Beaver, Succession, and Ecosystem Dynamics Across the BorealLandscape

河狸塘的空间格局和性质发生变化 在人口膨胀的过程中突然出现， 池塘建立和废弃的依赖途径。 因此，在本发明中， 河狸池塘的生态系统特性不是随机分布的 也不会随时间随机变化。 该研究项目提出了以下假设： 测定了河狸栖息地的生态系统动态 1）地貌，水文制度，和碳， 建立池塘前的营养库，2） 在高地的食物供应作为海狸饲料，和3）的变化， 在池塘创建过程中的水文状况和营养循环， 遗弃 这些因素中的每一个的相对重要性都在变化， 海狸种群周期，导致多个演替 路径和多个稳定状态。 本计画将在景观与生态系统中验证此假说 尺度：1）分析池塘和邻近的空间格局 河岸森林使用65年的航空照片序列， 地理信息系统、地质统计学和渗流 理论：2）操纵混合物种中的养分有效性 在现场的社区和操纵养分，水， 凋落物在单一栽培的中型生态系统;和3）构建一个规模- 受影响的北方景观动态的依赖模型 Beaver的

The spatial patterns and properties of beaver ponds change abruptly during population expansion, and there are scale- dependent pathways of pond establishment and abandonment. Thus, ecosystem properties of beaver ponds are not randomly distributed across the landscape nor do they change randomly through time. This research project suggests the following hypothesis: Ecosystem dynamics in valleys occupied by beaver are determined by 1) the geomorphology, hydrologic regimes, and carbon and nutrient pools antecedent to pond establishment, 2) changes in food supply in uplands as beaver forage, and 3) changes in the hydrologic regimes and nutrient cycles during pond creation and abandonment. The relative importance of each of theses factors changes during beaver population cycles, resulting in multiple successional pathways and multiple stable states across the landscape. This project will test this hypothesis at landscape and ecosystem scales by: 1) analyses of spatial patterns of ponds and adjacent riparian forests using a 65 year sequence of air photos, geographic information systems, geostatistics, and percolation theory: 2) manipulating nutrient availabilities in mixed species communities in the field and manipulating nutrients, water, and litter in monoculture mesocosms; and 3) constructing a scale- dependent model of the dynamics of boreal landscapes influenced by beaver.