Historical and Contemporary Impacts of Land Use on the Functioning of the Fraxino-Alnetum Community in the Biała Przemsza River Valley (Case Study, Southern Poland)
Abstract
River ecosystems play a key role in both natural and urbanized environments, acting as essential links in ecological systems. However, they are increasingly exposed to the synergistic effects of anthropogenic pressure and hydrological instability. This study aims to identify and assess changes in land use and their impact on the phytosociological structure and functioning of ash-alder (Fraxino-Alnetum) patches in floodplains. Based on cartographic analyses (1941, 1961, 2025) and detailed geobotanical surveys (2024–2025) conducted at six representative sites, the spatio-temporal dynamics of land use and vegetation habitat conditions were evaluated using ecological indicator values. The results indicate a substantial landscape transformation: a transition from areas dominated by agricultural and forest ecosystems to zones heavily altered by urban expansion, transport infrastructure, and industrialization. Phytosociological analyses show that while species richness remains relatively stable, floristic composition is changing due to hornbeam succession and the emergence of mesophilous species. The presence of non-native species indicates ongoing anthropization in plant patches. Furthermore, hydromorphological modifications, including bank reinforcement and channel deepening in the vicinity of sports and railway infrastructure, have hindered natural river dynamics and accelerated floodplain drainage. The observed changes indicate that ash-alder forests in the Biała Przemsza valley are in a transitional phase between riparian and oak-hornbeam communities, with a clear oak-hornbeam transformation evident in many areas, driven by changes in water relations. This study highlights the urgent need to implement integrated restoration strategies that account for both hydrological catchment recovery and the mitigation of urban pressure to ensure the long-term resilience of riparian ecosystems.