Calderón Kadiya, Philippot Laurent, Bizouard Florian, Breuil Marie-Christine, Bru David, Spor Aymé
Agroécologie, AgroSup Dijon, INRA, Université Bourgogne Franche-Comté, Dijon, France.
Departamento de Investigaciones Científicas y Tecnológicas Universidad de Sonora, Hermosillo, Mexico.
Front Microbiol. 2018 Nov 6;9:2721. doi: 10.3389/fmicb.2018.02721. eCollection 2018.
There is a growing interest of overcoming the uncertainty related to the cumulative impacts of multiple disturbances of different nature in all ecosystems. With global change leading to acute environmental disturbances, recent studies demonstrated a significant increase in the possible number of interactions between disturbances that can generate complex, non-additive effects on ecosystems functioning. However, how the chronology of disturbances can affect ecosystems functioning is unknown even though there is increasing evidence that community assembly history dictates ecosystems functioning. Here, we experimentally examined the importance of the disturbances chronology in modulating the resilience of soil microbial communities and N-cycle related functions. We studied the impact of 3-way combinations of global change related disturbances on total bacterial diversity and composition, on the abundance of N-cycle related guilds and on N-cycle related activities in soil microcosms. The model pulse disturbances, i.e., short-term ceasing disturbances studied were heat, freeze-thaw and anaerobic cycles. We determined that repeated disturbances of the same nature can either lead to the resilience or to shifts in N-cycle related functions concomitant with diversity loss. When considering disturbances of different nature, we demonstrated that the chronology of compounded disturbances impacting an ecosystem determines the aggregated impact on ecosystem properties and functions. Thus, after 3 weeks the impact of the 'anoxia/heat/freeze-thaw' sequence was almost two times stronger than that of the 'heat/anoxia/freeze-thaw' sequence. Finally, we showed that about 29% of the observed variance in ecosystem aggregated impact caused by series of disturbances could be attributed to changes in the microbial community composition measured by weighted UniFrac distances. This indicates that surveying changes in bacterial community composition can help predict the strength of the impact of compounded disturbances on N-related functions and properties.
人们越来越关注如何克服与所有生态系统中不同性质的多种干扰的累积影响相关的不确定性。随着全球变化导致严重的环境干扰，最近的研究表明，干扰之间可能的相互作用数量显著增加，这些干扰可能对生态系统功能产生复杂的、非相加性的影响。然而，尽管越来越多的证据表明群落组装历史决定了生态系统功能，但干扰的时间顺序如何影响生态系统功能仍不清楚。在这里，我们通过实验研究了干扰时间顺序在调节土壤微生物群落恢复力和氮循环相关功能方面的重要性。我们研究了与全球变化相关的干扰的三元组合对土壤微宇宙中总细菌多样性和组成、氮循环相关类群的丰度以及氮循环相关活动的影响。所研究的模型脉冲干扰，即短期停止干扰，是热、冻融和厌氧循环。我们确定，相同性质的重复干扰可能导致氮循环相关功能的恢复或转变，并伴随着多样性丧失。当考虑不同性质的干扰时，我们证明了影响生态系统的复合干扰的时间顺序决定了对生态系统特性和功能的综合影响。因此，3周后，“缺氧/热/冻融”序列的影响几乎是“热/缺氧/冻融”序列的两倍。最后，我们表明，由一系列干扰引起的生态系统综合影响中约29%的观测方差可归因于通过加权UniFrac距离测量的微生物群落组成的变化。这表明，调查细菌群落组成变化有助于预测复合干扰对氮相关功能和特性的影响强度。
