College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing 100193, China; Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing 100193, China; Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2020 Dec 15;748:142381. doi: 10.1016/j.scitotenv.2020.142381. Epub 2020 Sep 16.
Extensive, progressive rock emergence causes localized variations in soil biogeochemical and microbial properties that may influence the capacity for the regeneration of degraded karst ecosystems. It is likely that karst ecosystem recovery relies on the persistence of soil functions at the microbial scale, and we aimed to explored the role of interactions between soil bacterial taxa and identify keystone species that deliver key biogeochemical functions, i.e. carbon (C) and nutrient (nitrogen, N and phosphorus, P) cycling. We applied high-throughput sequencing and phylogenetic molecular ecological network approaches to topsoils sampled at rock-soil interfaces and adjacent bulk soil along an established gradient of land-use intensity in the Chinese Karst Critical Zone Observatory. Bacterial α-diversity was greater under increased perturbation and at the rock-soil interface compared to bulk soils under intensive cultivation. However, bacterial ecological networks were less intricate and connected fewer keystone taxa as human disturbance increased and at the rock-soil interface. Co-occurrence within the bacterial community in natural primary forest soils was 13% larger than cultivated soils. The relative abundances of keystone taxa Acidobacteria, Bacteroidetes and Chloroflexi increased with land-use intensity, while Proteobacteria, Actinobacteria and Verrucomicrobia decreased by up to 6%. In general, Bacteroidetes, Verrucomicrobia and Chlorobi were related to C-cycling, Proteobacteria, Actinobacteria and Chloroflexi were related to N-cycling, and Actinobacteria and Nitrospirae were related to both N- and P-cycling. Proteobacteria and Chlorobi affected C-cycling and multiple functionality indexes in the abandoned land. We conclude that increasing land-use intensity changed the soil bacterial community structure and decreased bacterial interactions. However, increases in α-diversity at the rock-soil interface in cultivated soils indicated that major soil functions related to biogeochemical cycling were maintained within keystone taxa in this microenvironment. Our study provides foundations to test the success of different regeneration practices in restoring soil microbial diversity and the multifunctionality of karst ecosystems.
广泛而渐进的岩石出现导致土壤生物地球化学和微生物特性的局部变化，这可能影响退化喀斯特生态系统的再生能力。喀斯特生态系统的恢复很可能依赖于微生物尺度上土壤功能的持久性，我们旨在探索土壤细菌分类群之间的相互作用的作用，并确定提供关键生物地球化学功能的关键种，即碳 (C) 和养分（氮、N 和磷、P）循环。我们应用高通量测序和系统发育分子生态网络方法，对中国喀斯特关键带观测站在土地利用强度建立的梯度上，从岩石-土壤界面和相邻的大块土壤中采集的表土进行采样。与集约化种植下的大块土壤相比，在增加的干扰和岩石-土壤界面下，细菌 α 多样性更大。然而，随着人为干扰的增加和岩石-土壤界面的增加，细菌生态网络变得不那么复杂，连接的关键种也更少。在自然原始森林土壤中，细菌群落内的共现率比集约化种植土壤大 13%。在土地利用强度增加的情况下，酸杆菌门、拟杆菌门和绿屈挠菌门的相对丰度增加，而变形菌门、放线菌门和疣微菌门减少了多达 6%。一般来说，拟杆菌门、疣微菌门和绿菌门与 C 循环有关，变形菌门、放线菌门和绿屈挠菌门与 N 循环有关，放线菌门和硝化螺旋菌门与 N 和 P 循环有关。变形菌门和绿菌门影响废弃土地的 C 循环和多种功能指标。我们得出结论，增加土地利用强度改变了土壤细菌群落结构并减少了细菌相互作用。然而，在集约化种植土壤的岩石-土壤界面上，α 多样性的增加表明，与生物地球化学循环有关的主要土壤功能在这个微环境中通过关键种得以维持。我们的研究为检验不同再生实践在恢复土壤微生物多样性和喀斯特生态系统多功能性方面的成功提供了基础。
