Abstract The Steppe Altai is a natural transition zone between the Central Asian steppes and deserts and the Siberian taiga. Various lakes located in the Kulunda lowland, the biggest part of the Steppe Altai, provide a unique archive of the environmental history of the Altai Mountain piedmont and adjacent plains. Palaeorecords from two lakes, Maloye Yarovoye and Kuchuk, provide the longest high-resolution records of the Steppe Altai and south-western Siberia, allowing us to describe the environmental history of the region with high accuracy since the last deglaciation. The main objective of this study was to establish the interrelationship between plant biodiversity, climate, and fire dynamics in the Steppe Altai from postglacial time to present day. We used several techniques for this task, including pollen and geochemical analyses, quantitative reconstruction of climate and biodiversity using multivariate statistics, and estimation of macrocharcoal accumulation rates and sources of fuel. Based on analyses of the two palaeorecords, we conclude that plant diversity and evenness show a strong positive correlation with annual precipitation. Pinus sylvestris spread throughout Kulunda lowland after 10.8 ka BP, and maximal spread of mixed coniferous-deciduous forests in south-western Siberia occurred between 7.2 and 2.7 ka BP. We propose that the maximum development of the ribbon-like forests dominated by Scotch pine characterized the Steppe Altai at that time. Forest fires occurred sparsely during the Holocene but were not inherent in pre-Holocene time. Before 650 CE, the main fuel for the fire was grass; however, forest fires rapidly increased in the Steppe Altai after 650 CE and prevailed over steppe fires after 1420 CE. Increased fire activity over the last millennium was likely human-induced.

中文翻译：

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阿尔泰草原的冰后历史：气候、火灾和植物多样性

摘要 阿尔泰草原是中亚草原和沙漠与西伯利亚针叶林之间的天然过渡带。位于阿尔泰草原最大部分库伦达低地的各种湖泊为阿尔泰山山麓和邻近平原的环境历史提供了独特的档案。来自 Maloye Yarovoye 和 Kuchuk 两个湖泊的古记录提供了阿尔泰草原和西伯利亚西南部最长的高分辨率记录，使我们能够高精度地描述自上次冰川消退以来该地区的环境历史。本研究的主要目的是确定阿尔泰草原从冰后时期到现在的植物生物多样性、气候和火灾动态之间的相互关系。我们使用了多种技术来完成这项任务，包括花粉和地球化学分析，使用多变量统计数据对气候和生物多样性进行定量重建，并估计巨量碳积累率和燃料来源。基于对两个古记录的分析，我们得出结论，植物多样性和均匀度与年降水量呈强正相关。樟子松在 10.8 ka BP 后遍布库伦达低地，西伯利亚西南部针叶-落叶混交林的最大扩散发生在 7.2 至 2.7 ka BP 之间。我们认为当时以苏格兰松为主的带状森林的最大发展是阿尔泰草原的特征。森林火灾在全新世期间很少发生，但在全新世之前并不是固有的。公元650年之前，火的主要燃料是草；然而，公元 650 年之后，阿尔泰草原的森林火灾迅速增加，公元 1420 年之后，草原火灾占了上风。过去一千年中火灾活动的增加很可能是人为引起的。