Collaborative proposal: Latitudinal variation in top-down and bottom-up control of salt marsh herbivores

说明. 对生物多样性和物种相互作用的纬度模式的兴趣已有数百年的历史。 对个体相互作用的纬度变化的研究表明，植物防御、食草和捕食在低纬度都更强烈。 然而，由于这些过程相互作用且在空间上相关，因此了解生物多样性和食物网结构的纬度模式将需要比迄今为止更复杂的实验方法。 大西洋海岸盐沼是研究不同纬度的多种营养过程之间相互作用的理想系统。 三个主要的食物网因素的变化在盐沼植物系统在整个纬度平行：植物质量，栖息地结构，和顶级捕食者的存在。 PI将通过实验研究这些因素的空间变化如何导致对食草动物丰度和食物网结构的不同控制。意义 生态学家对地理格局有着长期的兴趣，但这个项目将是第一个实验性地研究纬度梯度上自上而下和自下而上力量的空间变化的项目。研究结果将增加我们对食物网结构、杂食动物、相互作用的空间变化和一般盐沼生态的理解。 该项目将利用现有的研究储备网络（NERR，LTER）培训一名博士后，两名研究生和两名本科生，并包括与K-12教育工作者的联系。

Description. Interest in latitudinal patterns of biodiversity and species interactions is centuries old. Studies of latitudinal variation in individual interactions suggest that plant defenses, herbivory and predation are all more intense at lower latitudes. However, because these processes interact and are spatially correlated, understanding latitudinal patterns of biodiversity and food-web structure will require a more sophisticated experimental approach than exists to date. Atlantic coastal salt marshes are ideal systems for examining interactions between multiple trophic processes that vary across latitude. Three major food-web factors change in parallel in salt marsh plant systems across latitude: plant quality, habitat structure, and the presence of top predators. The PIs will experimentally examine how spatial variation in these factors leads to different controls on herbivore abundance and food web structure across latitude. Significance. Ecologists have a long-standing interest in geographic patterns, but this project will be the first to experimentally investigate spatial variation in top-down and bottom-up forces across a latitudinal gradient. The results will increase our understanding of food-web structure, omnivory, spatial variation in interactions, and general salt marsh ecology. The project will use utilize existing networks of research reserves (NERR, LTER) train a postdoc, two graduate students and two undergraduates, and include outreach to K-12 educators.