Collaborative Research: Drought as a trigger for rapid state shifts in kettlehole ecosystems

该项目将利用壶穴生态系统的沉积物记录来研究对长期或极端干旱事件的生态反应。这些生态系统广泛存在于以前的冰川景观中。沿着威斯康星州北部的景观梯度，将使用古生态技术来研究干旱、泥炭地的建立和扩张以及湖泊生态系统动态之间的关系。研究将检验以下假设：1)泥炭地的发育是突然发生的，而不是逐渐发生的，由干旱变化引发；2)盆地形态和景观位置决定泥炭地是否发育；3)泥炭地的快速发展导致残留湖泊的突然变化，导致水壶系统内碳储存速率的变化。与全球气候变化相关的变暖温度预计将导致许多中纬度地区更加频繁和强烈的干旱。这些预测对生态学家和资源管理者提出了挑战；然而，令人震惊的是，几乎没有数据集为理解生态系统对这些预期变化的反应提供基础。这项研究将对水气候变化在引发生态系统突然和永久状态变化中的作用提供关键的、长期的观点。这种阈值响应很难预测或预测，这项研究将为评估生态系统的相对敏感性和脆弱性提供基础。

This project will use the sediment record of kettlehole ecosystems to study ecological responses to prolonged or extreme drought events. These ecosystems are widespread in previously glaciated landscapes. Relationships among drought, peatland establishment and expansion, and lake-ecosystem dynamics will be examined using paleoecological techniques along a landscape gradient in northern Wisconsin. Research will test the hypotheses that 1) peatland development occurs suddenly rather than gradually, triggered by drought variability, 2) basin morphology and landscape position determine whether peatlands develop, and 3) the rapid development of peatland leads to abrupt changes in remnant lakes, producing changes in rates of carbon storage within kettle systems.Warming temperatures associated with global climate change are expected to lead to more frequent and intense droughts in many mid-latitude regions. These predictions present a challenge to ecologists and resource managers; yet alarmingly few datasets exist to provide a basis for understanding ecosystem responses to these anticipated changes. This research will provide critical, long-term perspectives on the role of hydroclimate variability in triggering abrupt and permanent state shifts in ecosystems. Such threshold responses are difficult to anticipate or predict, and the research will provide a foundation for evaluating the relative sensitivity and vulnerability of ecological systems.