Data from: Compositional and functional shifts in arctic fungal communities in response to experimentally increased snow depth

Climate warming leads to more intensive evaporation from the Arctic sea resulting in increased precipitation in the low Arctic, e.g., higher snowfall during winter. Deeper snow keeps the arctic soils warmer and alters soil attributes and vegetation, e.g., increase in nitrogen availability, expansion of shrubs and decline in shade-intolerant lichens and bryophytes. Changes in soil properties and vegetation are expected to influence on saprotrophic and plant-symbiotic fungi, but how increased snow depth affects their community composition remain unknown. In the present work, we used DNA metabarcoding to study the effects of long-term experimental manipulations of snow depth on soil fungal communities in dry heath and moist tussock tundra in Arctic Alaska. We report strong changes in fungal community compositions in the two tundra types, with pronounced declines observed in the majority of fungal functional guilds, including ectomycorrhizal, lichenized, plant pathogenic, saprotrophic and bryophyte-associated species. The observed changes in lichenized and bryophyte-associated fungi are in agreement with previously published above-ground changes, i.e. decrease of lichen and bryophyte cover and diversity. However, the majority of observed trends, including the decline of ectomycorrhizal fungi (that were anticipated to benefit from the expansion of their host plants), suggest that changes in fungal communities do not entirely correspond to and are not primarily driven by shifts in vegetation. Instead, arctic fungal communities appear to exhibit faster turnover that may be influenced by dynamic interactions with numerous biotic and abiotic factors, e.g., soil nutrient cycling and community dynamics in other groups of soil microorganisms. We highlight the importance of “below-ground studies” in assessing ecosystem responses to climatic changes, because faster turnover of microbial communities may be applicable for monitoring early-stage alterations caused by climatic changes.

气候变暖导致北极海域蒸发强度增大，进而使北极低纬地区降水增多，例如冬季降雪量增加。较厚的积雪会使北极土壤维持较高温度，并改变土壤属性与植被特征：土壤氮素有效性提升、灌木群落扩张，以及不耐阴地衣（lichens）和苔藓植物（bryophytes）的丰度下降。土壤属性与植被的变化预计会影响腐生真菌（saprotrophic fungi）和植物共生真菌，但积雪深度增加如何改变它们的群落组成仍不明确。本研究采用DNA元条形码（DNA metabarcoding）技术，探究了长期积雪深度人工调控对阿拉斯加北极地区干石南荒原与湿润丛状苔原土壤真菌群落的影响。研究发现，两种苔原类型的真菌群落组成均发生显著改变，多数真菌功能类群均出现明显衰退，包括外生菌根真菌（ectomycorrhizal fungi）、地衣共生真菌（lichenized fungi）、植物病原真菌、腐生真菌以及苔藓植物伴生真菌。本次观测到的地衣共生真菌与苔藓植物伴生真菌的变化趋势，与此前已发表的地上部分研究结果一致，即地衣和苔藓植物的盖度与多样性均出现下降。然而，多数观测到的变化趋势——包括原本被认为会因宿主植物扩张而获益的外生菌根真菌的衰退——表明真菌群落的变化并不完全与植被演替相匹配，且并非主要由植被变化驱动。与之相反，北极真菌群落似乎具有更快的周转速率，这一过程可能受到众多生物与非生物因素的动态互作影响，例如土壤养分循环以及其他土壤微生物类群的群落动态。本研究强调了‘地下研究’在评估生态系统对气候变化响应中的重要性，因为微生物群落的快速周转可用于监测气候变化引发的早期生态系统变化。