Floristic analysis of riparian areas in the Timok catchment area (Eastern Serbia)

Riparian areas have long been exposed to extensive human pressures, contributing to their degradation and changes in plant community composition. Consequently, our aim was to analyze the floristic characteristics of riparian vegetation of these anthropogenically-affected areas in the Timok catchment area. Fourteen riparian field sites distributed along 3 rivers (Beli Timok, Crni Timok and Grliška reka) were studied. Vegetation data was collected on 100 m long longitudinal transects, with a total of 70 relevés (five per field site) made. Across the analyzed field sites, a total of 106 plant taxa were recorded. The most common plant species across the analyzed field sites were Bidens tripartita and Salix alba, found at 12 field sites (85.7%). Similarly, they were also recorded in the highest number of relevés: 56 and 47, respectively. Regarding the biological spectrum, hemicryptophytes were the dominant life form (32.06%), followed by therophytes (25.47%) and phanerophytes (24.52%). Floristic elements were grouped into eight areal types, dominated by species of Eurasian origin (35.85%). The presence of 23 alien species (21.7%) is especially alarming. Five invasive alien species with the highest number of records were: Xanthium strumarium subsp. italicum (38), Amorpha fruticosa (38), Erigeron canadensis (36), Echinocystis lobata (30) and Robinia pseudoacacia (21).