The problem of ecological differentiation, anthropogenic transformation and protection of the floodplain phytosystems (flora and vegetation) in the structure of river-valley corridors of Transcarpathian ecological network is devoted in the thesis. The classification structure of the Transcarpathian floodplain vegetation within river-valley ecological corridors consists of 14 vegetation classes, 24 orders, 36 unions and 103 associations. The highest syntaxon diversity level of floodplain vegetation was identified for Borzhavskyi and Latorytskyi ecological corridors, covering all 14 classes of vegetation, which are represented by 77 and 87 associations respectively. The key factors that determine the distribution of vegetation along the river-valley corridors are soil moisture and nitrogen content, between which there is a direct correlation. The soil moisture gradient covers a wide range of variability between parameters of vegetation class Lemnetea (11,25) andArtemisietea vulgaris (5,65). Analysis of morpho-functional features of floodplain species shows a high intensity of absorption of nutrients from the soil and, consequently, the support for intensive development of riverside communities due to a high soil fertility by annually flood deposited nutrients. The efficiency of distribution plants at considerable distances from flood spills was presented. The maximum effective distance transfer plant diasporas along the river-valley corridors are 16-20 km. However, the impact of hydrochory on the structure of plant communities at the local level is negligible. The characteristic feature of riparian zones is the small percentage of local vegetation species in the deposited seeds (less than 23%). Also, only 1.67% seeds of all, which were deposited in silt, retain the ability to germinate. The river-valley ecological corridors showing statistically significant common patterns of distribution of plant communities, especially with increasing altitude overall floristic diversity and number of rare species in communities are reducing. The flat areas of Borzhavskyi, Latorytskyi and Uholsko-Uzhanskyi ecological corridors (between 99 and 200 m above sea level) represent 78.41% of total floodplain species diversity. The floodplain phytosystems (vegetation and flora) of the Transcarpathia characterized by a high nature conservation value. We found 147 species that are red listed of various ranks, including 41 of them belonging to the Red Data Book of Ukraine (2009). Also we found 64 associations here, listed in "Green Data Book of Ukraine" (2009). Of these, among all corridors most syntaxa are submitted for Borzhavskyi ecological corridor (18 associations) and Tysovetskyi corridor (13). The three new protected areas proposals to improve ecological network were prepared in total area of 466 ha. The highest degree of ecological corridor functional capacity was identified for Borzhavskyi, Latorytskyi and Tysovetskyi corridors based on comprehensive assessment several criteria, like availability of natural boundaries, corridor transformation degree, diversity level for species and communities, availability of space for protection and distribution of species and functional stability.
