Mundra Sunil, Kauserud Håvard, Økland Tonje, Nordbakken Jørn-Frode, Ransedokken Yngvild, Kjønaas O Janne
Section for Genetics and Evolutionary Biology (EvoGene), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, Oslo, NO-0316, Norway.
Department of Biology, College of Science, United Arab Emirates University, PO Box 15551, Al-Ain, Abu-Dhabi, United Arab Emirates.
New Phytol. 2022 Jun;234(6):2073-2087. doi: 10.1111/nph.18109. Epub 2022 Apr 10.
The replacement of native birch with Norway spruce has been initiated in Norway to increase long-term carbon storage in forests. However, there is limited knowledge on the impacts that aboveground changes will have on the belowground microbiota. We examined which effects a tree species shift from birch to spruce stands has on belowground microbial communities, soil fungal biomass and relationships with vegetation biomass and soil organic carbon (SOC). Replacement of birch with spruce negatively influenced soil bacterial and fungal richness and strongly altered microbial community composition in the forest floor layer, most strikingly for fungi. Tree species-mediated variation in soil properties was a major factor explaining variation in bacterial communities. For fungi, both soil chemistry and understorey vegetation were important community structuring factors, particularly for ectomycorrhizal fungi. The relative abundance of ectomycorrhizal fungi and the ectomycorrhizal : saprotrophic fungal ratio were higher in spruce compared to birch stands, particularly in the deeper mineral soil layers, and vice versa for saprotrophs. The positive relationship between ergosterol (fungal biomass) and SOC stock in the forest floor layer suggests higher carbon sequestration potential in spruce forest soil, alternatively, that the larger carbon stock leads to an increase in soil fungal biomass.
挪威已开始用挪威云杉取代原生桦树，以增加森林的长期碳储存。然而，关于地上变化对地下微生物群的影响，我们了解的还很有限。我们研究了从桦树到云杉林分的树种转变对地下微生物群落、土壤真菌生物量以及与植被生物量和土壤有机碳（SOC）关系的影响。用云杉取代桦树对土壤细菌和真菌丰富度产生了负面影响，并强烈改变了森林地表层的微生物群落组成，对真菌的影响最为显著。树种介导的土壤性质变化是解释细菌群落变化的主要因素。对于真菌而言，土壤化学性质和林下植被都是重要的群落结构因素，对外生菌根真菌尤其如此。与桦树林相比，云杉林中的外生菌根真菌相对丰度和外生菌根真菌与腐生真菌的比例更高，特别是在较深的矿质土壤层，腐生真菌的情况则相反。森林地表层中麦角固醇（真菌生物量）与SOC储量之间的正相关关系表明，云杉林土壤具有更高的碳固存潜力，或者说，更大的碳储量导致了土壤真菌生物量的增加。
