Impact of Rosa rugosa and Hippophaё rhamnoides invasion on the pattern of plant communities of Russian Baltic Sea coasts

The consequences of adventitious Rosa rugosa Thunb. and Hippophaл rhamnoides L. invasion in coastal plant communities of Russian Baltic Sea coasts are considered. The phytocoenoses dominated by Rosa rugosa reduce species diversity. The Ellenberg light values in these communities decrease with increasing cover of rose. Negative effects of Rosa rugosa invasion are compensated by protecting sand coast from erosion. Compared to rose sea-buckthorn has less influence on the floristic composition of coastal phytocoenoses and their environment.