Dangerous simplification of ecosystems is a consequence of landscape destruction in highly populated areas in Ukraine. At the same time the chance of enlarging protected areas in these regions is limited. It may, however, be possible to maintain biodiversity in farming areas through a combination of nature conservation and agricultural production. This approach should aim to set up special preserved areas similar to natural ecosystems and more diverse than the surrounding countryside. Areas under irrigational, around fishery ponds, protective forest belts, meadows used for honey production, and anti-erosion plantations could be regarded as potential preserved areas. Threatened species in devastated localities are can be protected in these ecosystems. For example, in fishery areas of the central part of the Dnieper River and environs more than 100 species of vertebrates apart from fish are known to occur. Such ecosystems are not completely natural but could be biodiversity reservations in agricultural landscapes. These ecosystems, which replace natural ones, are particularly worthy of study and protection. They are, however, not yet protected by law. It is firstly necessary to categorize these semi-natural ecosystems and to establish their importance in maintaining biodiversity. Regulations about their status as preserved areas then should be agreed between users and the responsible state institution (perhaps initially as a landscape park or designated area). The country's bank of natural reserves could thus be markedly increased at no large cost. This research is supported by the Foundation of D.D. & K.T. MacArthur.