Floristic variation in communities of fallow lands of the Podlaski Przełom Bugu mesoregion depending on the time of removal of fields from cultivation

A study of fallow lands in the Podlaski Przełom Bugu (Podlasie Bug River Gorge) mesoregion was conducted over the period 2001–2004 in 77 villages belonging to 20 municipalities located in the Bug River valley along the stretch of the river from Terespol to Małkinia Górna. The aim of this study was to carry out a survey of vascular plants in fallow lands and to perform their multifaceted analysis. The study investigated quantitative and qualitative changes taking place in fallow vegetation with the passage of time from the abandonment of purposeful cultivation. Plant patches in 1–2-year, 3–6-year, 7–10-year and more than 10-year fallows were studied. Vascular plants of fallow lands within the study area comprise 442 species. 3–6-year fallows were richest in species (355). With increasing fallow age, the number of species decreased to 205 species in fallows older than 10 years. Hemicryptophytes dominated in plant communities of fallow lands. Therophytes were the co-dominant biological type in the youngest fallows. Chamaephytes and geophytes in all fellow age groups accounted for about 5%. Among vascular plants of fallow lands, native species dominated and their percentage increased with increasing fallow age, while at the same time the proportion of archeophytes decreased. With the increasing age of fallows, the proportion of species characteristic of forest communities also increased, whereas the percentage of segetal species simultaneously decreased. With the passage of time from the abandonment of cultivation, one can observe the evolution of plant cover of fallow fields from segetal communities towards less synanthropic communities