The Effects of Large Mammal Browsing on the Dynamics of Northern Ecosystems

这一建议解决驼鹿与植物种群动态的相互作用，它们与碳和氮循环的反馈，以及随后北方景观的变化。主要的假设是驼鹿促进了北方森林植被的斑块化。这种斑块性是由于物种组成在整个景观中选择性的、非随机的觅食模式的变化造成的；物种对浏览的不同反应；褐斑植物的差异建立以及由植被变化引起的营养循环的变化。该项目将量化密歇根州皇家岛国家公园几个山谷中驼鹿在土壤、喂食站、栖息地和景观尺度上的相互作用。这些山谷具有不同的扰动机制和不同的植物种类组合。野外研究将确定觅食的空间对应关系、食物和覆盖物的分布、浏览质量、植物种子和凋落物的扩散、植物的建立和土壤氮的有效性。这些数据将汇集在一个地理信息系统中，该系统将与森林模拟模型相结合。计算机研究将解决觅食策略如何导致不同植被和土壤空间格局的发展，以及栖息地的空间变异性如何影响驼鹿种群动态。调查人员完全有资格做这类研究，大学的设施也绰绰有余。

This proposal addresses the interactions of moose with the dynamics of plant populations, their feedbacks with carbon and nitrogen cycles, and subsequent changes in boreal landscapes. The main hypothesis is that moose promote patchiness of vegetation in boreal forests. This patchiness results from alternation of species composition by selective, non-random foraging patterns across the landscape; different responses of species to browsing; differential establishment of plants in browsed patches; and changes in nutrient cycles caused by these changes in vegetation. The project will quantify moose interactions at soil, feeding station, habitat, and landscape scales in several valleys on Isle Royale National Park, Michigan. These valleys have different disturbance regimes and different assemblages of plant species. Field studies will determine spatial correspondences of foraging, the distribution of food and cover, browse quality, plant seed and litter dispersal, plant establishment, and soil nitrogen availability. These data will be assembled in a geographic information system that will be coupled with a forest simulation model. Computer studies will address how foraging strategies cause development of different spatial patterns of vegetation and soils, and how spatial variability in habitat influences moose population dynamics. The Investigators are well qualified to do the type of research and the University facilities are more than adequate.