Stursová Martina, Snajdr Jaroslav, Cajthaml Tomáš, Bárta Jiří, Santrůčková Hana, Baldrian Petr
Institute of Microbiology of the ASCR, v.v.i., Vídeňská 1083, Praha 4, Czech Republic.
Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
ISME J. 2014 Sep;8(9):1920-31. doi: 10.1038/ismej.2014.37. Epub 2014 Mar 27.
Coniferous forests cover extensive areas of the boreal and temperate zones. Owing to their primary production and C storage, they have an important role in the global carbon balance. Forest disturbances such as forest fires, windthrows or insect pest outbreaks have a substantial effect on the functioning of these ecosystems. Recent decades have seen an increase in the areas affected by disturbances in both North America and Europe, with indications that this increase is due to both local human activity and global climate change. Here we examine the structural and functional response of the litter and soil microbial community in a Picea abies forest to tree dieback following an invasion of the bark beetle Ips typographus, with a specific focus on the fungal community. The insect-induced disturbance rapidly and profoundly changed vegetation and nutrient availability by killing spruce trees so that the readily available root exudates were replaced by more recalcitrant, polymeric plant biomass components. Owing to the dramatic decrease in photosynthesis, the rate of decomposition processes in the ecosystem decreased as soon as the one-time litter input had been processed. The fungal community showed profound changes, including a decrease in biomass (2.5-fold in the litter and 12-fold in the soil) together with the disappearance of fungi symbiotic with tree roots and a relative increase in saprotrophic taxa. Within the latter group, successive changes reflected the changing availability of needle litter and woody debris. Bacterial biomass appeared to be either unaffected or increased after the disturbance, resulting in a substantial increase in the bacterial/fungal biomass ratio.
针叶林覆盖了北半球寒温带和温带的大片区域。由于其初级生产力和碳储存能力，它们在全球碳平衡中发挥着重要作用。森林火灾、风倒或虫害爆发等森林干扰对这些生态系统的功能有重大影响。近几十年来，北美和欧洲受干扰影响的面积都有所增加，有迹象表明这种增加是由当地人类活动和全球气候变化共同导致的。在这里，我们研究了云杉林中凋落物和土壤微生物群落对树皮甲虫 Ips typographus 入侵后树木死亡的结构和功能响应，特别关注真菌群落。昆虫引发的干扰通过杀死云杉树迅速而深刻地改变了植被和养分有效性，使得易获得的根系分泌物被更难分解的聚合植物生物质成分所取代。由于光合作用急剧下降，一旦一次性的凋落物输入被处理，生态系统中的分解过程速率就会降低。真菌群落表现出深刻的变化，包括生物量减少（凋落物中减少 2.5 倍，土壤中减少 12 倍），同时与树根共生的真菌消失，腐生类群相对增加。在后者中，连续的变化反映了针叶凋落物和木质碎片可用性的变化。干扰后细菌生物量似乎未受影响或有所增加，导致细菌/真菌生物量比大幅增加。
