Ecosystem- and community-level effects of biological invasion

入侵物种是当前环境问题的前沿。生物入侵者可以通过改变竞争、植物生长和腐烂等基本生态系统过程来破坏生态系统。为了管理入侵，我们必须首先了解入侵的后果，并将这些后果与控制活动的环境成本进行权衡。了解入侵物种如何影响生态系统和群落，也为我们了解群落是如何聚集的，以及是什么决定了生态系统抵抗或从干扰中恢复的能力。这些基本的生态问题是我研究项目的重点。* *作为一个模型系统，我建议研究非本地芦苇（芦苇）入侵淡水沼泽的生态系统效应。我们对淡水中这种侵略性入侵者的影响的认识严重过时和不足。为了更好地了解芦苇入侵如何影响：i)湿地结构；Ii)湿地生态系统过程（如植物生长和分解）；(3)候鸟和濒危鸟类对湿地的利用。我提出了一个创新的实地研究项目，主要包括两个部分。* * 1。入侵与未入侵湿地样地基本生态系统过程比较。比较芦苇入侵样地与香蒲草甸和沼泽草甸样地的植物生长、腐烂和碳储量。研究计划的这一部分将包括凋落物移植实验和直接土壤特征，以梳理入侵和未入侵地块之间的生长和腐烂差异是由于凋落物组成的差异还是由于环境条件的变化。* * 2。入侵前、新入侵和已入侵时期鸟类丰度和群落组成的比较。之前有限的研究表明，在入侵的早期阶段，对鸟类群落组成的影响可能很小，而芦苇实际上可以增加鸟类的丰度。然而，一旦入侵已经确立，普通芦苇的任何积极影响都不太可能持续下去。* *在我的探索计划的第一阶段，研究将在安大略省的长点进行。长点湿地占伊利湖北岸所有湿地栖息地的70%，是大陆重要的候鸟集散地。已建立的芦苇林的密集、难以穿透的单一栽培特征可能危及该湿地和其他湿地的濒危物种（例如，最小卤鸟），迫切需要进一步的研究，以便为管理决策和确定恢复重点提供信息。这项研究的结果也将有助于解决有关入侵生态学和湿地弹性的更大问题。此外，我提议的项目将促进滑铁卢大学、加拿大鸟类研究中心、长点国家野生动物区和长点研究与教育中心之间的伙伴关系和知识转移。这将导致培养高技能人才：下一代环境科学家和保护生物学家，他们将解决未来的生态危机。

Invasive species are at the forefront of current environmental issues. Biological invaders can disrupt ecosystems by altering fundamental ecosystem processes like competition, plant growth and decay. To manage invasions, we must first understand the consequences of invasion and weigh these against the environmental costs of control activities. Understanding how invasive species influence ecosystems and communities also provides us with insight into how communities assemble, and what determines the capacity of ecosystems to resist or recover from disturbance. These fundamental ecological issues are the focus of my research program.* *As a model system, I propose to examine the ecosystem effects of invasion by non-native Phragmites australis (Common Reed) in freshwater marshes. Our knowledge of the effects of this aggressive invader in freshwater is woefully out-dated and inadequate. To better understand how Common Reed invasion affects: i) wetland structure; ii) wetland ecosystem processes (e.g., plant growth and decomposition); and, iii) use of wetlands by migratory and imperiled birds, I am proposing an innovative field-based research program with two major components.* *1. A comparison of basic ecosystem processes between invaded and uninvaded wetland plots. Plant growth, decay, and carbon storage will be compared between plots invaded by Common Reed and plots in cattail and marsh meadow communities. This component of the research program will include a litter transplant experiment and direct soil characterizations to tease apart whether differences in growth and decay between invaded and uninvaded plots are due to differences in litter composition or due to variability in environmental conditions.* *2. A comparison of bird abundance and community composition between time periods that represent pre-invasion, new invasion, and established invasion. Limited previous work has shown that in the early stages of invasion effects on the bird community composition can be minor, and that bird abundance can actually be enhanced by Common Reed. However, it is unlikely that any positive effect of Common Reed will persist once the invasion has become established.* *For this first phase of my Discovery program, research will be conducted at Long Point, Ontario. The Long Point wetlands constitute 70% of all wetland habitat on the north shore of Lake Erie, and are a migratory bird staging area of continental importance. The dense, impenetrable monocultures characteristic of established Common Reed stands could imperil species at risk (e.g., Least Bittern) in this and other wetlands, and further study is urgently needed to inform management decisions and set restoration priorities. Results of this research will also contribute to addressing larger questions about invasion ecology and the resiliency of wetlands. Additionally, my proposed program will foster partnerships and knowledge transfer between the University of Waterloo, Bird Studies Canada, the Long Point National Wildlife Area, and the Long Point Research and Education Centre. This will lead to the training of highly skilled personnel: the next generation of environmental scientists and conservation biologists who will tackle ecological crises of the future.