Papatheodorou Effimia M, Papakostas Spiros, Stamou George P
Department of Ecology, School of Biology, AUTH, 54124 Thessaloniki, Greece.
Department of Science and Technology, School of Science and Technology, University Center of International Programmes of Studies, International Hellenic University, 57001 Thessaloniki, Greece.
Microorganisms. 2023 Mar 19;11(3):790. doi: 10.3390/microorganisms11030790.
Fires are common in Mediterranean soils and constitute an important driver of their evolution. Although fire effects on vegetation dynamics are widely studied, their influence on the assembly rules of soil prokaryotes in a small-scale environment has attracted limited attention. In the present study, we reanalyzed the data from Aponte et al. (2022) to test whether the direct and/or indirect effects of fire are reflected in the network of relationships among soil prokaryotes in a Chilean sclerophyllous ecosystem. We focused on bacterial (genus and species level) co-occurrence patterns in the rhizospheres and bulk soils in burned and unburned plots. Four soils were considered: bulk-burnt (BB), bulk-unburnt (BU), rhizosphere-burnt (RB), and rhizosphere-unburnt (RU). The largest differences in network parameters were recorded between RU and BB soils, while RB and BU networks exhibited similar values. The network in the BB soil was the most compact and centralized, while the RU network was the least connected, with no central nodes. The robustness of bacterial communities was enhanced in burnt soils, but this was more pronounced in BB soil. The mechanisms mainly responsible for bacterial community structure were stochastic in all soils, whether burnt or unburnt; however, communities in RB were much more stochastic than in RU.
火灾在地中海地区的土壤中很常见，是其演变的一个重要驱动因素。尽管火灾对植被动态的影响已得到广泛研究，但在小规模环境中，火灾对土壤原核生物组装规则的影响却很少受到关注。在本研究中，我们重新分析了阿庞特等人（2022年）的数据，以测试火灾的直接和/或间接影响是否反映在智利硬叶生态系统中土壤原核生物之间的关系网络中。我们重点关注了火烧地块和未火烧地块根际土壤和大块土壤中细菌（属和种水平）的共现模式。研究考虑了四种土壤：大块火烧土（BB）、大块未火烧土（BU）、根际火烧土（RB）和根际未火烧土（RU）。在RU和BB土壤之间记录到网络参数的最大差异，而RB和BU网络表现出相似的值。BB土壤中的网络最紧凑且集中，而RU网络的连通性最差，没有中心节点。火烧土壤中细菌群落的稳健性增强，但在BB土壤中更为明显。无论火烧与否，所有土壤中决定细菌群落结构的主要机制都是随机的；然而，RB中的群落比RU中的群落随机性要强得多。
