Factors determining changes in the flora of xerothermic habitats in Skierbieszów Landscape Park (SE Poland)
Skierbieszów Landscape Park was established in order to preserve the landscape of Działy Grabowieckie with beech, hornbeam woods, and xerothermic grasslands. The present study, compared with the results of the floristic studies conducted 30 years earlier, reveals that the xerothermic flora of described area is showing changes. The main goal of this paper was to investigate if changes in xerothermic flora of Skierbieszów Landscape Park (SE Poland) were caused by the cessation of use or by the influence of climatic changes. The flora of 15 slopes with dry grasslands was examined. The Ellenberg ecological indicator values were used to detect which habitat factor has changed the most. The greatest changes were noted in the value of substrate fertility N. But the changes of flora also demonstrated its statistically important dependences on temperature T and continentality K. The changes in xerothermic flora were mainly caused by succession. However, the increase in T and K indicators may have been caused by either their higher tolerance towards worsening light conditions or more favourable thermal conditions.