Changes of woodland plant communities during the period 1959-2016 on the permanent study plot in the compartment 319 of the Bialowieza National Park

Abstract

The long−term changes of vegetation cover at the level of woodland community taking place between 1959 and 2016 on the permanent study plot located in the compartment 319 of Białowieża National Park are discussed. In 1959 two distinctive woodland community types occurring on sample plot were distinguished: subboreal mixed pine−oak forest (Serratulo−Pinetum) and hornbeam−lime forest (Tilio−Carpinetum). The phytosociological investigations, carried out almost 60 years later, revealed that in case of both communities, significant, directional changes of their floristic composition took place. Particularly high rate of change occurred in case of the phytocoenosis representing the Serratulo−Pinetum community. In 1959 it contained a full set of characteristic plant species. During the study period, this community type representing the Vaccinio−Piceetea class, was replaced by the initial form of lime−hornbeam forest belonging to the Querco−Fagetea class. Also, in case of the previous Tilio−Carpinetum association, the significant changes in the floristic composition occurred, although not as large as in case of Serratulo−Pinetum community. 60 years ago this community type contained several plant species typical for thermophilous oak forests. Nowadays, it represents a typical form of lime−hornbeam association. The changes in both community types were mainly related to the strong expansion of lime and hornbeam, which took place during the study period and involved the whole study plot. As a result, the vegetation occurring on the study plot is much more homogenous now than it was ca. 60 years ago. The maintenance of Serratulo−Pinetum phytocoenoses distinguished by a high floristic diversity calls for active protective measures in all cases where such measures are allowed and where this community type can potentially develop