Wilhelm Roland C, Cardenas Erick, Maas Kendra R, Leung Hilary, McNeil Larisa, Berch Shannon, Chapman William, Hope Graeme, Kranabetter J M, Dubé Stephane, Busse Matt, Fleming Robert, Hazlett Paul, Webster Kara L, Morris David, Scott D Andrew, Mohn William W
Department of Microbiology &Immunology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.
British Columbia Ministry of Forests, Lands and Natural Resource Operations, Victoria, British Columbia, Canada.
ISME J. 2017 Nov;11(11):2552-2568. doi: 10.1038/ismej.2017.109. Epub 2017 Jul 28.
The growing demand for renewable, carbon-neutral materials and energy is leading to intensified forest land-use. The long-term ecological challenges associated with maintaining soil fertility in managed forests are not yet known, in part due to the complexity of soil microbial communities and the heterogeneity of forest soils. This study determined the long-term effects of timber harvesting, accompanied by varied organic matter (OM) removal, on bacterial and fungal soil populations in 11- to 17-year-old reforested coniferous plantations at 18 sites across North America. Analysis of highly replicated 16 S rRNA gene and ITS region pyrotag libraries and shotgun metagenomes demonstrated consistent changes in microbial communities in harvested plots that included the expansion of desiccation- and heat-tolerant organisms and decline in diversity of ectomycorrhizal fungi. However, the majority of taxa, including the most abundant and cosmopolitan groups, were unaffected by harvesting. Shifts in microbial populations that corresponded to increased temperature and soil dryness were moderated by OM retention, which also selected for sub-populations of fungal decomposers. Biogeographical differences in the distribution of taxa as well as local edaphic and environmental conditions produced substantial variation in the effects of harvesting. This extensive molecular-based investigation of forest soil advances our understanding of forest disturbance and lays the foundation for monitoring long-term impacts of timber harvesting.
对可再生、碳中和材料和能源日益增长的需求正导致林地利用的强化。与维持人工林中土壤肥力相关的长期生态挑战尚不清楚，部分原因是土壤微生物群落的复杂性和森林土壤的异质性。本研究确定了木材采伐（伴随不同程度的有机质去除）对北美18个地点11至17年生重新造林的针叶人工林中细菌和真菌土壤种群的长期影响。对高度重复的16S rRNA基因和ITS区域焦磷酸测序文库以及鸟枪法宏基因组的分析表明，采伐地块中的微生物群落发生了一致的变化，包括耐旱和耐热生物的扩张以及外生菌根真菌多样性的下降。然而，大多数分类群，包括最丰富和分布最广的类群，不受采伐影响。与温度升高和土壤干燥相关的微生物种群变化通过有机质保留得到缓解，有机质保留还选择了真菌分解者的亚种群。分类群分布的生物地理差异以及当地土壤和环境条件导致采伐影响存在很大差异。这项基于分子的对森林土壤的广泛调查增进了我们对森林干扰的理解，并为监测木材采伐的长期影响奠定了基础。
