Climate Extremes and Episodic Invasions: a Late Holocene Case Study From the Western Great Lakes Region

该项目探讨了百年到千年尺度的气候变化，特别是极端潮湿和干燥，在管理的克里思，速度和入侵和扩张的三个经济和生态上重要的树种（黄桦，铁杉，山毛榉）的空间模式的作用西北范围限制在西部五大湖地区。 在过去的5000年里，这些物种的地理范围和种群规模已经扩大，初步证据表明，这些扩张是由气候变化引起的。 我们将使用古生态学方法（分析湖泊和泥炭地沉积物中的花粉、宏体化石和气孔）来描绘这些扩张的时空模式，并使用古气候学方法（分析泥炭地沉积物中的古生物学和地球化学指标）来详细、独立地记录气候变化的时空模式。 古生态学和古气候学数据的比较将在一系列时间尺度上将生态响应与气候变化联系起来。 了解过去的生态和气候动力学将有助于我们预测对当前和未来气候变化的生态反应的能力。

This project explores the role of centennial to millennial-scale climate variability, particularly wet and dry extremes, in governing the tempo, rate, and spatial pattern of invasion and expansion of three economically and ecologically important tree species (yellow birch, hemlock, beech) near their northwestern range limits in the western Great Lakes region. Geographic ranges and population sizes of these species have expanded episodically in the last 5000 years, and preliminary evidence indicates that these expansions were paced by climate variability. We will use paleoecological methods (analysis of pollen, macrofossils, and stomates from lake and peatland sediments) to delineate the spatial and temporal patterns of these expansions, and paleoclimatological methods (analyses of paleontological and geochemical indicators from peatland sediments) to develop detailed, independent records of spatial and temporal patterns of climate variability. Comparison of the paleoecological and paleoclimatological data will link the ecological responses to climate variations across a range of timescales. Understanding ecological and climatic dynamics of the past will contribute to our ability to predict ecological responses to ongoing and future climatic change.