Original paper

Distribution history of xerothermic plant species under increasing anthropopression in Polish Pomerania

Prajs, Bozena

Abstract

In Polish Pomerania, xerothermic plants characteristically occur in insular, extrazonal habitats, often near the borders or at least outside the core area of their distribution range. The microclimate and soil of these sites resemble those of steppes and forest steppes. This study reconstructs the distribution history of 104 plant species found in the xerothermic swards of Polish Pomerania, with a focus on human impacts. The data were drawn from a number of historical works on Pomerania's xerothermic flora, and distribution maps with a 5 × 5 km mesh were generated using the RAR (Regional Atlas of Plants) software with a cartogram method. The xerothermic species in the study can be divided into three groups according to their response to human impacts: 1. species with diminishing ranges, 2. species with more or less stable ranges, 3. species that spread synanthropically. Polish Pomerania's numerous forests and lakes limit the expansion of steppe species. However, a warming of the regional climate could lead to the expansion especially of Pontic and Mediterranean species.

Keywords

northwest polandmicroclimateanthropogenic influence