Putting Human Exploitation of Marine Resources in Temporal and Environmental Context

把人类对海洋资源的开发置于时间和环境背景下广泛存在的证据表明，在过去的几千年里，人类在加利福尼亚沿海地区加强了对资源的利用。这包括从全新世早期的内陆觅食到全新世中期利用海洋贝类、鱼类和哺乳动物的转变。公元前1000年左右，人类的觅食方式再次发生变化，从依赖沿海资源转向内陆资源。大约在同一时间，以前在加利福尼亚中部和北部常见的北方毛皮海豹从加利福尼亚中部的考古遗址中消失了，再也没有出现在土著遗址中。这些定居和生存的变化被一些人解释为人口增长导致资源枯竭的结果。相比之下，在圣巴巴拉地区工作的研究人员认为，全新世晚期的转变是气候驱动的，那里有完整的降雨、海洋温度和上升流强度变化记录。这一论点是将美国西南部人类生态变化与中世纪气候异常联系起来的更广泛辩论的一部分。这个论点最近被扩展到解释人类和海洋哺乳动物在加利福尼亚中部的迁移，但是这个地区的高时间分辨率的古气候数据很少，或者更北的地区，在历史时期，那里的北方海狗被捕获。早在全新世中期（公元前6000年）就开始向沿海资源的集约利用转变的时间也很有趣。在全球其他地方，越来越多的证据表明，此时海洋环流和全球气候正在发生变化，这可能与现代厄尔尼诺/拉尼娜气候周期的开始有关。目前，缺乏来自加利福尼亚中部和北部海岸的完整的古环境数据。因此，不可能确定人类住区和资源利用的变化是否是气候强迫的结果。在我们的多学科项目中，我们将使用考古材料的直接14C AMS日期来构建精细纹理的时间框架，用于研究加利福尼亚中部和北部海岸的文化，古生态和古气候变化。我们有几个目标。软体动物壳的化学和同位素变化将是过去海洋状况的关键信息来源。同样，海洋哺乳动物的同位素变化可以揭示迁徙模式和营养动力学，以及它们如何随着推断的气候变化而变化。因此，我们将重点研究这些材料的年代。我们期望得到以下结果：1)构建来自加利福尼亚中部和北部的软体动物壳的时间序列，这将构成未来古气候研究的基础；2)评估加利福尼亚许多考古遗址的地层关系是否可靠，或者它们是否受到动物挖洞和翻动的干扰；3)关于这两个地区海洋哺乳动物动物群和人类群落变化时间的精确信息。一旦我们建立了一个可靠的年代框架，就会进行详细的同位素和动物分析。

Putting Human Exploitation of Marine Resources in Temporal and Environmental ContextByPaul L. KochDiane Gifford-Gonzalez Widespread evidence exists for intensified resource use by humans in coastal California over the past several thousand years. This includes a shift from inland foraging in the early Holocene to use of marine shellfish, fish, mammals in the middle Holocene. Around 1000 B.P., human foraging changed again, shifting away from reliance on coastal resources to those of the interior. Around the same time, the northern fur seal, formerly common in central and northern California, disappeared from central California archaeological sites, never to reappear in aboriginal sites. These changes in settlement and subsistence have been interpreted by some as the result of resource depression caused by growing human populations. In contrast, researchers working in the Santa Barbara region, where there is a well developed record of Holocene variations in rainfall, ocean temperature, and upwelling intensity, contend that the late Holocene shift was climatically driven. This argument is part of a broader debate that links changes in human ecology in the southwestern U.S. to the Medieval Climatic Anomaly. This argument has recently been extended to explain human and marine mammal shifts in central California, but little paleoclimatic data at high-temporal resolution exist for this region, or for the region farther north, where northern fur seals were harvested into historic times. The timing of the earlier shift to intensified use of coastal resources in the middle Holocene (6000 B.P.) is intriguing as well. Elsewhere on the globe, evidence is mounting for a shift in ocean circulation and global climate at this time, perhaps relating to the onset of modern El Nino/La Nina climatic cycles. At present, well-constrained paleoenvironmental data from the central and northern California coast are lacking. Thus it is impossible to determine if changes in human settlement and resource use are the result of climatic forcing. In our multidisciplinary project, we will use direct 14C AMS dates of archaeological materials to construct a finely-textured temporal framework for the study of cultural, paleoecologic, and paleoclimatic changes on the central and northern California coast. We have several goals. Chemical and isotopic variations in mollusk shells will be a key source of information on past ocean conditions. Likewise, isotopic variations in marine mammals can reveal migration patterns and trophic dynamics, and how they changed with inferred changes in climate. As a consequence, we will focus our dating efforts on these materials. We anticipate the following results: 1) construction of a time series of mollusk shells from both central and northern California that will form the basis of future paleoclimatic research, 2) an assessment of whether or not stratigraphic relations at a number of California archaeological sites are reliable, or if they have been perturbed by animals burrowing and churning, and 3) precise information on the timing of changes in the marine mammal fauna and human communities in both regions. Detailed isotopic and faunal analyses will be conducted once we've established a robust chronologic framework.