Floral diversity of plant communities in field balks

The aim of the research was to study the floristic richness of balks, i.e. uncultivated strips separating fields, and to research the dependence of plant communities there on habitat conditions and adjacent crops. The share of segetal species in those communities was also analysed. In the western part of the Siedlce Plateau 70 balks among intensively cultivated fields were examined in 2016–2018. The balks divided fields with corn, winter cereals and spring cereal mixtures. The research was conducted with the Braun-Blanquet method, with 110 phytosociological relevés results used as study material. The flora specified this way was analysed in terms of biological structure, forms of life, persistence, historical and geographical spectrum, species rarity and presence of invasive species. In addition, the interdependence between the species richness of balks and habitat conditions as well as the type of neighbouring crops was studied. Habitat conditions were established with the Ellenberg indicator values, based on indicative species and taking into account light, temperature, moisture, soil reaction and nitrogen content. The development and floristic diversity of balk plant communities as ecotone areas were largely influenced by a proximity of arable fields and habitat conditions, especially by soil moisture and the amount of nitrogen. Balk flora consisted of vascular plants with 161 species, mainly apophytes. Those were mostly perennial species, hemikryptophytes. Among the most common field weeds from the class of Stellarietea mediae, 25 species were identified in balks. There were 26 rare and endangered species and 14 species having the status of invasive taxa.