Plant community assembly and disassembly with climate change

气候对生态群落的组成有多大影响？如果气候是构建群落的主要力量，那么气候变暖应该可以预见地导致当地群落中适应寒冷的物种的损失，而不是适应温暖的物种。或者，如果区域气候没有强烈地构建当地社区，那么物种组成可能不会随着气候变化而发生太大变化。然而，经历气候变暖的当地社区物种组成明显缺乏变化也可能是由于物种改变其地理范围的能力有限，例如，扩散速度慢。不幸的是，这两种可能性有着非常不同的含义;第一种可能性表明社区可能对气候变化有一定的适应能力，而后者意味着社区的敏感性，特别是在气候变化加速的情况下。这项研究将测试社区恢复力与对最近和未来气候变化的敏感性的重要性，通过检查在两个太平洋西北国家公园跨区域气候梯度收集的植物物种组成的独特历史数据集。 该项目将有助于我们了解气候变化的后果，并将此信息传达给国家公园服务和太平洋西北部的其他资源管理人员。 该项目还将为学生提供研究和培训机会，以加强科学工作者队伍，尽管区分具有类似预期结果的驱动因素存在固有挑战，但该项目将在预测植物群落在气候变化明显停滞的情况下的变化问题上取得进展。具体来说，该项目将确定气候对太平洋西北部山区植物群落的影响有多强。 将使用30多年前在两个国家公园（北喀斯喀特国家公园和雷尼尔山国家公园）收集的植物群落组成的再调查数据集来检验关于群落组成和生物气候变量之间关系的假设。 这一历史数据将与新开发的联合物种分布模型和影响小气候的景观特征的高分辨率数据相结合。 研究目的是：I.评估宏观和微观气候变量对群落组成的重要性; II.研究过去四十年来的群落变化，以确定最近气候变化的成分周转是否与气候缓冲（弹性）与滞后物种反应（敏感性）相一致; III.在大尺度和小尺度气候梯度上进行多物种种子添加实验，以分析补充限制和人口惯性（导致时滞敏感性的因素）以及宏观或微观气候缓冲（促进对气候变化的适应性的因素）在社区组装早期阶段的作用。

How strongly does climate influence the composition of ecological communities? If climate is the predominant force structuring communities, climate warming should predictably result in the loss of cold-adapted species at the expense of warm-adapted species in local communities. Alternatively, if regional climate doesn't strongly structure local communities, then species composition may not change much with climate change. However, an apparent lack of change in the species composition of local communities experiencing climate warming can also arise from a limited ability of species to shift their geographic ranges, e.g., slow rate of dispersal. Unfortunately, these two possibilities have very different implications; the first suggests communities may be somewhat resilient to climate change, while the latter implies community sensitivity, especially as climate change accelerates. This research will test the importance of community resilience vs. sensitivity to recent and future climate change, by examining unique historic data sets of plant species composition collected across regional climatic gradients in two Pacific Northwest National Parks. The project will contribute to our understanding of the consequences of climate change and communicate this information to National Park Service and other resource managers in the Pacific Northwest. This project will also provide opportunities for student research and training that will strengthen the scientific workforce.This project will make progress on the problem of predicting change in plant communities with climate change given apparent stasis, despite the inherent challenges of differentiating drivers with similar expected outcomes. Specifically, this project will determine how strongly climate influences plant communities in the mountains of the Pacific Northwest. Hypotheses on relations of community composition and bioclimatic variables will be tested using resurvey data sets of plant community composition originally collected over 30 years ago in two National Parks (North Cascades National Park and Mount Rainier National Park). This historic data will be combined with newly developed joint species distribution models and high resolution data on the landscape features that influence microclimate. Research objectives are to: I. Assess the importance of macro and microclimatic variables for community composition; II. Examine community shifts over the last four decades to determine whether compositional turnover with recent climate change is consistent with climatic buffering (resilience) vs. lagged species responses (sensitivity); and III. Conduct a multi-species seed addition experiment across large-scale and fine-scale climatic gradients to parse out the roles of recruitment limitation and demographic inertia (factors that contributed to time-lagged sensitivity) and macro- or microclimatic buffering (factors that promote resilience to climate change) in the early stages of community assembly.