Dissertation Research: Effects of Plant Diversity on Community Invasibility in a California Riparian System

[90198d ' antonio]对入侵物种影响的极大关注激发了人们对多样性群落更好地抵御入侵的假设的新兴趣。在自然群落中评估这一假设已被证明具有挑战性，因为多样性的变化受干扰、资源、消费者等因素的控制，因此与干扰、资源、消费者等因素共变——这些因素直接影响入侵。本研究将分离出多样性的独立影响和这些共变因素对黄鳝河中占主导地位的莎草丛入侵性的影响。每个丛丛都有一个小型社区，自然变化的本地植物多样性，使其成为探索多样性-入侵关系的理想系统。外来植物和本地植物将被引入到自然多样性变化的象牙上，并被引入到通过实验操纵多样性的象牙上。这种强大的结合将使这些研究人员能够确定种群数量如何影响其入侵性，评估这种关系由本地多样性驱动的程度，并探索潜在的机制。通过进一步研究多样性与不可侵犯性在比种群范围更广的尺度上的关系，本研究还将评估多样性与不可侵犯性的关系如何随尺度变化。这项研究将有助于保护受威胁的河岸群落，并提高景观入侵模式的可预测性。

9901984D'AntonioGreat concern over the impacts of invasive species has stimulated renewed interest in the hypothesis that diverse communities better resist invasion. Evaluating this hypothesis in natural communities has proven challenging because variation in diversity is controlled by, and therefore covaries with, disturbance, resources, consumers, etc.-the same factors directly impacting invasions. This research will isolate the independent effects of diversity and the effects of these covarying factors on the invasibility of sedge tussocks that dominate the Eel River. Each tussock houses a mini-community, varying naturally in native plant diversity, making an ideal system to explore the diversity-invasibility relationship. Exotic and native plants will be introduced on tussocks varying naturally in diversity and onto tussocks where diversity has been experimentally manipulated. This powerful combination will enable these investigators to determine how the number of species on a tussock influences its invasibility, evaluate the degree to which this relationship is driven by native diversity, and explore the underlying mechanisms. By additionally examining how diversity relates to invasibility at scales broader than the tussock, this research will also evaluate how the diversity-invasibility relationship changes with scale. This research will aid the conservation of threatened riparian communities, and enhance the predictability of invasion patterns across landscapes.