THE ALLUVIAL FOREST VEGETATION DISTURBED BY THE INVASIVE ALIEN PLANTS, IN THE DANUBE VALLEY, BETWEEN CETATE AND CALAFAT

Invasive species have a negative impact on forest, grassland, and agricultural ecosystems around the world, sometimes associating and forming segetal or ruderal plant communities. Exotic species compete with native species and threaten ecosystem stability. The paper presents the results of the investigations carried out in the alluvial forest vegetation in the Danube Valley from Oltenia, between Cetate and Calafat. In this region, the intensive abiotic activity, but not only that, has brought about the invasion of allochtone (invasive alien) species plants in the natural and semi-natural degraded ecosystems, especially in alluvial forest habitats. The species has been found in the following types of natural habitats: 91E0* -Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae); 92A0 -Salix alba and Populus alba galleries; 91F0 -Riparian mixed forests of Quercus robur, Ulmus laevis and Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia along the great rivers (Ulmenion minoris); 91I0* -Euro-Siberian steppic woods with Quercus spp.