EAGER: Collaborative Research: Environmental Variability at Dryland Ecotones

干旱和半干旱生态系统覆盖了地球陆地表面的40%以上，并在全球范围内不断扩大。预计这些生态系统将经历与年平均气温升高和降水变异性增加相关的变化。然而，科学目前既缺乏数据，也缺乏理解，无法将平均温度和降水变化在空间、时间和从个体生物到整个生态系统的生物组织水平上的后果联系起来。2015年，控制大尺度天气模式的振荡之一——太平洋年代际振荡——从凉爽/干燥阶段转变为温暖/潮湿阶段。这种转变表明，在接下来的20年里，美国西南部的年降水量将会增加。在预期的向湿润期过渡期间的生态响应将提供重要的机会，以增加对降水变化对旱地生态的影响的科学认识，包括物种特征、物种多样性和相互作用以及生态系统过程。通过统一这些不同的子领域，研究人员将对跨尺度的生态响应与环境变化之间的联系机制获得新的见解。这项EAGER提案将支持各级学习的教育和推广活动，覆盖美洲原住民和西班牙裔社区。研究小组将与土地管理人员保持联系，他们可以利用这项研究的数据作出管理决策。EAGER研究将包括收集气象学、植物物种生物量、蚱蜢、小型哺乳动物和蜜蜂物种的连续数据。研究小组将把现有的和新收集的数据整合到一个性状数据库中，继续进行涉及基础植物物种移除的实验，并开展涉及火灾、生物结壳干扰和慢性氮沉积的生物群系特异性实验。这些数据将用于陆地生态系统模型（TECO）和过渡带模型（WAVE）的正演建模，以及消费者随机动态程序，其中模型将作为数据分析和集成的工具，以及探索实验中未表示的参数空间的工具。这个复杂的项目将观测和实验数据与模型结合起来，为旱地生态产生新的预测是有风险的，然而，拟议的活动应该通过发展和测试关于气候变化的生态后果的新理论来推进生态学的前沿。

Arid and semi-arid ecosystems cover more-than 40% of the land surface on Earth and are expanding in their global extent. These ecosystems are expected to experience changes associated with increases in average annual temperatures and increases in the variability of precipitation. However, science currently lacks both the data and understanding to link consequences of average temperatures and precipitation variance over space, time, and levels of biological organization from individual organisms to whole ecosystems. In 2015, one of the oscillations that control large-scale weather patterns, the Pacific Decadal Oscillation, switched from a cool / dry phase to a warm / wet phase. That switch suggests that during the next 2 decades the American southwest will experience an increase in annual precipitation. Ecological responses during the anticipated transition to a wetter period will provide important opportunities to increase scientific understanding of the impacts of variation in precipitation on dryland ecology, including species traits, species diversity and interactions, and ecosystem processes. By unifying these diverse subfields the researchers will be poised to obtain new insights into the mechanisms that link ecological response to environmental variance across scales. This EAGER proposal will support education and outreach activities at all levels of learning, reaching Native American and Hispanic communities. The research team will maintain ties with land managers that can use the data from this research in making management decisions. The EAGER research will include the collection of continuous data on meteorology, plant species biomass, and counts of grasshopper, small mammal, and bee species. The research team will assemble existing and newly collected data into a Trait Database, continue experiments involving removals of foundation plant species, and carry out biome-specific experiments involving fires, biocrust disturbance, and chronic nitrogen deposition. The data will be used in forward modeling with the Terrestrial Ecosystem Model (TECO) and an Ecotone Model (WAVE) as well as a Consumer Stochastic Dynamic Program where the models will function as tools for data analysis and integration as well as tools to explore parameter space not represented in the experiments. This complex project that combines observational and experimental data with models to generate novel forecasts for dryland ecology is risky, however, the proposed activities should advance the frontiers of ecology by developing and testing new theory on the ecological consequences of climate variance.