The composition and functioning of soil bacterial communities, as well as their responses to multiple perturbations, are not well understood in the terrestrial ecosystems. Our study focuses on the bacterial community of erosive and poorly developed soils (Haplic Leptosols) in Mediterranean rangelands of Extremadura (W Spain) with different grazing intensities. Leptosols from similar natural conditions were selected and sampled at two depths to determine the soil properties as well as the structure and activity of bacterial communities. As grazing intensified, the soil C and N content increased, as did the number and diversity of bacteria, mainly of fast-growing lineages. , 6 and , , and increased their abundance along the grazing-intensity gradient. Firmicutes such as and from livestock microbiome also increased. In functional terms, the KEGG pathways enriched in the soils with moderate and high grazing intensity were ABC transporters, DNA repair and recombination proteins, the two-component system, and the degradation of xenobiotics. All of these proved to be related to stronger cell division and response mechanisms to environmental stressors such as drought, warming, toxic substances, and nutrient deprivation. Consequently, the bacterial community was affected by grazing, but appeared to adapt and counteract the effects of a high grazing intensity. Therefore, a clearly detrimental effect of grazing was not detected in the bacterial community of the soils studied.

中文翻译：

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牲畜放牧下地中海轻土细菌群落的组成和功能分析

陆地生态系统中土壤细菌群落的组成和功能以及它们对多种扰动的反应尚不清楚。我们的研究重点是埃斯特雷马杜拉（西班牙西部）地中海牧场不同放牧强度的侵蚀性和发育不良的土壤（Haplic Leptosols）的细菌群落。选择来自相似自然条件的稀土并在两个深度采样，以确定土壤特性以及细菌群落的结构和活性。随着放牧的加强，土壤碳和氮含量增加，细菌的数量和多样性也增加，主要是快速生长的谱系。 、 6 和 , , 并沿着放牧强度梯度增加它们的丰度。来自家畜微生物组的厚壁菌门也有所增加。从功能角度来看，中高放牧强度土壤中富集的KEGG途径有ABC转运蛋白、DNA修复和重组蛋白、双组分系统和外源物质降解。所有这些都被证明与更强的细胞分裂和对干旱、变暖、有毒物质和营养缺乏等环境压力的反应机制有关。因此，细菌群落受到放牧的影响，但似乎能够适应并抵消高放牧强度的影响。因此，在所研究的土壤细菌群落中没有检测到放牧的明显有害影响。