DISSERTATION RESEARCH: Diversity and invasion within a predator community: impacts on herbivore suppression

人类活动通过破坏栖息地和入侵物种的扩散导致生物多样性的广泛下降。食肉动物尤其容易受到种群变化甚至灭绝的影响。由此产生的捕食者物种组成的变化可能反过来减少或增加食草动物的种群密度，这取决于捕食者是否协同行动以减少食草动物，或者它们是否相互竞争和/或相互吃掉。捕食者的捕猎策略可能是决定它们如何相互作用的重要因素。在实验室和野外实验中，研究人员将利用不同蜘蛛物种（包括入侵蜘蛛Cheiracanthium mildei）的组合，比较具有相似和不同捕猎策略的捕食者物种之间相互作用的结果。此外，本研究将评估入侵捕食者在物种管理贫乏的生态系统中取得的惊人成功是否由于缺乏生态上相似的本地捕食者物种。本研究解决了两个重要的保护问题：1)生物多样性和2)入侵物种。通过评估捕食者多样性对食物网的影响，有可能确定对保护重要生态系统功能至关重要的物种或物种组合。本研究还将考察自然生态系统在缓解入侵物种在附近管理生态系统中的传播方面的价值。研究结果将对直接研究区域（加州纳帕县和索诺玛县）的保护工作产生直接影响，但可能对生态学家如何看待生物多样性与入侵之间的关系产生广泛影响。

Human activities are causing widespread declines in biodiversity through both habitat destruction and the spread of invasive species. Predators are particularly vulnerable to population changes and even extinction. The resulting changes in predator species composition may, in turn, decrease or increase herbivore population densities, depending on whether predators act synergistically to reduce herbivores, or whether they compete with and/or eat each other. Hunting strategies of predators may be important in determining how they interact. In laboratory and field experiments different combinations of spider species, including the invasive spider Cheiracanthium mildei, will be manipulated to compare outcomes of interactions between predator species with similar and different hunting strategies. In addition, this research will assess whether the often spectacular success of invasive predators in species-poor managed ecosystems is due to the absence of ecologically similar native predator species. This study addresses two issues that are important in conservation: 1) biodiversity and 2) invasive species. By assessing the impact of predator diversity in the food web, it may be possible to identify species, or assemblages of species, that are important for preserving important ecosystem functions. This study will also examine the value of natural ecosystems in mitigating the spread of invasive species in nearby managed ecosystems. Results will have a direct impact on conservation efforts in the immediate area of study (Napa and Sonoma Counties, CA), but could have wide-reaching implications on how ecologists view the relationship between biodiversity and invasion.