Microbial Indicators of Urban Soils and Their Role in the Assessment of Ecosystem Services: a Review

Abstract: An important element of the urban environment is soil, the balanced functioning of which largely depends on the soil microbiome. The state of the microbiome can be identified by different microbial indicators. However, there is still no answer to the question: which microbial indicators can most informatively reflect the functioning of urban soils and be useful in planning and landscaping urban areas? Databases eLibrar-y.ru, Web of Science, and Scopus were used to collect Russian and foreign papers published in the past 25 years on the study of the soil microbial properties in different cities of the world. It is revealed that the main attention in the study of urban soils is directed to the assessment of the microbial taxonomic structure, its gases’ production and enzymatic activities, the content of microbial biomass, its ecophysiological status, microbial functional diversity, cell morphology, and the presence of pathogenic and opportunistic microorganisms. The criteria of various microbial indicators (reproducibility, selectivity, cost, standardization, interpretation and understanding, recognition by the scientific community) are proposed to illustrate their acceptability and informative value for assessing the functions of urban soils and ecosystem services. The highest correspondence with such criteria was found for the soil microbial activity and the ecophysiological status, and the lowest belongs to the abundance of functional genes and “key groups” of microorganisms. The necessity of studying the relationship of the taxonomic diversity of the microbiome of urban soils with their main functions and the interpretation of experimental results in terms of ecosystem services is justified. © 2021, Pleiades Publishing, Ltd.