Landscape metrics as a tool for the assessing spatial structure sustainability of green areas of the cities of Braslav and Baranovichi (Belarus)

The creation of a sustainable green areas system of cities, as one of the means of developing a comfortable urban environment, represents a pressing issue in the context of rapid urbanization. This article proposes one possible approach to addressing this issue—the use of landscape metrics as a fundamental tool for assessing the structural sustainability of green areas systems, using the cities of Braslav and Baranovichi as case studies. These cities differ in their natural conditions, size, and functional characteristics. Assessment and comparison was carried out according to three types of parameters: area (Mean Patch Area (AREA_MN), Largest Patch Index (LPI)); shape (Perimeter-Area Ratio Distribution (PARA_MN), Mean Patch Shape Index (SHAPE_MN)); aggregation (Patch Density (PD), Aggregation Index (AI), Splitting Index (SPLIT) and Effective Mesh Size (MESH)). The principal component analysis was applied for integrated characteristics and derivations to obtain computational scores indicating the degree of sustainability of urban green areas systems. The calculation results showed that the tendencies of green areas systems development in both cities are similar: decreasing area along with increasing fragmentation and splitting. The green areas system is characterized by unstable dynamics, with alternation of both positive and negative periods. The dynamics of the complex score is more unstable in Braslav, with frequent fluctuations from positive to negative condition (the best condition is indicated in 2017: 3.42 points; the worst condition is indicated in 2018: -2.40 points). Meanwhile, in Baranovichi city the variations were more gradual and a stable improvement has taken place in recent years (the best condition is registered in 2017: 3.63 points; the worst condition is registered in 2020: -2.82 points). Furthermore, it is also discovered that although the area is reducing, the improvement of such characteristics as aggregation, shape of patches, reduction of fragmentation and preservation of large patches allows maintaining the sustainability of green areas and allows providing guidelines towards optimization and options for improvement of its management framework.