RUI: Dynamics of European Buckthorn (Rhamnus cathartica L.) Invasion in the Northeastern United States

外来入侵植物威胁着世界各地自然区域的生态完整性和经济价值。尽管这个日益严重的问题日益严重，但我们对外来植物如何在新的地区扎根并在整个景观中移动的理解是薄弱的。这项研究的目的是描述原产于欧亚大陆的灌木欧洲沙棘在北美新地区的殖民过程，以及这一过程如何随着生态环境的变化而变化。将利用实地观察和实验来检查次生落叶林、针叶林和废弃农田中殖民过程的每个阶段。小气候、土壤和栖息动物的差异将被认为是殖民变化的潜在来源。环境的空间配置也将被视为影响殖民的一个因素。将物种组成、树冠间隙、边缘和溪流与欧洲沙棘分布联系起来的详细的林分水平地图将揭示促进殖民和传播的因素。航空照片和地理信息系统将允许测量该工厂占据的区域的大小、形状和空间背景。这项研究将证明北美森林的碎片化是促进还是抑制欧洲沙棘的传播。欧洲沙棘与当地植物竞争，是燕麦冠锈菌的宿主，燕麦是一种侵袭燕麦作物的疾病。在这种灌木丛中筑巢的本土鸟类捕食率很高，而欧洲沙棘的叶子可能会对本土哺乳动物有毒。这项研究将导致对这种相对未被研究的保护物种的生理学和生态学有更多的了解。此外，这项研究将有助于理解入侵成功是如何受到入侵生态系统特性的影响的。这项研究还将量化木材采伐和农地遗弃造成的森林碎片化如何影响外来物种在景观中的移动。尽管许多入侵物种是在人类改良的环境中发现的，但人们越来越担心原始自然区域中存在入侵物种。了解环境背景在特定环境和景观环境中的影响，将指导土地管理人员和科学家识别对自然环境的潜在威胁。

Invasive non-native plants threaten the ecological integrity and economic value of natural areas throughout the world. Despite the severity of this growing problem, our understanding of how exotic plants become established in new areas and move across the landscape is weak. The objective of this research is to describe the process by which European buckthorn (Rhamnus cathartica), a shrub native to Eurasia, colonizes new areas in North America and how that process varies with ecological context. Field observations and experiments will be used to examine each stage of the colonization process in second-growth deciduous forests, conifer plantations, and abandoned agricultural fields. Differences in microclimate, soils, and resident fauna will be considered as potential sources of variation in colonization. Spatial configuration of the environment also will be considered as a factor affecting colonization. Detailed stand-level maps relating species composition, canopy gaps, edges, and streams to European buckthorn distribution will reveal factors facilitating colonization and spread. Aerial photographs and geographic information systems will allow measurement of size, shape and spatial context of areas occupied by this plant. This research will demonstrate whether fragmentation of North American forests serves to promote or inhibit the spread of European buckthorn.European buckthorn competes with native plants and is a host of oat crown rust fungus, a disease that attacks oat crops. Native birds nesting in this shrub experience high rates of predation, and leaves of European buckthorn may be toxic to native mammals. This research will lead to a greater knowledge of the physiology and ecology of this relatively unstudied species of conservation concern. In addition, this research will contribute to understanding of how invasion success is affected by the properties of invaded ecosystems. This study also will quantify how forest fragmentation due to timber harvest and abandonment of agricultural lands affects the movement of an exotic species across the landscape. Although many invasive species are found in human-modified environments, there is growing concern about the presence of invasive species within pristine natural areas. Understanding the effect of environmental context, within particular settings and among settings in the landscape, will guide land managers and scientists to identify potential threats to natural environments.