Abstract Arctic hotspots, local areas of high biodiversity, are potential key sites for conservation of Arctic biodiversity. However, there is a need for improved understanding of their long-term resilience. The Arctic hotspot of Ringhorndalen has the highest registered diversity of vascular plants in the Svalbard archipelago, including several remarkable and isolated plant populations located far north of their normal distribution range. Here we analyze a lake sediment core from Ringhorndalen for sedimentary ancient DNA (sedaDNA) and geochemical proxies to detect changes in local vegetation and climate. Half of the plant taxa appeared already before 10,600 cal. yr BP, indicating rapid colonization as the ice retreated. Thermophilous species had a reoccurring presence throughout the Holocene record, but stronger signal in the early than Late Holocene period. Thus, thermophilous Arctic plant species had broader distribution ranges during the Early Holocene thermal maximum c. 10,000 cal. yr BP than today. Most of these thermophilous species are currently not recorded in the catchment area of the studied lake, but occur locally in favourable areas further into the valley. For example, Empetrum nigrum was found in >40% of the sedaDNA samples, whereas its current distribution in Ringhorndalen is highly restricted and outside the catchment area of the lake. Our findings support the hypothesis of isolated relict populations in Ringhorndalen. The findings are also consistent with main Holocene climatic shifts in Svalbard identified by previous studies and indicate an early warm and species-rich postglacial period until c. 6500 cal. yr BP, followed by fluctuating cool and warm periods throughout the later Holocene.

中文翻译：

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完整的全新世湖泊沉积物古代 DNA 记录揭示了斯瓦尔巴群岛北部长期存在的高北极植物多样性热点

摘要 北极热点地区是生物多样性较高的地方，是保护北极生物多样性的潜在重点地区。但是，需要更好地了解他们的长期复原力。Ringhorndalen 的北极热点在斯瓦尔巴群岛拥有最高的维管植物多样性，包括位于其正常分布范围以北的几个显着和孤立的植物种群。在这里，我们分析了来自 Ringhorndalen 的湖泊沉积物核心的沉积古 DNA (sedaDNA) 和地球化学代理，以检测当地植被和气候的变化。一半的植物分类群在 10,600 卡路里之前已经出现。yr BP，表明随着冰的消退，快速定植。嗜热物种在整个全新世记录中反复出现，但在早期比全新世晚期信号更强。因此，在全新世早期热最大值 c 期间，嗜热的北极植物物种具有更广泛的分布范围。10,000 卡路里 年 BP 比今天。大多数这些嗜热物种目前没有记录在所研究湖泊的集水区，而是局部出现在更靠近山谷的有利区域。例如，在超过 40% 的 sedaDNA 样本中发现了 Empetrum nigrum，而其目前在 Ringhorndalen 的分布受到高度限制，并且在湖的集水区之外。我们的研究结果支持了 Ringhorndalen 孤立遗迹种群的假设。这些发现也与先前研究确定的斯瓦尔巴群岛全新世的主要全新世气候变化一致，并表明一个早期的温暖和物种丰富的冰后时期，直到 c。6500 卡路里 年血压，