Using restoration to test community assembly in a heavily invaded ecosystem

生态恢复是帮助恢复生态系统的过程，是减轻人类造成的自然系统退化影响的重要工具。例如，旱地恢复被用于防治荒漠化，溪流恢复可以改善鲑鱼等鱼类的栖息地。然而，尽管修复项目很重要，但它可能很难取得成功，而且结果往往是不可预测的。鉴于这些挑战，我的研究计划试图将生态学理论与恢复实践联系起来，以提高恢复的可预测性和成功。在接下来的五年里，我将使用群落集合和基于特征的生态学理论来揭示生态对干扰、入侵和恢复的反应机制。社区组装框架关注的是环境如何过滤掉不太适应当地条件的物种。特别强大的过滤器将根据植物特性的子集进行选择，例如干燥条件下过滤掉低效利用水分的物种。这可能会导致群落内的趋同，所有物种都有一组相似的特征，对最强的过滤器做出反应。我将通过大小规模的野外实验和观测研究相结合的方式来评估干扰在草本植物群落中作为过滤器的作用。具体地说，我的研究重点是不列颠哥伦比亚省的加里橡树草地。基于从低强度鹿压力到高强度鹿压力的梯度，我将跟踪放牧加剧时群落特征的趋同。干扰也与非本土物种入侵速度的增加有关，尽管这通常被理解为到达和殖民，而不是外来物种固有的特征。然而，外来物种可能代表了一组基于它们与人类的关系的强烈偏见的生殖和生长特征，可能在种子投入中表现得更好，并可能逃避放牧等干扰。因此，外来物种对放牧的反应可能与本地物种不同，如果忽略起源，可能会以不可预测的方式驱动群落在前、中和后的干扰。因此，我的工作将同时考虑社区集会中的干扰和入侵，既是退化社区组成的驱动因素，也是恢复行动下恢复的预测因素。我将分别和一起评估放牧对本地和外来物种特征的影响，并通过跟踪鹿的饮食偏好、草地上的种子投入和外来物种特征的偏见来分析为什么外来物种可能会做出不同的反应。最后，我将测试管理放牧、清除外来物种或实施这两种策略对土著社区恢复结果的影响。我的工作将为加拿大最优先的保护区之一的管理层提供信息，并将加强对干扰和入侵如何改变社区聚集模式的生态理解。

Ecological restoration, the process of assisting the recovery of an ecosystem, is an essential tool for mitigating the effects of human-induced degradation in natural systems. For example, restoration in drylands has been used to fight desertification, and stream restoration can enhance habitat for fish such as salmon. Despite its importance, however, success in restoration projects can be difficult to achieve, and outcomes are often unpredictable. In light of these challenges, my research program seeks to link ecological theory and restoration practice to enhance the predictability and success of restoration. Over the next five years, I will use theories of community assembly and trait-based ecology to uncover mechanisms of ecological responses to disturbance, invasion, and restoration. Community assembly frameworks focus on how the environment acts to filter out species that are not well adapted to local conditions. Particularly strong filters will select for a subset of plant traits, such as dry conditions filtering out species that use water inefficiently. This can cause convergence within a community, with all species having a similar set of traits in response to the strongest filter. I will assess the role of disturbance as a filter in herbaceous communities through a combination of large- and small-scale field experiments and observational studies. Specifically, my research focuses on Garry oak meadows in British Columbia. Based on a gradient of low intensity deer pressure to high intensity, I will track community trait convergence as grazing intensifies. Disturbance is also linked to increased rates of invasion by non-native species, though this is generally understood in terms of arrival and colonization rather than traits intrinsic to exotic species. However, exotic species may represent a strongly biased set of reproductive and growth traits based on their relationship to humans, may be better represented in seed inputs, and may escape disturbances like grazing. Thus, exotic species' response to grazing may be distinct from natives, and may drive community assembly pre-, during, and post-disturbance in unpredictable ways if origin is ignored. As a result, my work will simultaneously consider disturbance and invasion in community assembly, both as drivers of composition in degraded communities and as predictors of recovery under restoration actions. I will assess grazing impacts on traits in native and exotic species separately and together, and will pull apart why exotic species may respond differently by tracking deer diet preferences, seed inputs in meadows, and bias in exotic species traits. Finally, I will test how managing grazing, removing exotics, or implementing both strategies influence restoration outcomes in native communities. My work will inform management in one of the highest priority conservation areas of Canada, and will enhance ecological understanding of how disturbance and invasion alter community assembly patterns.