OPUS: CRS Predicting establishment, competitive interactions, and mortality in desert shrub populations based on spatial structure and intrinsic water-use efficiencies

在过去的四十年里，美国西部莫哈韦沙漠的温度和降水的变化影响了生活在这个沙漠环境中的灌木。气温越来越暖，该地区越来越干燥。在本研究中，将综合39年干旱落叶灌木种群和生理观测数据（约265,000个数据点），以促进我们对干旱和El Niño事件的组合以及灌木生理差异如何影响西部沙漠植物种群结构的理解。这些信息对土地管理者、资源专家和生态学家很重要，因为他们试图更好地管理美国西部广阔的干旱地区，并了解未来气候变化将如何影响这些干旱土地的生态系统。本研究中综合的概念使用了已经收集到的数据，并将植物建立和生存的空间格局与环境变量和不同沙漠灌木物种用水效率的内在差异联系起来。本研究旨在了解植物-植物和植物-环境的相互作用如何构成沙漠植物种群，以及气候变化如何影响这些模式。综合研究的重点是在种群结构受到影响的三个关键生活史阶段进行观察，得出预测结构：种群建立、成年个体之间的竞争以及种群在突然和极端干旱下的下降。如果未来的气候趋势遵循过去39年的干湿模式，或者如果上个世纪的长期干湿循环回归，这种综合还将产生关于人口结构的生态生理方面将如何变化的预测。这种综合将为理解沙漠植物的生理变化如何在种群和种间水平上影响沙漠植物种群结构以及这些模式如何受到已经发生的环境变化的影响提供一个框架。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Over the past four decades, changes in both temperature and precipitation within the Mojave Desert of the western United States have impacted shrubs living in this desert environment. Temperatures are increasingly warmer and the region is getting progressively drier. In this study, 39 years of drought-deciduous shrub population and physiological observations (some 265,000 data points) will be synthesized to advance our understanding of how the combination of drought and El Niño events along with differences in shrub physiologies have shaped plant population structure in western deserts. Such information is important for land managers, resource specialists, and ecologists as they seek to better manage extensive arid regions of the western United States and to understand how future changes in climate will impact these arid land ecosystems. The concepts synthesized in this study use data that has already been collected and will link spatial patterns of plant establishment and survival with environmental variables and intrinsic differences in the efficiency of water use by different desert shrub species. This research aims to understand how plant-plant and plant-environment interactions structure desert plant populations and how changes in climate affect these patterns. The focus of the synthesis is on observations leading to predictive constructs at three key life-history stages when population structure is affected: establishment, competition among adult individuals, and population decline under abrupt and extreme droughts. This synthesis will also generate predictions about how ecophysiological aspects of population structure will change if future climate trends follow the wet-dry pattern of the last 39 years or if the long term wet-dry cycles of the last century return. This synthesis will provide a framework for understanding how variation in plant physiology among desert plants operate at both the population and interspecific levels to affect structure of desert plant populations and how these patterns will be affected by the environmental variability already occurring.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.