The impact of a large industrial city on the soil respiration in forest ecosystems

Abstract

The rate of soil respiration was measured in situ under native pine stands in a large industrial city (Yekaterinburg, Russia) and beyond it. The compared sites differed significantly in the two factors affecting soil respiration, i.e., in the degree of urbanization (including air pollution, changes in the microclimate, fragmentation of the biotopes, the appearance of introduced species, etc.) and in the character of recreation loads (primarily, trampling loads). The difference between soil respiration rates in the city and in the suburbs was significant; it reached its maximum in the summer, when the soil respiration in the city was 1.9–3.5 times lower than that in the suburbs. However, this difference was virtually absent in the spring and fall seasons. The impact of recreation loads on the soil respiration was relatively low; moreover, it could have both positive and negative signs, i.e., lead to the increase or decrease in the soil respirarion rate. The particular mechanisms explaining the influence of the considered factors on the rate of the CO2 emission from the soils are discussed.