Linking Dispersal and Population Dynamics of White-footed Mice to Tree Seed Predation in Patchy Landscapes

9807115 Richard S.Ostfeld，Charles D.Canham，Felicia Kees...这项研究将把到目前为止一直被视为概念上不同现象的两个关键生态过程联系起来：在斑驳的景观中移动动物的扩散动态，以及种子消费者对森林景观中树木更新的影响。主要目标是(1)确定白足小鼠(Permyscus Leucopus)的种群是否在美国东北部斑驳的后农业景观中表现出源-汇动态，以及(2)揭示老鼠的传播模式(无论是源-汇模式还是替代模式)对树木种子的生存和最终森林再生的影响。这将允许将动物的扩散动态与植物群落的动态联系起来。将研究三种景观斑块类型：以橡树为主的森林、以枫树为主的森林和以灌木和草本植物为主的老城区。所有三种补丁类型都沿着广泛而尖锐的边缘相互连接，而老鼠占据了所有三种补丁类型。假设橡树斑块在橡子丰收后的年份支持源种群，在此期间枫树斑块和老田斑块是汇，PI将：(1)测量斑块类型之间的净扩散方向；(2)使用直接测量的死亡率和出生率来估计每种斑块类型的种群内的平均适合度；以及(3)封闭种群并跟踪斑块类型(Oldfield)的生长轨迹。总而言之，这些方法将把源-汇动态与替代模型区分开来。

9807115Richard S. Ostfeld, Charles D. Canham, Felicia KeesingThis research will link two key ecological processes that until now have been treated as conceptually distinct phenomena: dispersal dynamics of mobile animals in a patchy landscape, and the effects of seed consumers on tree regeneration in forested landscapes. The primary goals are to (1) determine whether populations of white-footed mice (Peromyscus leucopus) demonstrate source-sink dynamics in the patchy, postagricultural landscapes of northeastern U.S. and (2) reveal the consequences of dispersal patterns by mice (whether source-sink or an alternative model) for the survival of tree seeds and ultimately for forest regeneration. This will allow for linkage of animal dispersal dynamics with community dynamics of plants. Three landscape patch types will be studied: oak-dominated forests, maple-dominated forests, and shrub- and herb-dominated oldfields. All three patch types are connected to one another along extensive, sharp edges, and mice occupy all three patch types. It is hypothesized that oak patches support source populations in post-acorn-mast years, during which maple and oldfield patches are sinks and the PIs will: (1) measure the net direction of dispersal between patch types; (2) estimate the mean fitness within populations in each patch type, using direct measurements of mortality and natality; and (3) enclose populations and follow growth trajectories in the patch type (oldfield). Together, these approaches will distinguish source-sink dynamics from alternative models.