Collaborative Research: Rates of Long-Term Climate and Vegetation Change in Eastern North America and Europe

对北美东部化石-花粉数据变化率的分析表明，许多遗址在10,000-14,000年前最后一次冰川消融期间和过去1000年期间经历了重大变化。这项拟议研究的主要目标是确定北美东部过去3000年和瑞典过去14,000年来气候和植被变化的时间、规模和地理模式。来自北美东部一系列地点的高频花粉数据将被用来详细分析过去千年中发生的明显快速的变化，并找出气候和后哥伦布时代的人为原因。来自瑞典南部40个晚期冰川遗址的数据将被用来比较斯堪的纳维亚晚期冰川和北美晚期冰川的时间结构。可归因于农业和其他人类活动(而不是气候影响)的植被变化率将通过对比来自人类影响强烈的地区的瑞典遗址和来自受影响较小的边缘地区的地点来评估。这项研究将确定北美东部和欧洲植被快速变化的同步程度，从而确定大气环流发生重大快速变化的可能时间。研究结果还将揭示近期植被在多大程度上是暂时的，以及北美定居前植被在多大程度上有理由成为现代研究的稳定基线。

Analyses of rates of change in fossil-pollen data from eastern North America reveal that many sites experienced major changes 10,000-14,000 years ago during the last deglaciation and again during the last 1000 years. The major objective of the proposed research is to determine the timing, magnitude, and geographic patterns of the changes in climate and vegetation during the past 3000 years in eastern North America and during the past 14,000 years in Sweden. High-frequency pollen data from an array of sites across eastern North America will be used to analyze in detail the apparently rapid changes occurring during the past millennium and to sort out the climatic and post- Columbian anthropogenic causes. Data from 40 late-glacial sites in southern Sweden will be used to compare the temporal structure of the Scandinavian late-glacial with that of North America. Rates of vegetation change attributable to agriculture and other human activities (as opposed to climatic influences) will be evaluated by contrasting Swedish sites from areas having intensive human impact iwth those from marginal areas receiving little impact. This research will establish the degree to which rapid vegetation changes in eastern North America and Europe are synchronous and will thus identify probable times of major rapid changes in atmospheric circulation. The results will also reveal the degree to which recent vegetation is transitory and to which presettlement vegetation in North America justifiably serves as a steady-state baseline for modern studies.