Kyiv green areas: assessment of the functioning efficiency and volumes of ecosystem services for erosion control

Abstract

The paper presents the assessment of the functional effectiveness and volumes of erosion-control ecosystem services (ES). Such an assessment is necessary because only a sus- tainable green space is able to provide its ESs to the fullest extent. One of the main functions of urban green areas is soil protection. Its effectiveness determines the volume of this ES – erosion control. The objective of this study was to assess the effectiveness of the soil-protection function and the volume of this ES. The identification was based on the use of models for estimating erosion-driven soil removal. For this purpose, according to natural and anthropogenic factors, we substantiated a set of functional-efficiency parameters, by which it is possible to quantify it. These parameters were included as attributes in the database of green areas of Kyiv. In the process of geoinformation modeling, the rates of erosive processes were determined. The efficiency was assessed by comparing the rates of naturally and antropogenically caused erosion and the process of soil formation. The source materials were vector sets of geodata about the relief, soils, and vegetation of the Kyiv territory. The sets were created based on the data about the natural base (landscapes) of the city, remote sensing data, and the field and laboratory studies. The assessment was conducted in 50 selected green areas of Kyiv. By analyzing the geodata, we estimated erosion rate in each of the areas, based on which the green areas were divided into categories according to effectiveness of the soil-protection function. In 14% of the studied green areas, the rate of erosion-caused loss of soil has been over 1 t/ ha/year, so the effectiveness of the soil-protection function in these areas was considered bearable, and the scope of ES provision was average. Another 4% of the green areas have been losing 0.5 to 1 t/ha/year, so the efficiency was near-optimal, and the amount of ES was above-average. In other territories, the erosion rate was insignificant, mainly due to the flat relief, soils with a light granulometric composition, as well as the use of lawn grass in decorating parks, garden squares, etc. In green areas where the erosion rates were the highest – over 2 t/ha/year – in addition to the relief-dependent factors, there were also higher values of the vegetation-cover factor, which can be attributed to a significant percentage of areas with open ground. The use of geoinformation modeling in the assessment of ES volumes is applicable to any green space, and allows one to measure the actual volume of ES, accounting for natural and anthro- pogenic erosion factors.