Abstract: The specifics and trends of ecosystem dynamics in the Buzuluk Pine Forest National Park are determined by a complex of climatic factors in the region. Their most important feature is the long-term cyclical nature of changes in key indicators. An analysis of the materials from the Borovoe Forestry Meteorological Station (MS) from 1905 to 2024 has made it possible to identify seven periods with a total duration of 57 years with reduced precipitation, and an equal number of periods with increased precipitation lasting 63 years. The noted trend of increased number of wet years has been observed since the second half of the last century. Changes in precipitation have affected the water availability of the territory and the state of its ecosystems.  During drought, the composition of ichthyofauna, amphibians, waterfowl and near-aquatic birds dramatically changed (at least 15 species disappeared, about 30 – sharply decreased). Semi-aquatic mammals populations also experienced changes. During the dry years, the structure of the dendrophilic ornithocomplex was significantly rebuilt – 26 species disappeared and 22 new species appeared in different communities, and the numbers of other species changed as well.