Gillespie Lauren M, Fromin Nathalie, Milcu Alexandru, Buatois Bruno, Pontoizeau Clovis, Hättenschwiler Stephan
Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), CNRS, UMR 5175, Université de Montpellier, Université Paul Valéry, EPHE, IRD, Montpellier, France.
Ecotron Européen de Montpellier, CNRS, UPS, 32980, Montferrier-sur-Lez, France.
Commun Biol. 2020 Jul 14;3(1):377. doi: 10.1038/s42003-020-1112-0.
Predicted increases in drought frequency and severity may change soil microbial functioning. Microbial resistance and recovery to drought depend on plant community characteristics, among other factors, yet how changes in plant diversity modify microbial drought responses is uncertain. Here, we assessed how repeated drying-rewetting cycles affect soil microbial functioning and whether tree species diversity modifies these effects with a microcosm experiment using soils from different European forests. Our results show that microbial aerobic respiration and denitrification decline under drought but are similar in single and mixed tree species forests. However, microbial communities from mixed forests resist drought better than those from mono-specific forests. This positive tree species mixture effect is robust across forests differing in environmental conditions and species composition. Our data show that mixed forests mitigate drought effects on soil microbial processes, suggesting greater stability of biogeochemical cycling in mixed forests should drought frequency increase in the future.
预计干旱频率和严重程度的增加可能会改变土壤微生物功能。微生物对干旱的抗性和恢复能力取决于植物群落特征等因素，然而植物多样性的变化如何改变微生物对干旱的反应尚不确定。在这里，我们通过一项微观实验，利用来自不同欧洲森林的土壤，评估了反复的干湿循环如何影响土壤微生物功能，以及树种多样性是否会改变这些影响。我们的结果表明，干旱条件下微生物的有氧呼吸和反硝化作用会下降，但在单一树种森林和混交林中相似。然而，混交林的微生物群落比单一树种森林的微生物群落更能抵抗干旱。这种积极的树种混合效应在环境条件和物种组成不同的森林中都很显著。我们的数据表明，混交林减轻了干旱对土壤微生物过程的影响，这表明如果未来干旱频率增加，混交林中生物地球化学循环的稳定性会更高。
