Impacts of Norse settlement on terrestrial and aquatic ecosystems in Southwest Iceland
Impacts of Norse settlement on terrestrial and aquatic ecosystems in Southwest Iceland
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DOI：
10.1007/s10933-020-00169-3
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发表时间：
2021-01
影响因子：
2.1
通讯作者：
N. Richter;J. Russell;J. Garfinkel;Yongsong Huang
中科院分区：
文献类型：
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作者：
N. Richter;J. Russell;J. Garfinkel;Yongsong Huang
公元第一个千年，北欧人对北大西洋岛屿的殖民导致了这些以前“原始”景观的剧烈史前环境变化。在冰岛，挪威人的定居与桦树的迅速减少和土壤侵蚀加剧有关，然而，挪威人在北大西洋勘探的时间恰逢气候大变化，这也影响了冰岛的环境。迄今为止，几乎没有记录将气候和人类对陆地生态系统的影响分开，而且关于挪威人的到来对冰岛水生生态系统的影响的研究也很少。在这里，我们使用来自冰岛西南部Vestra Gíslholtsvatn （VGHV）的高分辨率湖泊沉积物记录来研究过去2000年的这些过程。挪威人到达冰岛（约公元870年）之后，沉积速率迅速增加，树叶蜡烷烃的变化表明树木减少，草类增加。这一转变与湖沼学变化相一致，包括初级生产力（即c17正烷烃和生物源蛋白石通量）的增加和栖藻群落的变化。其中许多变化今天仍然很明显。与VGHV和海表温度记录重建的冬春季烯烃温度相比，这一时期陆地和水生生态变化与气候之间几乎没有相关性。同样，VGHV记录的火山爆发与任何长期环境变化无关。相反，VGHV记录表明，人类住区对VGHV集水区和湖泊生态系统的变化产生了持久的影响。
Norse colonization of North Atlantic islands in the 1st millennium of the Common Era led to drastic prehistoric environmental changes in these previously “pristine” landscapes. In Iceland, Norse settlement is associated with a rapid decline in birch trees and heightened soil erosion, yet the timing of Norse exploration in the North Atlantic coincided with large climate changes that also influenced Icelandic environments. To date, there are few records that disentangle climatic and human impacts on terrestrial ecosystems, and there has been very little work on the impacts of Norse arrival on Iceland’s aquatic ecosystems. Here we use a high-resolution lake-sediment record from Vestra Gíslholtsvatn (VGHV), southwest Iceland to investigate these processes during the last 2,000 years. Norse arrival (c. 870 CE) in Iceland is followed by a rapid increase in sedimentation rate and a transition in leaf waxn-alkanes indicating a decrease in trees and expansion of grasses. This transition coincides with limnological changes, including increased primary productivity (i.e. C17n-alkane and biogenic opal fluxes) and shifts in the haptophyte algal community. Many of these changes are still apparent today. Comparisons with a new winter-spring alkenone temperature reconstruction from VGHV and marine sea surface temperature records show little to no correlation between terrestrial and aquatic ecological changes and climate at this time. Similarly, volcanic eruptions recorded in VGHV are not associated with any long-term environmental changes. Rather, the VGHV record suggests that human settlement had a lasting impact on the catchment area of VGHV and changes within the lake ecosystem.