Abstract The Araucaria forest is a sub-type of Atlantic Forest and it is critically endangered because of deforestation. Despite significant researchers’ attention, little is known about the microbial and functional soil diversity of this ecosystem. Our aim was to assess structural diversity (phospholipid fatty acid; PLFA), functional diversity (Biolog ecoplates) and physicochemical soil properties to identify which indicators are the most sensitive to alterations in the Araucaria ecosystems. Soils of three different areas (disturbed, reforested, and native Araucaria forest soils), in two parks of Southeast Brazil, were collected in contrasting seasons (dry and rainy). Principal components analysis (PCA) showed that fatty acid profiles, Biolog and physicochemical properties in Araucaria forest soils were more dissimilar between the different park geographic locations than by forest disturbance levels. However, discriminant analysis identified several variables with greater power to discriminate among forest disturbance levels (native, disturbed, and reforested) within each season. Reforested soils were lower in pH, Al+3, and base cation content compared to disturbed and native soils. Soils disturbed by recreational and understory deforestation were sandier in texture and elevated in P compared to native and deforested soils. Native soil microbial communities utilized certain Biolog substrates to a greater extent, depending on season, compared to communities of disturbed and reforested soils. The best discriminating variable among native, disturbed, and reforested soils for both seasons was γ-hydroxybutyric acid consumption, which was positively related to native, and negatively correlated to disturbed and reforested soils. Thus, γ-hydroxybutyric acid consumption may be a useful indicator to monitor the recovery of reforested and disturbed Araucaria soils in reference to its native state.

中文翻译：

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土壤理化和生物特征作为南洋杉森林干扰水平的指标

摘要 南洋杉林是大西洋森林的一个亚型，因森林砍伐而濒临灭绝。尽管研究人员非常关注，但对该生态系统的微生物和功能性土壤多样性知之甚少。我们的目标是评估结构多样性（磷脂脂肪酸；PLFA）、功能多样性（Biolog 生态板）和土壤物理化学特性，以确定哪些指标对南洋杉生态系统的变化最敏感。在巴西东南部的两个公园中，三个不同地区的土壤（受干扰的、重新造林的和本地南洋杉森林土壤）的土壤是在对比季节（干燥和雨季）收集的。主成分分析 (PCA) 表明脂肪酸谱，南洋杉森林土壤的生物和理化特性在不同公园地理位置之间的差异比森林干扰水平更大。然而，判别分析确定了几个变量，这些变量在每个季节内区分森林干扰水平（原生、干扰和重新造林）的能力更强。与扰动土壤和原生土壤相比，重新造林土壤的 pH、Al+3 和碱性阳离子含量较低。与原生土壤和森林砍伐的土壤相比，受到休闲和林下森林砍伐影响的土壤质地更沙，磷含量更高。与受干扰和重新造林的土壤群落相比，本地土壤微生物群落在更大程度上利用某些 Biolog 基质，具体取决于季节。原生、受干扰、和重新造林土壤两个季节的γ-羟基丁酸消耗量与原生土壤呈正相关，与扰动和重新造林土壤呈负相关。因此，γ-羟基丁酸的消耗量可能是监测重新造林和受干扰的南洋杉土壤相对于其自然状态的恢复的有用指标。