Edge dynamics in the cold-temperate deciduous forest of eastern Canada

边缘往往以不同于任何一种相邻生态系统的典型速率的过程为特征：较高的速率--过度活力；较低的速率--缺乏活力。边缘可分为三种类型：开阔的边缘是最近形成的边缘，沿其森林结构尚未发生变化；边缘随着时间的推移而关闭，因为与边缘接壤的树木产生更密集的树冠，而灌木下层产生更密集的树叶；嵌入的边缘随着时间的推移而发展，因为灌木和乔木物种被逐渐扩展到邻近的旧田地的更远的距离。由于边缘的性质不同，边缘之间的加工速度差异可能或多或少明显。在这项建议中，我想确定边缘类型如何影响森林和非森林植物物种的人口统计过程。我的一般假设是，边缘对人口过程的影响取决于边缘的性质：我认为开放边缘是那些人口过程速率差异最显著的边缘，随着边缘变得封闭或随着时间的推移，差异逐渐减小。作者还提出，在不同的林下功能类群中，春季开花的短暂物种受边缘类型的影响较小，主要环境变量沿边缘的空间差异在春季比夏季更温和。由于边缘的环境异质性通常大于相邻生态系统的“内部”，边缘是测试与环境异质性有关的多样性-生产关系的理想系统。由于开放边缘、封闭边缘和嵌入边缘的特征不同，因此可以使用不同类型的边缘来检验环境异质性对多样性-生产关系的重要性。我认为，开放边缘是那些环境异质性较高的边缘，对多样性-生产关系的影响较大。这项研究具有重要的保护意义，因为边缘附近的种群动态变化可能会导致高度碎片化的景观中更大的灭绝风险。

Edges are often characterized by processes with rates that differ from those typical of either type of adjacent ecosystems: higher rates - hyperdynamism; lower rates - hypodynamism. Three types of edge can be identified: an open edge is a recently-formed edge along which no change in forest structure has yet occurred; an edge closes with time as trees bordering the edge produce a denser canopy and as the shrub understory produces a denser foliage; an embedded edge develops with time as shrub and tree species are recruited at progressively greater distances into the adjacent old-field. Because edges differ in their nature, differences in process rates across edges may be more or less apparent. In this proposal, I want to determine how edge type affects the demographic processes of both forest and non-forest plant species. My general hypothesis is that edge effects on population processes depend on the nature of the edge: I suggest that open edges are those where differences in the rates of demographic processes are most significant, differences decreasing as edges become closed or embedded with time. I also propose that, among the different understory functional groups, spring-flowering ephemeral species are those that are less affected by edge type, spatial contrasts along edges in major environmental variables being more moderate in spring than in summer. Because environmental heterogeneity is typically greater across edges than in the 'interior' of either adjacent ecosystem, edges represent ideal systems to test the diversity-production relationship with regard to environmental heterogeneity. As open, closed and embedded edges differ in their characteristics, the significance of environmental heterogeneity for the diversity-production relationship can be tested using different types of edge. I suggest that open edges are those across which environmental heterogeneity is higher, with greater effects on the diversity-production relationship. This research has significant conservation implications as altered population dynamics near edges may lead to greater risks of extinction in highly fragmented landscapes.