Urban soil respiration and its autotrophic and heterotrophic components compared to adjacent forest and cropland within the moscow megapolis

Urbanization is a key land-use change pathway, increasing urban population and resulting in abandonment of rural areas. Urbanization alters profoundly soil properties and functions, including soil respiration [90]. Soil respiration includes heterotrophic (microbial) and autotrophic (root) components. Both are driven by biotic and abiotic factors. Soil respiration and its components in urban ecosystems remain poorly known. In the present study, the spatial and temporal variability of total soil respiration (Rs) and its components were analyzed for different ecosystems included in the Moscow megalopolis area. In particular, highly impacted areas of urban green lawns were compared to arable lands and urban forest sites. Respiration fluxes were monitored during the whole vegetation period. An average Rs was significantly higher for the most disturbed sites, compared to more natural sites. For all the sites, Rh was the dominant component of soil respiration. We report the highest heterotrophic respiration ratio to microbial C (qCO2 = Rh/Cmic) for the lawn land use, followed by arable sites and forest sites, characterized by the lowest qCO2. An average Ra contributed to total Rs only to a minor extent (26%) and increased in all study sites along the season. Ra absolute values and contribution to Rs were similar for different land use types.