Data from: The significance of retention trees for survival of ectomycorrhizal fungi in clear‐cut Scots pine forests

1. Forestry with short stand generations and simplified forest structures has markedly af-fected forest biodiversity. One group of organisms adversely affected by clear-cutting is ectomycorrhizal (ECM) fungi, as they are associated with the roots of living trees. Retention forestry is a way of reducing logging impacts and enhancing biodiversity conservation. In-creasing the proportion of trees retained at harvest may improve ECM fungal diversity. 2. We investigated the potential for life-boating of ECM fungi through the harvesting phase in an experimental field study in a 190 years old Scots pine forest in northern Sweden. The experiment comprised four levels of tree retention – unlogged forest, plots with 60% or 30% of evenly distributed trees retained, and clear-cuts without retained trees. We sampled soils and determined identities, frequencies and relative abundances of ECM fungal species dur-ing three years following logging through the use of high-throughput sequencing of ampli-fied ITS2 markers. 3. We identified 151 ECM fungal species, with the five most abundant species accounting for 50% of the total ECM fungal amplicons. Three years after harvesting, the proportion of ECM sequences in the total amplicon pool had decreased proportionally to the extent of tree removal. In clear-cuts ECM fungal relative abundance had decreased by 95%, while ECM fungal species richness had declined by 75%, compared to unlogged plots. 4. Tree retention enabled maintenance of the most frequent ECM species, while more lowly abundant species were progressively lost at random with increasing level of tree removal. Five of the most frequent ECM fungal species remained present after clear-cutting, probably associated with pine seedlings. 5. Synthesis and applications. Tree retention can moderate short-term and potentially also long-term logging impacts on ectomycorrhizal (ECM) fungi. Local ECM fungal diversity is preserved in proportion to the amount of retained trees. Abundant species may be largely maintained, even by low levels of tree retention and on naturally established seedlings. However, conservation of more infrequent species requires higher levels of tree retention, and our results suggest that around 75% of the ECM species are lost with the forest certifi-cation standard of 5% retention trees left at logging. 4-Feb-2019

1. 短轮伐期且结构简化的营林活动已对森林生物多样性造成显著负面影响。受皆伐作业不利影响的生物类群之一为外生菌根（ectomycorrhizal, ECM）真菌，因其与活树根系形成共生关联。保留营林法是降低采伐影响、提升生物多样性保护成效的有效途径，提高采伐时保留树木的比例可改善外生菌根真菌的多样性。
2. 我们在瑞典北部一片190年树龄的欧洲赤松林中开展野外田间试验，探究外生菌根真菌在采伐阶段得以留存的潜力。试验设置了4个树木保留梯度：未采伐的原始林、保留60%均匀分布树木的样地、保留30%均匀分布树木的样地，以及无保留树木的皆伐样地。我们在采伐后的三年内采集土壤样本，通过扩增ITS2标记的高通量测序技术，鉴定外生菌根真菌的物种组成、出现频率及相对丰度。
3. 本研究共鉴定出151种外生菌根真菌，其中丰度最高的5个物种占总外生菌根真菌扩增子序列的50%。采伐三年后，总扩增子库中外生菌根真菌序列的占比随树木移除比例呈正比下降。与未采伐样地相比，皆伐样地的外生菌根真菌相对丰度下降了95%，物种丰富度则降低了75%。
4. 保留树木可维持出现频率最高的外生菌根真菌物种，而随着树木移除比例提升，丰度较低的物种会逐渐随机消失。皆伐后仍有5种出现频率最高的外生菌根真菌物种存活，其可能与天然更新的赤松幼苗形成共生关联。
5. 综合与应用。保留营林法可缓解采伐活动对外生菌根真菌的短期乃至潜在长期影响。局地外生菌根真菌的多样性保留程度与保留树木的比例呈正比。即便仅保留少量树木，依托天然更新的幼苗，丰度较高的物种也可基本得以维持。但对于稀有种的保护，则需要更高比例的树木保留量；本研究结果显示，若按照森林认证标准在采伐时仅保留5%的树木，约75%的外生菌根真菌物种将会流失。2019年2月4日