Impacts of Spatially Heterogeneous Nitrogen to Grazer Distribution and Activity: Effects on Ecosystem Function in Tallgrass Prairie

在世界各地的草原上，食草动物在整个景观中遇到高度可变的食物质量，以应对最近放牧活动和火灾之间的相互作用。 本研究项目探讨（a）植物氮和牧草质量的空间变异如何决定北美草原系统中食草动物的分布;（B）放牧活动是否以及如何通过改变生境、养分循环和动植物生物多样性来调节各种其他草原生态系统过程。 该项目的总体假设是，饲料（蛋白质）和物理结构的栖息地火放牧相互作用的氮含量决定景观使用的野牛，从而增加栖息地的异质性。这反过来又影响到其他重要的食草动物，从而影响到生态系统的功能和生物多样性。 研究将在堪萨斯东部Konza Prairie生物站的高草草原进行，方法是跟踪野牛放牧模式与绘制的饲料质量的关系，将使用新的遥感技术进行测量。野牛的运动活动将使用GPS（全球定位系统）项圈跟踪，以提供精确的野牛位置，每小时全年。 这些数据将被映射到饲料氮浓度分布在精细和粗空间尺度上使用GIS（地理信息系统）技术。 将通过比较现场响应与使用现场过去的研究活动和新发现开发的预定预测，评估植物群落和优势食草昆虫（蚱蜢）对野牛放牧活动引起的栖息地变化的响应。此外，栖息地结构和牧草质量的作用，野牛喂养活动和蝗虫的多样性和丰富性将进行评估与两个大的现场实验，独立操作氮肥和植被高度。 最终，本研究将评估野牛放牧和火灾干扰对栖息地异质性的创造和维持，评估其在草原生态系统功能中的作用，并有助于了解全球放牧系统。拟议研究的结果将立即实际应用于北美和地球仪普遍存在的具有重要经济意义的放牧系统。并为保护全球本土食草动物及其栖息地提供基本的科学依据。 该项目的成果将被开发成正式的基于网络的教育模块，传播给多个不同的受众，包括学校系统，广大公众，推广计划和保护组织。将为土地管理人员编制和赞助讲习班和网上材料，以解释遥感、地理信息系统和其他技术在管理和保护放牧系统方面的前景，并提供这些生态系统的生态组成部分的迫切需要的摘要。该项目还将有助于研究生和本科生的研究培训，并为中学科学教师提供急需的研究机会;将特别鼓励来自科学领域代表性不足的群体的学生和教师参加。 一名来自堪萨斯学校系统的高中生物教师被招募参加该项目，该学校系统的低收入家庭和高度移动的军人家庭比例很高。

In grasslands worldwide, grazers encounter highly variable food quality across the landscape in response to recent interactions between grazing activity and fire. This research project examines (a) how such spatial variability in plant nitrogen and forage quality determines the distribution of herbivore grazers in a North American grassland system; and (b) if and how grazing activity then regulates a variety of other grassland ecosystem processes by altering habitats, nutrient cycling and the biodiversity of plants and animals. The overarching hypothesis of this project is that nitrogen content in forage (protein) and physical structure of the habitat resulting from fire-grazing interactions determines landscape use by bison, thereby increasing habitat heterogeneity. This, in turn, affects other important herbivores and thus impacts ecosystem function and biodiversity. Research will be performed in a tallgrass prairie at Konza Prairie Biological Station in eastern Kansas by following patterns of bison grazing in relation to mapped forage quality, which will be measured using new remote sensing technology. Bison movement activity will be tracked using GPS (global positioning system) collars to provide precise bison locations every hour throughout the year. These data will then be mapped on to the distribution of forage nitrogen concentrations at fine and coarse spatial scales using GIS (geographic information system) technology. Responses by plant communities and dominant insect herbivores (grasshoppers) to habitat changes from bison grazing activity will be assessed by comparing field responses to predetermined predictions that were developed using past research activities at the site and new discoveries. In addition, the roles of habitat structure and forage quality to both bison feeding activity and the diversity and abundance of grasshoppers will be evaluated with two large field experiments that independently manipulate N-fertilization and vegetation height. Ultimately, this study will evaluate the creation and maintenance of habitat heterogeneity from disturbance by bison grazing and fire, assess its role in ecosystem functioning of grasslands, and contribute to the understanding of grazing systems worldwide.Results of proposed research will have immediate, practical application to economically important grazing systems commonly found throughout North America and across the globe, and provide basic scientific foundations for conserving native grazers and their habitats worldwide. Results of this project will be developed into formal web-based educational modules to be disseminated to multiple, diverse audiences, including school systems, the public at large, extension programs and conservation organizations. Workshops and web-based materials for land managers will be developed and sponsored to explain the promise of remote sensing, GIS and other technologies that could be helpful in managing and conserving grazing systems as well as provide critically needed summaries of the ecological components of these ecosystems. The project will also contribute to research training for graduate and undergraduate students as well as provide much needed exposure to research by secondary science teachers; students and teachers from groups underrepresented in science will be especially encouraged to participate. A high school biology teacher from a Kansas school system with a high proportion of low income families and highly mobile military families has been recruited to the project.