A first empirical analysis of population stability in North America using radiocarbon records
A first empirical analysis of population stability in North America using radiocarbon records
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DOI：
10.1177/0959683620919975
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发表时间：
2020-05-19
期刊：
影响因子：
2.4
通讯作者：
Kelly, Robert L.
中科院分区：
文献类型：
--
作者：
Bird, Darcy;Freeman, Jacob;Kelly, Robert L.
关于动植物种群稳定性的问题是种群生态学的基础，但这并不是考古学家关注史前人类种群的研究课题。这是一个重要的知识差距。几十年到几个世纪以来人口的波动——人口不稳定——可能会限制人类经济的扩张。描述种群稳定性基本模式的第一步是确定随时间变化的波动大小，因为较小的波动比较大的波动更稳定。我们使用大陆规模的放射性碳数据集对北美人类社会的长期稳定性进行了生物地理学分析。我们的分析将经过校准的放射性碳日期概率分布 (SPD) 的稳定性与生存策略以及 6000 至 300 BP 之间的气候稳定性模型进行了比较。这种粗粒度的分析揭示了北美人类系统稳定性的总体趋势，未来的研究可能以此为基础。我们的结果表明，一般来说，农业序列比狩猎采集序列具有更稳定的 SPD，但农业序列也经历了在狩猎采集序列中未见的罕见、极端的 SPD 增加和减少。我们认为，农业的采用会带来意想不到的后果，即在大多数时间范围内增加人口密度和稳定性，但也增加了人口对大规模、罕见变化的脆弱性。相反，狩猎采集系统仍然灵活，不易受到大规模人口变化的影响。气候稳定性可能对长期人口稳定产生间接影响，在影响人口统计之前，气候冲击可能会通过生存策略的其他方面得到缓冲。
Questions regarding population stability among animals and plants are fundamental to population ecology, yet this has not been a topic studied by archeologists focusing on prehistoric human populations. This is an important knowledge gap. The fluctuation of human populations over decades to centuries - population instability - may constrain the expansion of human economies. A first step toward describing basic patterns of population stability would be to identify sizes of fluctuations through time, since smaller fluctuations are more stable than larger fluctuations. We conduct a biogeographic analysis of the long-term stability of human societies in North America using a continental scale radiocarbon dataset. Our analysis compares the stability of summed calibrated radiocarbon date probability distributions (SPDs) with subsistence strategies and modeled climate stability between 6000 and 300 BP. This coarse-grained analysis reveals general trends regarding the stability of human systems in North America that future studies may build upon. Our results demonstrate that agricultural sequences have more stable SPDs than hunter-gatherer sequences in general, but agricultural sequences also experience rare, extreme increases and decreases in SPDs not seen among hunter-gatherers. We propose that the adoption of agriculture has the unintended consequence of increasing population density and stability over most time scales, but also increases the vulnerability of populations to large, rare changes. Conversely, hunter-gatherer systems remain flexible and less vulnerable to large population changes. Climate stability may have an indirect effect on long-term population stability, and climate shocks may be buffered by other aspects of subsistence strategies prior to affecting human demography.