Bacteria, fungi, and protist are important in driving nutrient cycling. The microbiological mechanism underlying vegetation restoration during different temperature and precipitation gradients remains unclear. To determine the relationship between microbes and nutrients, we examined the changes in soil bacterial, fungal, and protist diversity and community composition under two different temperatures in a plantation forest and shrubland as well as reference cropland in a karst region. Bacterial and protist diversity in the warm and low-altitude region of Guangxi (average temperature 20.9°C) was higher in cropland than in shrubland or plantation forest. By contrast, fungal richness was lower in cropland than in shrubland. A co-occurrence network revealed higher numbers of correlated links among the bacterial, fungal, and protist taxa in the cool and high-altitude region of Guizhou (average temperature 14.6°C) than in the warm and low-altitude region of Guangxi. Stronger interactions were observed among microbial taxa under cropland than in vegetation restoration. The protist groups Cercozoa and Lobosa showed the highest numbers of links with the bacterial phyla Acidobacteria and Proteobacteria and with the fungal phylum Ascomycota. The numbers of Proteobacteria, Ascomycota, and Cercozoa were most correlated with soil nutrient levels of carbon, nitrogen, and phosphorus. Overall, microbial interactions were higher at low temperatures than at high temperatures, consequently intensifying the predation of bacteria and fungi by protists at a low-temperature level. Furthermore, Proteobacteria, Ascomycota, and Cercozoa were the keystone taxa linked to nutrient availability; hence, effective monitoring of these dominant groups may be beneficial for increasing nutrient accumulation during vegetation restoration.

中文翻译：

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喀斯特生态系统跨气候梯度植被恢复的微生物机制

细菌、真菌和原生生物在驱动营养循环方面很重要。不同温度和降水梯度下植被恢复的微生物机制仍不清楚。为了确定微生物和养分之间的关​​系，我们检查了喀斯特地区人工林和灌木丛以及参考农田在两种不同温度下土壤细菌、真菌和原生生物多样性和群落组成的变化。广西暖低海拔地区（平均气温20.9℃）的细菌和原生生物多样性，农田高于灌丛或人工林。相比之下，农田的真菌丰富度低于灌丛。共现网络揭示了细菌、真菌、贵州凉爽高海拔地区（平均气温14.6℃）的原生生物类群高于广西温暖低海拔地区。在农田下的微生物类群之间观察到比在植被恢复中更强的相互作用。原生生物群 Cercozoa 和 Lobosa 与细菌门酸杆菌门和变形杆菌门以及真菌门子囊菌门的联系数量最多。Proteobacteria、Ascomycota 和 Cercozoa 的数量与土壤中碳、氮和磷的养分水平最相关。总体而言，低温下的微生物相互作用高于高温下，因此在低温水平上加强了原生生物对细菌和真菌的捕食。此外，变形菌门、子囊菌门、Cercozoa 和 Cercozoa 是与养分可用性相关的关键类群；因此，有效监测这些优势群体可能有利于在植被恢复过程中增加养分积累。