Geoderma | 欧洲土地利用和气候介导的土壤细菌和真菌生物量变化及其驱动因素

题目：

Land-use- and climate-mediated variations in soil bacterial and fungal biomass across Europe and their driving factors

作者：

panelJosé A. Siles ^a*, Alfonso Vera ^a, Marta Díaz-López ^a, Carlos García ^a, Johan van den Hoogen ^b, Thomas W. Crowther ^b, Nico Eisenhauer ^c d, Carlos Guerra ^c e, Arwyn Jones ^f, Alberto Orgiazzi ^f, Manuel Delgado-Baquerizo ^g h, Felipe Bastida ^a

单位：

^a*Department of Soil and Water Conservation and Organic Waste Management, CEBAS-CSIC, Murcia, Spain

^bDepartment of Environmental Systems Science, Institute of Integrative Biology, ETH Zürich, Zurich, Switzerland

^cGerman Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany

^dInstitute of Biology, Leipzig University, Leipzig, Germany

^eInstitute of Biology, Martin Luther University Halle Wittenberg, Halle (Saale), Germany

^fEuropean Commission, Joint Research Centre, Ispra, Italy

^gLaboratorio de Biodiversidad y Funcionamiento Ecosistémico, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Sevilla, Spain

^hUnidad Asociada CSIC-UPO (BioFun), Universidad Pablo de Olavide, Sevilla, Spain

Highlights

•对欧洲各地的土壤细菌和真菌生物量的含量进行了定量。

•土地利用和气候共同控制土壤细菌和真菌的生物量。

•土壤农业用途缓冲了恶劣气候条件对细菌的影响。

•土壤质地、有机碳和有机氮是土壤微生物生物量的预测因子。

•土壤微生物生物量不受作物类型的影响。

Abstract

Fig. 1.Location, land-use type, and climate characterizing the 513 soils included in the study.

Fig. 2.Box plots comparing biomass (measured as fatty acid content) of soil bacteria, Gram-positive (GP) and Gram-negative (GN) bacteria, and Actinobacteria, as well as the Gram-positive/Gram-negative (GP/GN) and fungi/bacteria (F/B) ratios in croplands, grasslands, and forests under arid, temperate, and cold climates. P-values of two-way PERMANOVA for the factors land use (LU) and climate (C), and their interaction are shown at the top of each figure. Different lowercase letters above each box denote significant differences among climates within each land use, and different capital letters denote significant differences among land uses within each climate according to pairwise permutation tests. The boxes represent the interquartile range (IQR) between the first and third quartiles (25th and 75th percentiles, respectively), and the vertical line inside the box defines the median. Whiskers represent the lowest and highest values within 1.5 times the IQR from the first and third quartiles, respectively. Dots represent outliers.

Fig. 3.Random forest mean predictor importance (% increase in MSE (mean square error)) of the studied variables as predictors of biomass of soil bacteria, Gram-positive (GP) and Gram-negative (GN) bacteria, and Actinobacteria, as well as the Gram-positive/Gram-negative (GP/GN) and fungi/bacteria (F/B) ratios. Significance levels are shown at *P < 0.05 and **P ≤ 0.001. Predictors belonging to the same category were represented with the same color according to the legend. VE = variance explained (%). LU = land use. MAP = mean annual precipitation. MAT = mean annual temperature. AI = aridity index. NPP = net primary production. Sand, silt, and clay = soil sand, silt, and clay contents, respectively. BD = bulk density. EC = electrical conductivity. SOC = soil organic carbon. N and P = soil total nitrogen and phosphorus, respectively. K = extractable potassium.

Fig. 4. Dependences of soil bacterial and fungal biomass and the fungi/bacteria (F/B) ratio on selected environmental variables evaluated by regression analyses. The best model (linear or quadratic) fitting each regression is indicated at the top of each figure. Shaded areas represent 95 % confidence intervals for the regression line. R2 and P-values are shown for each regression analysis. Sand = soil sand content. SOC = soil organic carbon. N and P = soil total nitrogen and phosphorus, respectively. MAT = mean annual temperature.

Fig. 5.SEM (structural equation modeling) assessing the direct and indirect effects of selected factors on soil bacterial and fungal biomass and the fungi/bacteria (F/B) ratio. Numbers adjacent to arrows are standardized path coefficients and are indicative of the effect size. Only significant effects (P < 0.05) are indicated, and significance levels are shown at *P < 0.05 and **P ≤ 0.001. Continuous, dashed, and double-lined arrows indicate positive, negative, and mixed relationships, respectively. Underlined path coefficients indicate quadratic relationships. In the SEM on F/B, double-headed arrows represent covariance between variables. R² denotes the proportion of variance explained for every response variable by the model. The models were satisfactorily fitted to data, as suggested by non-significant χ² values and non-parametric bootstrap, and by values of RMSEA (root mean square error of approximation) and CIF (comparative fit index). MAT = mean annual temperature. NPP = net primary production. AI = aridity index. Sand = soil sand content. N and P = soil total nitrogen and phosphorus, respectively.