REU: Animal Influences on the Aquatic Landscape: Vegetative Patterns, Successional Transitions, and Nutrient Dynamics

该提案涉及水文影响 河狸对演替的营养格局的改变 过渡，以及营养物质在水生物中的分布 北方森林景观的一部分。 研究方向是 围绕三个相关的预测（1）的物理结构 景观决定池塘的建立和位置，湿地 形状和季节动态，但生物反馈（海狸- 食物，有机物-氧化还原电位）决定池塘废弃 和景观的长期动态。 (2)变异性 跃迁概率由 不同时期的水文状况和食物供应 鳞片 在不同的过程中产生不同的滞后时间 多重演替途径和多重平衡。 （三） 由此产生的营养途径是对海狸种群的反应 动力学，滞后时间的系统，地形，和历史的 受影响的地区。 结果表现为植物性 从独特的营养组合的演替模式 特征、水文和初始植被。 假设将通过量化海狸来检验- 在294平方公里的Kabetogama半岛上的景观相互作用， 明尼苏达州北方，来自14个日期的航拍照片 从1927年到1991年（65岁）。 将进行实地研究， 食物供应、水文、氧化还原电位和养分 空房的 试验性的地块养分操作将 用于测量植物群落对水文变化的响应 条件 这些结果将与以下信息相结合： 海狸种群动态研究景观斑块动态 使用嵌套的非平稳马尔可夫模型。 的结果 这项研究将对生态系统产生直接影响， 理解空间和时间转换的动力学 在不同的尺度上，一个基石食草动物的作用， 影响景观斑块和边界动态， 多演替途径，景观营养经济， 生态系统中的滞后反应。

This proposal addresses the effect of hydrologic modifications by beaver on vegetative patterns, successional transitions, and the distribution of nutrients on the aquatic portion of the boreal forest landscape. The research is oriented around three related predictions (1) The physical structure of the landscape determines pond establishment and location, wetland shape and seasonal dynamics, but biological feedbacks (beaver- food, organic matter-redox potential) determine pond abandonment and long-term dynamics of the landscape. (2) Variability in transition probabilities is determined by variations in the hydrologic regime and the food supply over different temporal scales. Different lag times in various processes produce multisuccessional pathways and multiple equilibria. (3) Resultant nutrient pathways are a response to beaver population dynamics, lag-time in the system, topography, and history of the affected areas. The result is manifested by vegetative succession patterns from unique combinations of nutrient characteristics, hydrology, and initial vegetation. The hypotheses will be tested by quantifying beaver- landscape interactions on the 294 km2 Kabetogama Peninsula in northern Minnesota from aerial photographs taken on 14 dates from 1927 to 1991 (65 yrs). Field studies will be conducted of the food supply, hydrology, redox potential, and nutrient availability. Experimental nutrient manipulations of plots will be used to guage plant community response to changing hydrologic conditions. These results will be coupled with information on beaver population dynamics to examine landscape patch dynamics using nested, non-stationary Markovian models. The results of this research will have direct ecosystem implications for understanding the dynamics of spatial and temporal transitions over various scales, the role of a keystone herbivore in influencing landscape patch and boundary dynamics, multisuccessional pathways, landscape nutrient economies, and lag-time responses within ecosystems.