Monitoring and assessing anthropogenic influence on soil's health in urban forests: The case from Moscow City

Abstract

Urbanization dominates current land-use change with important environmental consequences worldwide. Urban green zones including parks and urban forests provide key functions and services for city dwellers. Most of the urban forests' functions, including biodiversity maintenance, supporting carbon and nitrogen cycles and climate mitigation are supported by soil. Therefore, urban forests' soil health and its vulnerability to anthropogenic influence need thorough investigation. In the chapter the anthropogenic influence on soil health was studied for the unique forest experimental station located in Moscow and exposed to urbanization for more than a century. Changes in soil physical (bulk density), chemical (nutrients' and heavy metals' concentrations and mobility), and biological features (amount of ammonifiers and soil nitrogen-fixing activity) resulted from continuous urbanization and anthropogenic load were studied. Urbanization effect on soil health and functions was examined through comparison of the recent soil features to the historical data obtained at the same experimental sites prior urbanization, whereas anthropogenic influence gradient was studied based on the proximity to the roads and residential blocks. Substantial anthropogenic influence on soil features, their time dynamics, spatial variability, and profile distribution was found. Urban forest soils' contamination with heavy metals was more than ten times higher compared to the non-urbanized counterparts. Concentration of heavy metals increased and nutrients' concentration decreased from the forest core to the boundary zones. Over-compaction of forest topsoil was observed in proximity to the pathway network. Negative changes in soil chemical and physical features resulted in substantial decline in soil health and depletion of important soil functions, like support of a nitrogen cycle. The observed negative trend in forest soil health, resulted from urbanization and anthropogenic pressure, highlights importance to develop strategies of sustainable urban development, integrating green zones into urban areas.