Increasing human activities during the past 2,100 years in southwest China inferred from a fossil pollen record
Increasing human activities during the past 2,100 years in southwest China inferred from a fossil pollen record
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从花粉化石记录推断，过去2100年来中国西南地区人类活动不断增加
DOI：
10.1007/s00334-020-00799-7
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发表时间：
2021
影响因子：
2.5
通讯作者：
Yong Wang
中科院分区：
文献类型：
--
作者：
Ying Xie;Yongbo Wang;Xingqi Liu;Ji Shen;Yong Wang
除了自然气候变化外，人类活动也会引起区域植被组成的显著变化，特别是在全新世晚期。中国西南地区在森林砍伐和农业开发方面经历了漫长的人类活动历史。本文通过对云南北海湿地2,100多年来连续的花粉化石记录的研究，旨在更好地了解该地区的植被历史和潜在的人类活动。花粉分析结果表明，森林组成呈减少趋势，包括以赤杨属为主的落叶阔叶林和以万年青栎属为代表的万年青阔叶林。另一方面，禾本科和蒿属等草本植物随着森林的衰落而沿着扩张，尤其是在公元1120年以后。排序分析的结果进一步证实了这样一种模式，其中第一个主成分（PC 1，捕获总方差的42.2%）代表了一个增加的趋势，这是随后解释为人类活动的指数。我们的研究结果显示了与以前发表的云南沉积记录以及历史文献大致相同的模式。随着区域人口的增长，人类活动增加，森林砍伐和区域农业发展。它们也可能导致了草本植物的扩张，尤其是禾本科植物，取代了森林。因此，北海湿地的花粉化石记录表明，中国西南地区的人类活动在过去的2,100年中逐渐增加，并在公元1120年后迅速增加。沉积物流入和粒度分析的结果显示，一般一致的模式与夏季季风的迹象捕获的稳定氧同位素记录从石笋，表明有限的影响，从人类活动的湿地系统内的区域景观相比。
Besides natural climate variations, human activities can also cause significant changes in regional vegetation composition, especially during the late Holocene period. Southwest China has experienced a long history of human activities in terms of deforestation and agricultural development. Here we present a continuous fossil pollen record covering the past 2,100years from Beihai Wetland in western Yunnan Province, for a better understanding of regional vegetation history and potential human activities. The pollen results indicate that the forest components show decreasing trends, including Alnus dominated deciduous broadleaved forest and evergreen broadleaved forest represented by evergreen Quercus. On the other hand, herbs such as Poaceae and Artemisia expanded along with the decline of forest, especially during the period after ad 1120. The results of ordination analysis further confirm such a pattern in which the first PCA component (PC1, capturing 42.2% of total variance) represents an increasing trend, which is subsequently interpreted as an index of human activities. Our findings show broadly identical patterns to previously published sedimentary records from Yunnan as well as historical documents. The human activities increased following the expansion in regional population, in the form of deforestation and regional agricultural development. They may also have caused the expansion of herbs, especially Poaceae, which replaced forest. Therefore, as indicated by the fossil pollen record from the Beihai Wetland, human activities in southwest China increased gradually during the past 2,100years and more rapidly after ad 1120. Results of sediment influx and grain size analyses showed generally consistent patterns with the signs of summer monsoons captured by stable oxygen isotope records from stalagmites, indicating limited influence from human activities within the wetland system compared to the regional landscape.