Collaborative Research: Effects of Nutrient Stress on a Co-evolved Food Web

生态学家面临的一个主要挑战是了解环境应激源对群落结构和功能的影响。这项研究将确定一种新的压力源--大气中氮沉积的增加--如何改变与北部猪笼草相关的碎屑食物链的动态。提出了三种不同类型的分析，以解决与水罐计划群落营养动态相关的假说。野外“脉冲”实验将操纵食物链的物种组成和氮源。氮同位素将被用来揭示人类来源和猎物来源的氮的移动。温室“压榨”实验将测量不同食物网状结构对猪笼草养分吸收和生长的影响。实验结果将被用来开发群落聚集和食物网动态的模型。这项拟议的研究将揭示人为应激源对共同进化系统的重要性，并有助于更深入地理解自上而下和自下而上的力对非平衡组合动力学的对比影响。这项研究将产生通用模型，可应用于其他经历新压力源的生态社区。它将让研究生和本科生参与监督和独立的研究。

A major challenge for ecologists is to understand the effects that environmental stressors have on community structure and function. This research will determine how a novel stressor - increased atmospheric deposition of nitrogen - is altering the dynamics of the detritus-based food web associated with the northern pitcher plant, Sarracenia purpurea. Three different types of analyses are proposed to address hypotheses related to the trophic dynamics of pitcher plan communities. A field 'pulse' experiment will manipulate the species composition of the food web and the source of nitrogen. Nitrogen isotopes will be used to reveal the movement of nitrogen derived from anthropogenic sources and from prey. A greenhouse 'press' experiment will measure the effects of different food web structures on nutrient uptake and growth of pitcher plants. Experimental results will be used to develop models of community assembly and of food web dynamics. The proposed research will reveal the importance of anthropogenic stressors on co-evolved systems and contribute to a deeper understanding of the contrasting effects of top-down and bottom-up forces on the dynamics of non-equilibrial assemblages. The research will result in general models that can be applied to other ecological communities experiencing novel stressors. It will involve graduate and undergraduate students in supervised and independent research.