Zmiany składu gatunkowego i wskaźników struktury zbiorowisk roślinnych w latach 2001‑2018 na wybranych powierzchniach stałych w Kampinoskim Parku Narodowym = Changes of species composition and structural indices among plant communities in 2001‑2018 on selected permanent plots in Kampinos National Park

On the basis of 2001, 2007, 2012 and 2018 phytosociological records obtained from 52 permanent plots distributed across Poland’s Kampinos National Park, it proved possible to determine main directions of change in the ecological character of undergrowth. Reference to similarity of species composition on the plots between 2001 and 2018 allowed for the identification of Groups: A (occurring in boggy alder forest habitats, and comprising communities at different successional stages), B (coniferous and mixed-coniferous forests), C (oak-hornbeam forests and similar communities) and D (vegetation representing different dynamic stages of the succession from non-forest to forest communities). Irrespective of each plot’s unique history, the above Groups of plots could be characterised in line with specific sets of features subject to directional change during the period under analysis. Where Group A communities were concerned, a rise in the level of ground water and a decline in the content of organic carbon in soil were experienced, with the result that fen sedge species (Scheuchzerio-Caricetea) came to play a reduced role, even as there was a steadily-increasing role for species associated with communities flooded at least periodically (hence Potamogetonetea and Bidentetea). This was accompanied by a decrease in the number of shrub species and an increase in the number of bryophyte species. There were also increases in the proportions of geophytes and species associated with habitats more abundant in nitrogen. Group B communities were likewise subject to rising water tables, albeit changes not reflected directly in differing vegetation characteristics. The carbon: nitrogen ratio in soils here increased, as did numbers of species characteristic of undergrowth, as well as the bryophyte layer. Nevertheless, where undergrowth species were concerned, the role of those typical for open sandy grasslands (Koelerio-Corynephoretea) is seen to be declining, with this inter alia denoting increased shares of species either tolerant of shade or avoiding full illumination. There has also been a decline affecting hemicryptophytes, even as species associated with more nitrogen-rich habitats have come to account for greater shares. Where Group C communities encountered higher water levels, certain patches present in wetter habitats saw increases in the role played by species characteristic for class Bidentetea. The sorption capacities of soils here decreased, while values for the C: N ratio rose. Tree and shrub species came to be fewer in number as numbers of undergrowth species rose. There were also increases in the roles of species characterising moist verges (Galio-Urticenea), as well as geophytes. Group D communities likewise encountered rising groundwater levels, but did not seem to experience directional change otherwise, within their phytocoenoses. The sorption capacity of their soils nevertheless decreased. Overall, it was possible to note increases over the period in question when it came to numbers of species present in the tree, undergrowth and bryophyte layers. However, while the role of species characteristic for class Nardo-Callunetea increased, that of Trifolio-Geranietea species declined. And, while correlations between vegetation and soil characteristics proved to be different for each of the four groups of communities, there was no precluding model parameters differing significantly from one year of measurement to another.