The share of xerothermic species in vascular flora of the city of Lublin (Poland)

The purpose of this study is to present the distribution and characteristics of xerothermic flora located within Lublin (51o08’-51o18’N and 22o27’-22o41E). The data on this flora have been derived from the literature and herbarium collections as well as they were collected during field research conducted in 2002-2009. Family affiliation, life forms, geographical-historical groups, the degree of synanthropization of species and habitat, categories of threat are discussed in this paper. 107 xerothermic species belonging to 26 families and 70 genera were reported from the area of Lublin. The number constitutes 10% of the city’s flora. The most numerous are plants from the classes Festuco-Brometea (70 species), Trifolio-Geranietea sanguinei (21) and Rhamno-Prunetea (16). All extinct species (8) belong to the class Festuco-Brometea. The analysis of the spectrum of life forms indicates that the biggest share in the flora of Lublin was observed in the group of hemicryptophytes (57 species) and phanerophytes (14). The native species (103) dominate over the group of alien ones (4 species). The group of xerothermic plants comprises 21 legally protected and endangered species. Xerothermic plants exhibit a mosaic distribution in the area of Lublin. The frequency (measured as the presence of a species in a study unit, one ATPOL square) ranged from 1 to 44 species. Two main features of the analyzed area seemed to be responsible for species distribution: the value of the Real Hemeroby Index (RIH) and the history of the flora.