Spatial-Temporal Dynamics of Brant Herbivore Interactions and Ecosystem Processes in Coastal Tundra of the Yukon-Kuskokwim Delta in Western Alaska

Sedinger这个项目是与阿拉斯加大学和科罗拉多州立大学合作的。 它由极地计划办公室，环境生物学和生态学以及生态系统研究部资助。 在接下来的五年里，主要研究人员将解决在阿拉斯加育空-Kuskokwim（Y-K）三角洲沿海苔原的鹅放牧系统中植物食草动物相互作用和相关生态系统过程的时空变化。 他们的基本假设是，草食动物和早期演替状态之间的相互作用是紧密耦合的，因此草食动物需要这些早期演替状态来成功生产后代。 此外，食草动物不仅保持，但能够通过放牧相关活动创造这些早期的演替状态。 此外，植被格局的时空复杂性和食草动物对生境斑块的反应，为演替、生态系统过程和食草动物种群动态带来了相当复杂的问题。（4）草食动物的时空格局在决定生态系统状态中的作用。 这项建议建立在对在Y-K三角洲海岸筑巢的黑雁（Branta bernicla nigricans）的营养和其他因素的人口统计学的16年研究以及对植被/生态系统对食草动物的反应的7年研究的基础上。 这项研究利用了大量的单独标记的布兰特样本，这将为研究小组提供一个前所未有的机会来测量食草动物对其食物质量和数量的人口反应。 深入的食草动物对土壤过程的影响的复杂实验。首席研究员将使用空间生态系统模型（SAVANNA）的修改版本来测试关于食草动物空间格局和生态系统状态之间关系的假设。 SAVANNA将直接与鹅种群模型相关联，以将食草动物动态完全纳入其假设检验中，现场实验旨在使他们能够将SAVANNA参数化用于沿海苔原。 建模还将指导他们的实地实验和跨营养级监测的全面整合。目前的项目还将把对墨西哥同一种群鹅和相关湿地栖息地的研究联系起来。这可能是第一个研究充分整合土壤过程，植被和草食动物在生态系统背景下，在这样一个广泛的空间尺度的动态。

AbstractOPP-99-85831SedingerThis project is collaborative with the University of Alaska and Colorado State University. It is being funded by the Office of Polar Programs, Division of Environmental Biology and Ecology, and Ecosystem Studies. Over the next five years, the Principal Investigators will address spatial-temporal variation in plant herbivore interactions and associated ecosystem processes in a goose grazing system in coastal tundra of the Yukon-Kuskokwim (Y-K) Delta, Alaska. Their fundamental hypothesis is that interactions between herbivores and early successional states are tightly coupled, such that herbivores require these early successional states for successful production of offspring. Furthermore, herbivores not only maintain, but are capable of creating these early successional states by grazing associated activities. Moreover, spatial/temporal complexity in vegetation patterns and the response of herbivores to habitat patches introduce substantial complexity into succession, ecosystem processes and herbivore population dynamics.The Principal Investigators will examine four inter-linked hypotheses: 1) the influence of herbivory on succession; 2) the influence of herbivory on nutrient cycling processes; 3) time lags in the successional response of vegetation to herbivory; and 4) the role that temporal-spatial patterns in herbivory play in determining ecosystem state. This proposal builds on a 16-year study of nutrition and other factors other factors on demography of the black brant (Branta bernicla nigricans) geese that nest on the coast of the Y-K Delta, and on seven years of research on vegetation/ ecosystem response to herbivory. This study takes advantage of a large sample of individually marked brant that will provide the team with an unprecedented opportunity to measure demographic responses of herbivores to the quality and quantity of their food. Intensive herbivory sophisticated experiments on the effects of herbivory on soil processes.The Principal Investigators will use a modified version of a spatial ecosystem model (SAVANNA) to test hypotheses what could not otherwise be examined about the relationship between spatial patterns of herbivory and ecosystem state. SAVANNA will be directly linked to a goose population model to fully incorporate herbivore dynamics into their hypothesis testing, and the field experiments are designed to allow them to parameterize SAVANNA for coastal tundra. Modeling will also serve to guide full integration of their field experiments and monitoring across trophic levels.The current project also will link research on the same population of geese and associated wetland habitats in Mexico. This may be the first study to fully integrate dynamics of soil processes, vegetation and herbivory in an ecosystem context at such a broad spatial scale.