When was the South Pacific colonised? A lake sediment approach to understanding climate:human drivers of ecosystem change on remote Pacific Islands

太平洋上的波利尼西亚群岛是地球上最后一批人类殖民的地方之一。殖民化的确切日期是有争议的——这种情况源于不同的证据来源（1,2）。来自库克群岛（阿提乌岛、曼加亚岛）、萨摩亚群岛（乌波卢岛）和汤加的新湖泊沉积物记录显示了非常明确的干扰证据，但尚不清楚的是，这些信号在多大程度上代表了人类的到来或气候的变化(2)。分析沉积记录的一个关键问题是在时间和空间范围内区分太平洋岛屿环境的自然变化与人类到达所引起的变化的能力。我们的目标是使用基于SedDNA、脂质生物标志物、化石木炭和保存在湖泊沉积物中的花粉的多代理方法来确定：a)人类和/或牲畜的存在，以及b)相关的环境变化。在统计分析的支持下，将在四个地点部署多代理方法，我们已经有了良好的时间控制和高分辨率的古气候记录。我们处于有利地位，可以应用新的方法和更高分辨率的分析来解决有关太平洋偏远岛屿对气候和人类力量的反应的基本问题。

The Pacific islands of Polynesia were among the last places on earth to be colonised by humans. The precise dates of colonisation are debated - a situation which arises from the different sources of evidence (1, 2). New lake sediment records from the Cook Islands (Atiu, Mangaia) and Samoa (Upolu) and Tonga show very clear evidence of disturbance, but what is unclear is to what extent the signal represents the arrival of humans or a change in climate (2). A key question for the analysis of sedimentary records is the ability to distinguish natural variability in the environment of Pacific Islands from that arising from the arrival of humans in a temporal and spatial context. We aim to use a multi-proxy approach based on SedDNA, lipid biomarkers, fossil charcoal, and pollen preserved in lake sediments to identify: a) the presence of humans and/or livestock that were brought with them, and b) the related environmental change. Multiproxy approaches supported by statistical analysis, will be deployed to four sites where we already have good chronological controls and high resolution records of palaeoclimate. We are well placed to apply new methods and higher resolution analyses to address fundamental questions about the response of remote pacific islands to climate and human forcings.