ИСТИНА

By now, green infrastructure (GI) of megapolises is exposed to growing impact of various human activities. At the same time, GI patches, especially the largest ones, are widely considered as powerful tools to mitigate climate changes and flood risk, retain wildlife habitats, improve air quality etc. A selected set of quantitative vulnerability indicators has been estimated through QGIS, Fragstats, Conefor, Graphab, Guidos Toolbox operations: effective mesh size, closeness to optimum shape (circles), fragmentation, connectivity, buffer fencing. A strong trend to vulnerability increase has been revealed, according to 1990-2022 dynamics of GI and protected areas (PAs), particularly in Moscow and Saint-Petersburg. Moreover, GI dynamics of Saint-Petersburg may be assessed as less significant (-3.6% compared to -5.9% in Moscow), but more stable, while Moscow drastic changes have taken place in 1990s predominantly (by about 1.2 times of initial value). Besides, fragmentation of planned protected areas has significantly contributed in vulnerability increase, mostly in Saint-Petersburg where dynamic difference of fragmentation indicator has been estimated to be at 1.7 times higher than in already established PAs. The considerable prevalence of highly vulnerable PAs clusters in Moscow has been identified through the devised PAs classification. The most concerning transformations are related not only to some extremely fragile linear GI elements (river valleys), but also to Elk Island national park. As GI ability to provide ecosystem services is heavily depends on patches' size and compactness, the continuation of revealed trends will lead to forthcoming drop in the well-being of citizens.