We investigated: a) the hydrology of a small Sphagnum mire located in a transitional climate in Eastern Europe, and b) the relationships between the local climate and hydrology of the mire. We hypothesized that temperature is the most important factor determining water table changes in this type of peatland in an exceptional biogeographic setting. Research on the Linje mire revealed that the groundwater table was predominantly influenced by air temperature, which determines the rate of evapotranspiration, particularly in summer. Another important physical factor that significantly influences the variation in groundwater table of the mire is the permeability of the surface deposits. Moreover, the vegetation (especially Sphagnum) also has a modifying influence. Our study is the first of this kind in the young glacial area of Poland as well as in Eastern Europe. There is a need to improve precision of the study by installing automatic data loggers, as well as to intensify monitoring of the mire and its surroundings in order to obtain a better picture of the relationships between the mire and forest management in its vicinity. Furthermore, in the future we plan to extend the monitoring to hydrochemistry and microbial indicators (e.g. testate-amoebae and bacteria) to use the ecosystem approach in management of this valuable site.