Laguna Santa Elena (8.9290° N, 82.9257° W, 1055 m a.s.l.) is a small lake in the Diquís archaeological sub-region of southern Pacific Costa Rica. Previous analyses of pollen and charcoal in a sediment core from Santa Elena revealed a nearly 2,000 year history of vegetation change, maize cultivation and site occupation that is consistent with the archaeological record from the lake basin and surrounding area. Here we present the results of new loss-on-ignition, geochemical and bulk stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analyses of the Santa Elena sediments that supplement and refine the previous reconstruction. Like many lakes in Central America and the Caribbean, Laguna Santa Elena was a magnet for humans throughout its history. As a result, the lake experienced vegetation modification by humans and maize cultivation at varying intensities over a long duration. The Santa Elena sediments provide a record of palaeoenvironmental change during times of major culture change and increasing cultural complexity in the Diquís region, which occurred during intervals of broader changes driven by external forcing mechanisms, including the Terminal Classic Drought (TCD), the Little Ice Age (LIA) and the Spanish Conquest. Our high resolution lake sediment study from Santa Elena reveals details of these events at the local scale that are unobtainable by other means, including the timing of the initial intensification of maize cultivation at ca. 1,570 cal bp (ad 380) and two intervals of population decline coinciding with the TCD at ca. 1,085 cal bp (ad 865) and near the start of the LIA at ca. 683 cal bp (ad 1267).

中文翻译：

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哥斯达黎加南部拉古纳圣埃伦娜的植被历史和土地利用变化的稳定同位素分析

拉古纳·圣埃琳娜（8.9290°N，82.9257°W，1055 m asl）是位于哥斯达黎加南部太平洋Diquís考古分区的一个小湖。先前对圣埃伦娜（Santa Elena）沉积物核心中的花粉和木炭的分析显示，近2000年的植被变化，玉米种植和场地占用的历史与湖盆和周边地区的考古记录一致。这里，我们提出新的损失上点火，地球化学和散装稳定碳的结果（δ ¹³ C）和氮（δ ¹⁵N）对圣埃伦娜沉积物的同位素分析，可补充和完善先前的重建工作。像中美洲和加勒比海的许多湖泊一样，拉古纳·圣埃琳娜岛在整个历史上一直吸引着人类。结果，该湖在长时间内经历了人类和玉米种植在不同强度下的植被改造。圣埃伦娜（Santa Elena）沉积物记录了迪奎斯地区主要文化变化和文化复杂性增加期间的古环境变化，这是在外部强迫机制（包括终端经典干旱（TCD），小冰）驱动的更广泛变化期间发生的年龄（LIA）和西班牙人征服。我们对圣埃伦娜（Santa Elena）进行的高分辨率湖泊沉积物研究揭示了这些当地事件的细节，而这些细节是其他方法无法实现的，包括大约在2000年开始加强玉米种植的时间。1,570卡路里bp（ad 380）和人口下降的两个时间间隔与TCD大约相符。1,085 cal bp（ad 865），并且在LIA附近开始。683 cal bp（ad 1267）。