Why are some plant species becoming extinct while others spreading?
The research was carried out in the Kraków-Częstochowa Jurassic Upland (Southern Poland). Two groups of plants were distinguished in the vascular flora of this area, each consisting of 32 species: probably extinct and invasive. All species were described in respect of 33 traits related to their morphology, anatomy, reproduction biology, phenology, chorology, taxonomy, habitat requirements, life strategy and response to human impact. The objective of this study is to answer the question which traits of plant species determine their extinction or spreading. To demonstrate statistically significant differences between invasive and extinct species, Pearson's chi-square test was applied. The statistically significant differences were found for 16 traits. The compared groups of plants differed the most in terms of stem height, human use, the degree of hemeroby, urbanity, the number of sites, types of plant communities in which they occur, the nitrogen content in the substrate and the life strategy. Statistically significant differences were also determined for the pollination method, anatomical structure of leaves, dicliny, the type and weight of a diaspore, duration of the flowering period, taxonomic affinity with a family and the soil moisture value. It has been found that invasive species are mostly medium-sized plants (0.5-2 m high), often cultivated by man, abundant on anthropogenic habitats; they are nitrophilous, mesophilic, self-pollinating and C-strategists. On the other hand, extinct species are up to 0.5 m high. They are not crop plants and occur mostly on natural and semi-natural habitats, on substrates with low content of nitrogen and they are CSR-strategists.