The strength of the interaction is quantitatively established between nature-resource potentials in 14 provincial ecosystems of Ukraine, the latter being the equivalents of physic-geographical provinces (krais) of Ukraine. Nature-resource potential that covers mineral, water, land, forest, fauna, and natural recreation resources is regarded as one of the most essential characteristics of the field of ecosystems’ influence (effect). It is asserted that the strength of the effect of nature-resource potential of the ecosystem, or the bio-center, or the eco-region is the result of interaction between its central place and the surrounding area (periphery). The bigger the core (central place) and the less the distance to the neighboring core (other place of the ecosystem) with its own mass, the stronger it will affect the surround. The above strength is calculated according to the developed gravity methods. The value of the potential of nature resources in ecosystems in 2015-2021 prices represents the “body mass”, and the distances between the provinces are established to be those between their geometrical centers. The closest interaction is found to exist between nature-resource potentials of the Dniester-Dnieper and the Prychornomorskyy, as well as between the Donetsk and the Zadonetsko-Donskyy, the Left- Bank-Dnieper-Pryazovskyy and the Donetsk, the Left-Bank-Dnieper and the East-Ukrainian, and the Podilsko-Prydniprovskyy and the Dniester-Dnieper provincial ecosystems. The least strength of interaction between nature-resource potentials is observed between the Ukrainian Carpathians and the Crimean Mountains, the West-Ukrainian and the Crimean Mountains, the Polissia and the Crimean Mountains, the Zadonetsko-Donskyy and the Crimean Mountains, the Ukrainian Carpathians and the Prychornomorsko-Pryazovskyy provincial ecosystems.