Postglacial vegetational and fire history: pollen, plant macrofossil and charcoal records from two Alaskan lakes
Postglacial vegetational and fire history: pollen, plant macrofossil and charcoal records from two Alaskan lakes
复制标题
冰河后植被和火灾历史：来自阿拉斯加两个湖泊的花粉、植物大化石和木炭记录
DOI：
10.1007/s00334-006-0052-z
复制
发表时间：
2006
影响因子：
2.5
通讯作者：
U. Krähenbühl
中科院分区：
文献类型：
--
作者：
W. Tinner;F. Hu;R. Beer;Petra Kaltenrieder;Brigitte Scheurer;U. Krähenbühl
阿拉斯加两个湖泊沉积物的孢粉、植物化石和木炭分析为推断晚冰期和全新世环境变化提供了新的资料。这些记录跨越了过去14,700年在洛斯特湖，240米a.s.l.，阿拉斯加中部，阿拉斯加山脉以北，灰熊湖9600年，海拔720米，铜河高原，阿拉斯加山脉南部。柳灌木在草本苔原上生长了大约14，400 calb.p.，白桦苔原形成于公元前2000年。在12，500 - 11，600 calb. p.，桦树覆盖减少，草本植物种类丰富度增加，虽然这些变化的时间没有很好的限制.杨扩展在11，200 calb.p.和形成密集的林，直到9600-9400 calb.p.当云杉glaucaforests或林地成为建立在这两个网站.在8500年前后，两个样地的绿桤木丰度都显著增加，标志着这些地区湖泊周围和山坡上桤木灌丛的发展. calb.p.at北方森林占主导地位的云杉在灰熊湖周围7200年和失落湖5700年建立。calb.p.at在灰熊湖，在过去的8500年里发生了明显的植被振荡; viridisexpanded在2750 calb.p.和450 calb.p.和下降，在150 calb.p.这些振荡与大规模的气候事件相吻合，如小冰期冷却（LIA），他们可能反映了植被对气候变化的敏感性在这个高的网站。显微镜木炭在Lost湖表明，火是重要的，在晚冰期桦树苔原，可能是因为严重的水分不足的区域气候和/或高丰度的精细燃料。根据Grizzly湖的微观木炭记录，在8500 - 6800 calb.p.和450 - 150 calb.p.之间，区域火灾是常见的。mariana，5500 ~ 3900 calb. p. whenP. mariana2. glauca和3900年后的200年calb.p.in bothP.格劳卡和P.马里亚纳群岛的森林灰熊湖花粉和显微炭的相关性分析表明，火灾活动的增加导致P。glauca、P. mariana和treeBetulain与A. viridis、柳叶菜属（Epilobium）、石松属（Lycopodium clavatum）和L.注释。
Pollen, plant macrofossil and charcoal analyses of sediments from two Alaskan lakes provide new data for inferring Lateglacial and Holocene environmental change. The records span the past 14,700 years at Lost Lake, 240 m a.s.l., central Alaska, north of the Alaska Range and 9600 years at Grizzly Lake, 720 m a.s.l., Copper River Plateau, south of the Alaska Range.Salixshrubs expanded in the herb tundra about 14,400 calb.p., andBetulashrub tundra became established at ca. 13,200 calb.p.DiminishedBetulashrub cover in association with the increased abundance of herbaceous taxa occurred at 12,500–11,600 calb.p., although the timing of these changes is not well constrained.Populusexpanded at 11,200 calb.p.and formed dense stands until 9600–9400 calb.p.whenPicea glaucaforests or woodlands became established at both sites. The abundance ofAlnus viridisincreased markedly around 8500 calb.p.at both sites, marking the development of alder shrub thickets around the lakes and on mountain slopes in these areas. Boreal forests dominated byPicea marianabecame established around 7200 calb.p.at Grizzly Lake and 5700 calb.p.at Lost Lake. At Grizzly Lake, marked vegetational oscillations occurred within the past 8500 years; for example,A. viridisexpanded at 2750 calb.p.and 450 calb.p.and declined at 150 calb.p.Some of these oscillations coincide with large-scale climatic events, such as the Little Ice Age cooling (LIA), and they probably reflect vegetational sensitivity to climatic change at this high site. Microscopic charcoal at Lost Lake suggests that fire was important in the lateglacial birch tundra, probably because of severe moisture deficits of the regional climate and/or high abundance of fine fuels. On the basis of the Grizzly Lake microscopic charcoal record, regional fires were common between 8500 and 6800 calb.p.and between 450 and 150 calb.p.Around Grizzly Lake, the mean return intervals of local fires estimated from macroscopic charcoal were ∼386 years between 6800 and 5500 calb.p.whenPicea glaucadominated overP. mariana, ∼254 years between 5500 and 3900 calb.p.whenP. marianawas more abundant thanP. glauca, and ∼200 years after 3900 calb.p.in bothP. glaucaandP. marianadominated forests. Correlation analysis of pollen and microscopic charcoal at Grizzly Lake reveals that increased fire activity led to the reductions ofP. glauca,P. mariana, and treeBetulain association with the expansions ofA. viridis, Epilobium, Lycopodium clavatum,andL. annotinum.