ABSTRACT

Climate change causes Arctic glaciers to retreat faster, exposing new areas for colonization. Several pioneer plants likely to colonize recent deglaciated, nutrient-poor areas depend on fungal partners for successful establishment. Little is known about general patterns or characteristics of facilitating fungal pioneers and how they vary with regional climate in the Arctic. The High Arctic Archipelago Svalbard represents an excellent study system to address these questions, as glaciers cover ∼60% of the land surface and recent estimations suggest at least 7% reduction of glacier area since 1960s. Roots of two ectomycorrhizal (ECM) plants (Salix polaris and Bistorta vivipara) were sampled in eight glacier forelands. Associated ECM fungi were assessed using DNA metabarcoding. About 25% of the diversity was unknown at family level, indicating presence of undescribed species. Seven genera dominated based on richness and abundance, but their relative importance varied with local factors. The genus Geopora showed surprisingly high richness and abundance, particularly in dry, nutrient-poor forelands. Such forelands will diminish along with increasing temperature and precipitation, and faster succession. Our results support a taxonomical shift in pioneer ECM diversity with climate change, and we are likely to lose unknown fungal diversity, without knowing their identity or ecological importance.

中文翻译：

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高北极地区的冰川退缩：外生菌根多样性的机会还是威胁？

摘要

气候变化使北极冰川退缩得更快，从而暴露了新的殖民地。几种可能在近期冰冻，缺乏营养的地区定居的先锋植物依靠真菌伴侣成功建立。关于促进真菌先锋的一般模式或特征以及它们如何随北极地区气候变化而知之甚少。北极高群岛群岛是解决这些问题的一个极好的研究系统，因为冰川覆盖了约60％的陆地表面，最近的估计表明自1960年代以来冰川面积至少减少了7％。两种外生菌根（ECM）植物（极地柳和白僵菌）的根）在八个冰川前陆采样。使用DNA元条形码评估相关的ECM真菌。在家庭层面，大约25％的多样性是未知的，表明存在未描述的物种。七属以丰富度和丰度为基础，但它们的相对重要性随当地因素而变化。Geopora属显示出惊人的高丰度和丰度，特别是在干旱且营养不良的前陆地区。随着温度和降水的增加以及更快速的演替，这些前陆将会减少。我们的研究结果支持了先驱ECM多样性随着气候变化而发生的分类学转变，而且我们很可能会失去未知的真菌多样性，而又不知道它们的身份或生态重要性。