SGER: The Effect of Preexisting Differences in Invasive Plant Abundance on he Impacts of Hurricane Rita on East Texas bottomland hardwood forests

干扰被广泛认为是促进入侵（“干扰假说”），也许是暂时增加资源供应相对于吸收的原生植被。然而，这一理论的主要内容仍然未经检验。此外，越来越多的证据表明，殖民化在确定当地多样性和物种组成方面发挥着重要作用（“补充限制假说”），但没有在森林中进行过实验测试。总之，这两个假设表明，一个重要的相互作用之间发生的“窗口的机会”的干扰，生存的干扰，和种子或幼苗的可用性，以利用暂时丰富的资源的植被的特点。2005年9月，飓风丽塔的风眼经过德克萨斯州东部，对大灌木丛国家保护区的一项长期实验造成了广泛的破坏。实验包括16个40英亩的地块，其中成熟的入侵乌桕树已被从一半的地块中移除。由于这些移除，这些地块在多个生命阶段的乌桕树密度不同。这是一个机会，以检查一个大的干扰不同的优势入侵植物物种的预先存在的密度，由于随机实验设计的地块上的效果。PI将于2005年秋季和2006年春季在这些受干扰的地点建立和监测采样区。将对高分辨率图像进行分析，以确定更大尺度的扰动。更广泛的影响：这项工作将带来新的知识，以迅速变化的领域日益增加的社会重要性。它将为本科生的科学生涯做好准备，培养研究生，并促进直接在该领域和通过传播我们的数据和结果与资源管理人员的合作。它将为未来入侵物种的预测提供实用信息，并有助于指导当前问题物种的管理。

Disturbance is widely believed to facilitate invasions ("Disturbance Hypothesis") perhaps by temporarily increasing the supply of resources relative to uptake by native vegetation. However, the main elements of this theory remain untested. In addition, there is growing evidence that colonization plays an important role in determining local diversity and species composition ("Recruitment Limitation Hypothesis") but no experimental tests have been performed in forests. Together, these two hypotheses suggest that an important interplay occurs among "windows of opportunity" created by disturbance, the characteristics of the vegetation that survive the disturbance, and the availability of seeds or seedlings to take advantage of temporarily abundant resources. In September 2005, the eye of Hurricane Rita passed through eastern Texas causing extensive damage to a long-term experiment in the Big Thicket National Preserve. The experiment consists of 16 forty acre plots in which the mature invasive Chinese Tallow Trees have been removed from half of the plots. Because of these removals, the plots differ in the density of Tallow Trees in multiple life stages. This is an opportunity to examine the effect of a large disturbance on plots that differ in the preexisting density of a dominant invasive plant species due to random experimental design. The PI will set up and monitor sampling areas within these disturbed sites in fall 2005 and in spring 2006. High resolution imagery will be analyzed to determine disturbance at larger scales. Broader Impacts: This work will bring new knowledge to a rapidly changing field of increasing societal importance. It will prepare undergraduate students for science careers, train graduate students, and facilitate collaborations with resource managers both directly in the field and through the dissemination of our data and results. It will provide practical information for the prediction of future invasive species and help guide the management of current problem species.