Establishing the ≪environmental framework≫ has a special significance for current conditions of Moldova where ≪key areas of sustainable development≫ should be recognized as the highest category in the land planning practices. The main idea for projecting and designing the environmental protection facilities is the need to restrict economic activities and protect (totally or partially) certain areas of geographic space for carrying out of some specific ecological functions. Such measures include (Dyakov & Doncheva, 2002): preservation (biodiversity conservation of standard and unique natural systems); regulation (maintenance of ecological balance); and recovery of certain types of natural resources. At the same time, it needs during organization of environmental protection facilities to take into considerations a general natural law that may be formulated (Hilmi, 1966) as “a separate system functioning in an environment with organization level below than the level of the given system is doomed to be “dissolved” in that environment”. Theory of the island biogeography comprises similar statements that changes in character of island biota take place due to isolation and lead to floral and faunal depletion, increase of density of some species and of their ecological niches, to a gradual decrease of species diversity (effect of insularization). This circumstance has particular importance for Moldova with its’ extremely high degree of land transformation due to economic development history and the low percentage of Protected Areas. Meanwhile, rate of species extinction depends directly on sizes of a Protected Area. The smaller size of these areas and higher the degree of their isolation, the more intensively so-called “faunal collapse” becomes apparent (Dyakov & Doncheva, 2002). One of the ways to minimize effect of the “faunal collapse” is reduction of the isolation effect by decreasing the anthropogenic impacts upon surrounding landscapes, organization of ecological corridors and creation of buffer zones. An optimal buffer zone area may be calculated as (Sukhanov, 1993): [( ) ] 1 2 1 2 A = 1− Z −1 A − where “ Z ” is constant; “ 1 A ” and “ 2 A ” are squares of the Protected Area and its’ buffer zone respectively. When Z = 0.25, A2 is 2.16 times more than A1. If Protected Area has shape of a circle with a radius R1, the buffer zone should have a shape of the ring with its’ outer R2 = 1.78R1. If a Protected Area has the polygonal boundary, then the optimal value of its’ buffer zone is calculated using the coordinates of angles of the polygon that approximates boundary of the Protected Area (Sukhanov, 1993). The total calculated square of buffer zones of forest areas in the Republic of Moldova should take about 18% of the country. Combining the total forest area and total area of the buffer zones, we get an area equal to about 27% of the country surface, where some regulation of economic activities is necessary in order to provide the territory’s ability to carry out the environment-stabilizing functions. This is another evidence that optimization of natural-economic balance is necessary in order to maintain the environmental sustainability of the country through increasing the share of the environment-stabilizing areas. Besides, configurations of boundaries of Protected Areas are important and are to be taken into account. Theoretically, the optimal configuration is capable to ensure representativeness of natural systems, maintain biodiversity and necessary stability covering the least area. The most suitable shape is a circle, which, of all the geometric shapes of the same area, has the smallest perimeter. This reduces length of boundaries of protected areas and a number of points of contact with the adjacent natural and transformed landscapes. In addition, the circle shape minimizes the distance of moving within a territory that is important for migrations of various species (Sokolov et al., 1997). The above mentioned factors should be taken into account during formation of the environment-stabilizing network that would provide a higher nature conservational benefits on the background of deficit of areas, which may be withdrawn from economic circulation in order to maintain the ecological balance of the territory of Moldova.