Rapid vegetation shifts in the Uinta Mountains (Utah and Wyoming, USA) during the Late Pleistocene and Holocene
Rapid vegetation shifts in the Uinta Mountains (Utah and Wyoming, USA) during the Late Pleistocene and Holocene
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DOI：
10.1016/j.palaeo.2015.08.026
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发表时间：
2015-11
期刊：
影响因子：
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通讯作者：
Lisbeth A. Louderback;David Rhode;D. Madsen;Michael Metcalf
中科院分区：
文献类型：
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作者：
Lisbeth A. Louderback;David Rhode;D. Madsen;Michael Metcalf
Uinta山脉位于主要气候制度之间的重要过渡地带，因此对重大气候变化和随之而来的植被变化很敏感。从犹他州和怀俄明州交界处的Uinta山地(分别是沼泽湖沼泽和沼泽营地)采集了两个花粉芯，用来分析从最新更新世到全新世的植被变化。这些记录与落基山脉相邻部分的记录相一致，都表明在大约11,700-11,200千卡的BP期间，从高山草原到开阔的云杉公园发生了重大转变。第二次向小松林的重大转移始于约8400大卡年前的沼泽湖沼泽，可能是优势物种对气候变暖的直接反应和/或敏感交错带附近树种竞争等级微妙变化的结果。由于冷空气排放和地貌位置等一系列复杂的局部因素，导致了小学生林发展速度和充分表现的差异(在沼泽营地花费了近2000年的时间)。在整个全新世晚期，小叶松林一直持续存在，似乎是长期的地区性“顶峰”森林，而不是宁静的栖息地。火灾似乎并没有引发该地区全新世中期从云杉为主的森林向以杉木为主的森林的转变，但可能是火灾长期存在到今天的原因。
The Uinta Mountains lie along an important transition between major climate regimes and thus are sensitive to major climatic changes and consequent vegetation shifts. Two pollen cores from montane Uinta sites on the Utah–Wyoming border (Marsh Lake Bog and Camp Bog, respectively) were used to analyze vegetation shifts from the latest Pleistocene through the Holocene. The records correspond with those from adjacent portions of the Rocky Mountains, all demonstrating a major shift from alpine steppe to open spruce parkland at ~ 11,700–11,200 cal yr BP. A second major shift to lodgepole pine forest began at ~ 8400 cal yr BP at Marsh Lake Bog and could have been a direct response of the dominant species to warmer conditions and/or the result of subtle changes in the competitive hierarchy of tree species near a sensitive ecotone. The difference in the rate and full expression of lodgepole forest development (taking nearly 2000 years longer at Camp Bog) was probably due to a set of complex and local factors, such as cold air drainage and landscape position. Lodgepole pine forest persisted throughout the late Holocene and appears to be the long-term regional “climax” forest, rather than a seral habitat. Fire does not appear to have triggered the middle Holocene shift from spruce-dominated to lodgepole pine-dominated forests in this area but may have contributed to its long-term persistence to the present day.