土壤微生物网络复杂性预测黄土高原造林恢复生态系统多功能性

人类活动导致黄土高原土地退化和生物多样性丧失,进而降低了生态系统功能。人工造林是该区域退化土地恢复的重要措施。现有的生态修复研究通常侧重于微生物群落物种多样性的恢复对单一生态系统功能的影响,而忽略了微生物间存在的相互作用与生态系统多功能性(Ecosystem multifunctionality, EMF)的关系。为探究造林恢复过程中土壤微生物多样性和网络复杂性与EMF的关系,本研究采用时空代换法(space-time substitution method),沿50年造林恢复时间序列,分析了黄土高原地区造林恢复对土壤微生物群落多样性、土壤微生物网络复杂性以及与土壤养分循环相关的10个生态系统功能指标的影响,明确了土壤微生物群落特征与EMF的关系。结果表明,随造林恢复时间序列的增加,土壤微生物群落的综合多样性、网络复杂性和EMF均呈现出显著增加后下降的趋势(P<0.05),其中土壤微生物综合多样性和网络复杂性在第8年达到最高值,EMF在第20年达到最大值。在未控制土壤环境因素时,细菌和古菌多样性与EMF无显著相关性,真菌多样性与EMF呈显著正相关(P<0.001);土壤微生...

Soil microbial network complexity predicts the multifunctionality of afforestation restoration ecosystems on the Loess Plateau

Human activities have induced land degradation, loss of biodiversity, and the decline of the functions and services of ecosystems on the Loess Plateau. Vegetation restoration is an effective way to improve degraded ecosystems, and afforestation is an important measure to restore degraded land. Existing studies on ecological restoration have typically focused on the relationship between species diversity of microbial community and a single ecosystem function, neglecting the relationships between the interactions among microbial communities and ecosystem multifunctionality (EMF). In order to investigate the relationships of soil microbial biodiversity and the complexity of microbial networks with EMF in afforestation restoration, in this study, we used the space-time substitution method to investigate the effects of afforestation restoration on soil microbial diversity, soil microbial network complexity, and 10 variables of ecosystem function related to soil nutrient cycling and plant productivity along a 50-year afforestation chronosequence, with an aim to the relationships between the soil microbial community characteristics and EMF. The results indicated that microbial multi-diversity and network complexity of the soil microbial community increased significantly with the increase of time series of afforestation restoration, reaching a peak in the eighth year, and then decreased (P<0.05); EMF showed a trend of increasing and then decreasing, reaching a maximum in the twentieth year (P<0.05). With soil environmental factors not controlled, bacterial and archaeal diversity was not significantly correlated with EMF, while fungal diversity was significantly positively correlated with EMF (P<0.001). Both the soil microbial multi-diversity and network complexity showed significant positive correlations with EMF (P<0.001), with the soil microbial network complexity explaining more about EMF than microbial multi-diversity. Although the multi-diversity and network complexity of soil microorganisms explained less about EMF after controlling the effect of soil factors by partial least squares regression analysis (P<0.001), the microbial network complexity explained more about EMF than microbial multi-diversity. Furthermore, structural equation model (SEM) showed that soil microbial diversity had an indirect effect on EMF in afforested restoration sites through soil microbial network complexity. In summary, the microbial network complexity was a more effective predictor of EMF than soil microbial multi-diversity. Soil microbial multi-diversity positively influenced EMF in an indirect manner, mainly by contributing to network complexity. Our study revealed the relationship between microbial community characteristics and EMF in afforestation restoration ecosystems, providing a theoretical basis for improving the restoration of degraded restoration ecosystem functions.