00-889211RejmankovaLinking ecosystem processes and community structure along salinity and nutrient gradients in tropical marshesAccelerated land use change in the tropics is increasing nutrient loading to aquatic ecosystems. This is resulting in changes in species composition and ecosystem functions such as primary production and nutrient cycling. The aim of this research is to obtain a mechanistic explanation for an ecosystem level response to increased nutrient input along a salinity gradient. Dr. Rejmankova and colleagues propose that there is a context (salinity) dependent switch between phosphorus (P) and nitrogen (N) limitation in tropical marshlands. This project will use P-limited wetland ecosystems in Belize as a model system on which to document how nutrient limitation can be shifted along a salinity gradient through different constraints on individual components of plant communities. A short-term mesocosm experiment will evaluate response of individual marsh components to different levels of salinity, P and N. A long-term experiment involving additions of nutrients to a replicated set of marshes of different salinity will verify the predictions of the ecosystem-level response. In addition to the intellectual merit of a better understanding of these ecosystems, the project has immediate relevance to conservation of wetlands, and may provide data that will be relevant to malaria control in Belize.