CEE01 The Climate Extremes Experiment (CEE): Assessing ecosystem resistance and resilience to repeated climate extremes at Konza Prairie

Climate extremes, such as drought, are increasing in frequency and intensity, and the ecological consequences of these extreme events can be substantial and widespread. Yet, little is known about the factors that determine recovery (or resilience) of ecosystem function post-drought. Such knowledge is particularly important because post-drought recovery periods can be protracted depending on drought legacy effects (e.g., loss key plant populations, altered community structure and/or biogeochemical processes). These drought legacies may alter ecosystem function for many years post-drought and may impact future sensitivity (both resistance and resilience) to climate extremes. With forecasts of more frequent drought, there is an imperative to understand whether and how post-drought legacies will affect ecosystem response to future drought events. To address this knowledge gap, we experimentally imposed over an eight year period two extreme growing season droughts, each two years in duration followed by a two-year recovery period, in annually burned tallgrass prairie.气候极端事件（如干旱）的发生频率与强度呈持续上升趋势，此类极端事件所引发的生态后果往往影响深远且波及范围广泛。然而，目前学界对于决定干旱后生态系统功能恢复（或恢复力）的关键因素仍知之甚少。此类认知尤为关键，因为干旱后的恢复周期往往会因干旱遗留效应（例如：关键植物种群丧失、群落结构改变以及/或生物地球化学过程扰动）而被拉长。这些干旱遗留效应可能会在干旱结束后的数年乃至更久时间内改变生态系统功能，并影响生态系统未来对气候极端事件的敏感性（包括抵抗力与恢复力）。鉴于未来干旱发生频率将进一步升高的预测，我们亟需探明干旱遗留效应是否以及如何影响生态系统对未来干旱事件的响应。为填补这一认知空白，本研究在每年焚烧的高草草原生态系统中开展了为期八年的控制实验：设置两次极端生长季干旱事件，每次干旱持续两年，随后设置两年的恢复周期。