Hidden Frontiers: longitudinal crop trajectories in the Alpine Arc

据预测，气候变化将对全球农业产生负面影响，如果我们要防止作物系统性歉收，当务之急是尽我们所能更好地了解作物适应性和可能需要的农业管理干预措施。当我们经常想到气候变化对今天和未来的影响时，史前社会也经历了气候的重大变化。在这个项目中，我们使用基于科学的考古学来调查这些过去的变化，以了解古代农业社区及其作物如何应对气候变化。这些关于过去农业的信息将有助于科学界更好地了解我们可能面临的风险以及管理我们的农业系统可能需要的可能的应对措施。《隐藏的边疆》关注的是环阿尔卑斯地区过去的农业。阿尔卑斯山脉，特别是其举世闻名的史前阿尔卑斯堆屋，为评估作物如何应对气候变化提供了绝佳的机会。这些地点为了解气候如何影响农业提供了三个关键资源：-保存植物遗骸及其DNA。阿尔卑斯山脉拥有一些欧洲最原始的古代植物标本，这要归功于联合国教科文组织列出的111个桩居遗址中的许多水下保存。这些遗址也被称为古湖村，在公元前五千年到公元前一千年之间由农民定居，跨越了新石器时代、青铜时代和铁器时代。这些遗址建在木桩上，被打入沼泽地，但随着时间的推移，这些遗址被遗弃，并被建造它们的湖泊淹没。由于水下环境，有机物质保存得非常好，考古学家可以通过识别种子和谷壳来推断不同时期种植的作物。这个项目的下一步是，使用最先进的方法直接从小麦和亚麻等物种的遗骸中恢复古代DNA，然后分析这些DNA，以了解作物运动、替换和适应的详细历史。——约会。在堆居遗址中，出色的树干有机保存使得史前考古学很少提供高分辨率的年代测定。利用“树木年代学”，研究人员仔细地描述了树木年轮生长的模式，允许这些地点以几十年为尺度进行测定，这超过了放射性碳定年法通常提供的分辨率。这些日期使该项目能够将考古植物遗迹与过去气候数据提供的严格年表联系起来。——古气候重建。几十年来，气候研究人员一直在阿尔卑斯山周围的湖泊上仔细研究这些桩式居住地。利用来自湖泊的沉积物岩心，研究人员通过测量稳定同位素、识别花粉类型和观察不同类型的淡水昆虫，已经能够追踪当地气候的变化。这些对过去气候的详细重建使该项目能够充分了解不同作物生长的环境条件，并评估气候变化时的遗传影响。通过这种非凡的资源组合，HIDDEN FRONTIERS探索了气候和社会的相互作用，以了解高山湖村庄及其粮食生产系统的故事。通过分析这些作物的古代DNA，研究小组确定了当地的作物谱系是否在具有挑战性的气候阶段灭绝了。此外，通过观察这些谱系中的特定基因，我们开始了解作物适应的速度有多快，以及哪些基因对新的适应最负责。这些发现将有助于预测我们的农业系统如何应对气候变化，从而使我们的社会采取必要措施，确保我们的作物能够养活未来的许多代人。

Climate change is predicted to negatively impact global agriculture, and if we are to prevent systemic crop failure, it is urgent to do all we can to better understand crop adaptability and the agriculture management interventions which may be required. While we often think of the impact of climate change for today and the future, prehistoric societies also experienced major variations in the climate. In this project we investigate these past changes using science-based archaeology to understand how ancient farming communities and their crops responded to climate variations. This information about agriculture in the past will help the scientific community better understand the risks we may face and possible responses which may be necessary to manage our agriculture systems. HIDDEN FRONTIERS focuses on past agriculture in the circum-Alpine region. The Alps--and specifically their world-famous prehistoric Alpine pile dwellings--provide the perfect opportunity to evaluate how crops responded to variation in climate. These sites provide three key resources to understand how climate impacts agriculture: - Preservation of plant remains and their DNA. The Alps possess some of Europe's most pristine ancient plant specimens, thanks to underwater preservation at many of the 111 UNESCO-listed pile dwelling sites. These sites, also referred to as the ancient Lake Villages, were settled by farmers between the fifth and first millennia BC, spanning the Neolithic, Bronze Age and Iron Age. The sites were built on wooden piles driven into marshy land, but over time the sites were abandoned and flooded by the lakes upon which they were constructed. Due to the underwater conditions, organic materials are exceptionally well preserved, allowing archaeologists to identify seeds and chaff to infer which crops were farmed in different periods. This project takes the next step, using state-of-the-art methods to recover ancient DNA directly from the remains of species like wheat and flax, and then analyse this DNA to understand a detailed history of crop movement, replacement and adaptation. - Dating. The excellent organic preservation of tree trunks at the pile dwelling sites enables high-resolution dating rarely afforded in prehistoric archaeology. Using "dendrochronology", researchers have carefully characterised patterns of tree ring growth, allowing for the sites to be dated on the scale of decades, which exceed the resolution normally provided by radiocarbon dating. These dates allow this project to link archaeological plant remains into a tight chronology informed by past climate data. - Paleoclimate reconstructions. The circum-Alpine lakes on which the pile dwelling sites were constructed have been carefully studied by climate researchers for decades. Using sediment cores from the lakes, researchers have been able to track local changes in the climate by measuring stable isotopes, identifying pollen types and observing different types of freshwater insects. These detailed reconstructions of past climates allow this project to fully appreciate the environmental conditions under which different crops were grown and evaluate the genetic impact when the climate changed. Through this remarkable combination of resources, HIDDEN FRONTIERS explores the interplay of climate and society to understand the story of Alpine Lake Villages and their food production systems. By analysing ancient DNA from the crops, the team identifies if local crop lineages went extinct during challenging climate phases. In addition, by looking at specific genes in these lineages, we come to understand how quickly crops can adapt and what genes are most responsible for new adaptations. These findings will be instrumental in predicting how our agricultural system may respond to climate change, thereby allowing our society to take the necessary steps to ensure our crops can feed many generations in the future.