In Poland, the largest stretches of abandoned agricultural areas were formed at the end of the 1980s, along western and eastern borders, among others, in Przemyśl Foothills (Pogórze Przemyskie). Therefore, the research on the diversity of plant communities from abandoned agricultural areas as well as main directions and the rate of succession after the cessation of management was undertaken in the vicinity of twelve municipalities in south-eastern Poland. This research revealed that the dominating direction of changes of the abandoned agricultural area vegetation was vanishing of plant groups with segetal and meadow species and spreading of shrub communities. A general increase in the forestation rate of the researched abandoned agricultural areas from 10-40% of the area in 1970-1971 to about 30-70% in 2003-2004 may be the evidence of the occurrence intensity of those phenomena.
Phytosociological and physicochemical studies of endangered habitats of swamp and peat-bog areas were carried out in the Lower Silesian Forest complex (Western Poland), in the vicinity of Węgliniec village. The total of 63 phytosociological relevés were made and three syntaxonomic units were distinguished as associations (Cicuto-Caricetum pseudocyperi, Typhetum latifoliae, Phragmitetum australis) and two as communities (with Sphagnum girgensohnii and with Juncus effusus). Using the phytoindication method, it was found that among four analysed habitat parameters (L – light availability, F – humidity, R – soil pH, N – soil nitrogen), only nitrogen content did not play a significant role in shaping the composition of these phytocoenoses. Physicochemical studies of surface waters using high performance liquid chromatography (HPLC) method indicated, among others, a higher level of nitrogen compounds in some samples. Concentrations of mineral substances dissolved in water usually exceeded limit values for class II waters. Species composition of phytocoenoses and values of parameters recorded in neighbouring surface waters indicated that mutual interactions of these habitat components clearly existed there.
Although riparian forests are still common in Europe, their variants - similar to natural forests - are rare. They are, as communities, early stages of forest-shrub succession, particularly vulnerable to the expansion of neophytes for which they are an important type of vegetation that enables their spread. In the Ojców National Park (ON P), these types of phytocoenoses are heavily influenced by anthropogenic pressure. The preservation of their biodiversity is particularly difficult because of the fragmentation and small area occupied by the Park - just 2.89 ha. There have been no data on synanthropization of ON P riparian forests until now. The ‘conservation status’ of these communities was determined by examining the degree of anthropophyte participation in their floristic composition. This determination is necessary to take effective preventive measures. In 2012-2014, phytosociological studies were carried out on the ON P riparian communities. A particular attention was paid to the presence and quantitative participation of alien species in research plots. The obtained results revealed that there were 189 plant species in alluvial forests of the ON P, including 80 synanthropic species. The group of synanthropes comprised 32 anthropophytes: 5 diaphytes, 9 archaeophytes and 18 kenophytes.
The paper presents composition of vascular plant species in spring niches in the Ojców National Park (Southern Poland). 111 species of vascular plants, fourteen mosses, two liverworts and one species of ferns were recorded during the first comprehensive study carried out in 2009 and 2010. Plants occurring in these places showed different degrees of association with spring niches. The largest group was represented by accidental krenophytes (74 species), while spring plants - obligatory krenophytes, constituted only a small part of the local flora (5 species). Meadow species of the Molinio-Arrhenatheretea class and forest species of the Querco-Fagetea class, penetrating niche areas from the adjacent areas, were the dominating ones. Plants of aquatic and spring communities were scarce, due to the predominance of small type karst springs. The diversity of vegetation was significantly influenced by habitat factors such as availability of light, humidity or the amount of organic matter in the soil.