This paper presents two new pollen records and quantitative climate reconstructions from northern Chukotka documenting environmental changes over the last 27.9 ka. Open tundra- and steppe-like habitats dominated between 27.9 and 18.7 cal. ka BP. Betula and Alnus shrubs might have grown in sheltered microhabitats but disappeared after 18.7 cal. ka BP. Although the climate was rather harsh, local herb-dominated communities supported herbivores as is evident by the presence of coprophilous spores in the sediments. The increase in Salix and Cyperaceae ~16.1 cal. ka BP suggests climate amelioration. Shrub Betula appeared ~15.9 cal. ka BP, and became dominant after ~15.52 cal. ka BP, whilst typical steppe communities drastically reduced. Very high presence of Botryococcus in the Lateglacial sediments reflects widespread shallow habitats, probably due to lake level increase. Shrub Alnus became common after ~13 cal. ka BP reflecting further climate amelioration. Simultaneously, herb communities gradually decreased in the vegetation reaching a minimum ~11.8 cal. ka BP. A gradual decrease of algae remains suggests a reduction of shallow-water habitats. Shrubby and graminoid tundra was dominant ~11.8–11.1 cal. ka BP, later Salix stands significantly decreased. The forest-tundra ecotone established in the Early Holocene, shortly after 11.1 cal. ka BP. Low contents of green algae in the Early Holocene sediments likely reflect deeper aquatic conditions. The most favourable climate conditions were between ~10.6 and 7 cal. ka BP. Vegetation became similar to the modern after ~7 cal. ka BP but Pinus pumila came to the Ilirney area at about 1.2 cal. ka BP. It is important to emphasize that the study area provided refugia for Betula and Alnus during MIS 2. It is also notable that our records do not reflect evidence of Younger Dryas cooling, which is inconsistent with some regional environmental records but in good accordance with some others.

中文翻译：

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从 Ilirney 湖和 Rauchuagytgyn 花粉记录推断楚科奇（远东俄罗斯）西北部的晚更新世至全新世植被和气候变化

本文介绍了楚科奇北部的两个新花粉记录和定量气候重建，记录了过去 27.9 ka 的环境变化。开放的苔原和草原般的栖息地占主导地位，介于 27.9 和 18.7 cal 之间。卡 BP。桦树和桤木灌木可能生长在隐蔽的微生境中，但在 18.7 卡路里后消失。卡 BP。虽然气候相当恶劣，但当地以草本植物为主的社区支持食草动物，沉积物中存在嗜粪孢子就证明了这一点。Salix和 Cyperaceae的增加~16.1 cal。ka BP 建议气候改善。灌木桦木出现~15.9 cal。ka BP，并在~15.52 cal后成为主导。ka BP，而典型的草原社区急剧减少。晚冰期沉积物中葡萄球菌的大量存在反映了广泛的浅层栖息地，可能是由于湖泊水位增加。约 13 cal 后，灌木Alnus变得普遍。ka BP 反映了进一步的气候改善。同时，植被中的草本群落逐渐减少，达到最低~11.8 cal。卡 BP。藻类残留物的逐渐减少表明浅水栖息地的减少。灌木和禾本科苔原占主导地位~11.8-11.1 cal。ka BP，后来的Salix站位明显下降。在 11.1 cal 之后不久，在全新世早期建立的森林-苔原交错带。卡 BP。全新世早期沉积物中绿藻含量低可能反映了更深的水生条件。最有利的气候条件在~10.6 到 7 卡路里之间。卡 BP。大约 7 卡路里后，植被变得与现代相似。ka BP 但Pinus pumila以约 1.2 cal 的热量来到 Ilirney 地区。卡 BP。需要强调的是，研究区在 MIS 2 期间为Betula和Alnus提供了避难所。另外值得注意的是，我们的记录并未反映 Younger Dryas 冷却的证据，这与某些区域环境记录不一致，但与其他一些记录相吻合.