Pre-Columbian fire management and control of climate-driven floodwaters over 3,500 years in southwestern Amazonia
Pre-Columbian fire management and control of climate-driven floodwaters over 3,500 years in southwestern Amazonia
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DOI：
10.1073/pnas.2022206118
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发表时间：
2021-06
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影响因子：
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通讯作者：
N. Duncan;N. Loughlin;John H. Walker;Emma P. Hocking;B. Whitney
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作者：
N. Duncan;N. Loughlin;John H. Walker;Emma P. Hocking;B. Whitney
意义夏文人、莫切人、提瓦纳库人和印加人都是哥伦布时代前著名的文化，但与此同时，在亚马逊西南部，人们几千年来一直在改变着10万平方公里的土地。自20世纪60年代以来，莫霍斯大草原的土石方工程量已经变得清晰起来，但确定这些地物的年代一直很困难。我们发现，从至少3500年前开始，哥伦布以前的人们就开始使用水文工程和火来最大化水生和陆地资源。在17世纪，耶稣会传教带来的牛和新技术改变了这些景观的形式和功能。这些亚马逊土方工程的规模和古老程度需要与世界各地驯化的景观和文明进行比较。在支持经济和文化活动的景观中，人类社区在各种空间尺度上积极管理环境和环境变化，使大陆尺度气候的影响复杂化。在这里，我们展示了在亚马逊西南部全新世气候变化的背景下，人类是如何改变水文条件的。对从同一永久湿地(∼，相距22公里)内提取的两个沉积物岩芯进行的古生态调查(植物硅体、木炭、花粉、硅藻)表明，土地利用和管理的集约化发生的时间存在1,500年的差异，包括提高农田农业、火灾制度和农林业。尽管在全新世中后期降水量增加是众所周知的，但人类行为操纵了气候驱动的水文变化，揭示了不同的人类景观驯化历史。如果没有人类社区的调解，环境因素无法解释地方差异，人类社区至少在3500年前就开始将该地区转变为目前的稀树草原/森林/湿地镶嵌。区域环境变量没有驱动农民和渔民的选择，他们塑造了这些地方背景，以更好地管理资源开采。我们今天观察到的稀树草原是在后欧洲时期创建的，那里的火场制度和结构多样性是由养牛场塑造的。
Significance The Chavín, Moche, Tiwanaku, and Inka are well-known pre-Columbian cultures, but during the same time, in the southwestern Amazon, people were transforming a 100,000-km2 landscape over thousands of years. The extent of earthworks in the Llanos de Mojos has become clear since the 1960s, but dating these features has been difficult. We show that pre-Columbian people used hydrological engineering and fire to maximize aquatic and terrestrial resources beginning at least 3,500 years ago. In the 17th century CE, cattle and new technologies brought by Jesuit missions altered the form and function of these landscapes. The scale and antiquity of these Amazonian earthworks demand comparison with domesticated landscapes and civilizations from around the world. In landscapes that support economic and cultural activities, human communities actively manage environments and environmental change at a variety of spatial scales that complicate the effects of continental-scale climate. Here, we demonstrate how hydrological conditions were modified by humans against the backdrop of Holocene climate change in southwestern Amazonia. Paleoecological investigations (phytoliths, charcoal, pollen, diatoms) of two sediment cores extracted from within the same permanent wetland, ∼22 km apart, show a 1,500-y difference in when the intensification of land use and management occurred, including raised field agriculture, fire regime, and agroforestry. Although rising precipitation is well known during the mid to late Holocene, human actions manipulated climate-driven hydrological changes on the landscape, revealing differing histories of human landscape domestication. Environmental factors are unable to account for local differences without the mediation of human communities that transformed the region to its current savanna/forest/wetland mosaic beginning at least 3,500 y ago. Regional environmental variables did not drive the choices made by farmers and fishers, who shaped these local contexts to better manage resource extraction. The savannas we observe today were created in the post-European period, where their fire regime and structural diversity were shaped by cattle ranching.