NSFDEB-NERC: Warming's silver lining? Thermal compensation at multiple levels of organization may promote ecosystem stability in response to drought

我们拟议研究的目标是了解河流生态系统的长期变暖如何影响它们的反应（即，抵抗力和复原力）对日益普遍和严重的水文干旱的影响。人类活动产生的人为温室气体排放导致全球气温上升，极端气候事件的频率和强度增加。虽然已知这些驱动因素的变化会分别影响流动沃茨的结构和功能，但很少有研究调查它们的组合或相互作用。普遍的观点是，气候变暖和干旱联合收割机将产生比任何一种压力单独造成的更极端的生态后果。然而，新出现的证据表明，变暖可能会引发“补偿”反应-适应性和生态-这可能会减轻极端干旱的影响。我们的合作NSFDEB-NERC项目将结合联合收割机实验室测量（冰岛大学），温度和干旱的流围隔操纵（英国伯明翰大学），和全范围干旱操纵（Hengill地热集水区，冰岛），以测试的总体假设，长期变暖增强流生态系统的稳定性（电阻和弹性），以应对干旱事件。我们的第一个目标是集中在个人层面上，调查是否生理适应变暖的影响无脊椎动物的碳利用效率和干旱的弹性和恢复的作用。我们的第二个目标是量化整个无脊椎动物群落的抵抗力和恢复力及其生物量生产，以应对自然和实验温度梯度的干旱。我们的最终目标将探讨潜在的生态系统层面的补偿反应，通过研究如何变暖引起的变化，营养供应和初级生产者影响稳定的生态系统代谢和氮吸收，以应对干旱。

The goal of our proposed research is to understand how long-term warming of stream ecosystems influences their response (i.e., resistance and resilience) to increasing prevalence and intensity of hydrologic drought. Anthropogenic greenhouse gas emissions from human activities are generating both a rise in global temperatures and an increase in the frequency and intensity of extreme climatic events. While shifts in these drivers are known to affect the structure and function of running waters separately, few studies have investigated their combined or interactive effects. The prevailing view is that warming and drought will combine to produce more extreme ecological consequences than would result from either stressor alone. Yet, emerging evidence suggests that warming may trigger 'compensatory' responses - both adaptive and ecological - that may have the potential to lessen the impacts of extreme drought. Our collaborative NSFDEB-NERC project will combine laboratory measurements (University of Iceland), stream mesocosm manipulations of temperature and drought (University of Birmingham, U.K.), and whole-reach drought manipulations (Hengill geothermal catchment, Iceland) to test the overarching hypothesis that long-warming enhances stream ecosystem stability (both resistance and resilience) in response to drought events. Our first objective is focused at the individual level, investigating whether physiological adaptations to warming influence invertebrate carbon use efficiencies and their role in drought resilience and recovery. Our second objective seeks to quantify resistance and resilience of entire invertebrate communities and their biomass production in response to drought across natural and experimental thermal gradients. Our final objective will explore the potential for ecosystem-level compensatory responses by examining how warming-induced shifts in nutrient supply and primary producers influence stability of ecosystem metabolism and nitrogen uptake in response to drought.