Biotic homogenization of dendroflora in the conditions of the megapolis (Dnipro, Ukraine)

Abstract

It was established that artificial stands of trees in the Shevchenko Park are capable of forming a sufficient amount of viable undergrowth of autochthonous and introduced (adventurous) species.  The indexes of species richness of Margalef and Menkhinik of self-regenerating tree species for the site with a strong recreational load turned out to be the largest (due to adventitious species) compared to the sites with no and moderate recreational load. Koch index of biotic dispersion is 50.0%. Correlation coefficients between the number of allochthonous and autochthonous tree species that have self-regenerated for the studied areas with strong, moderate and no recreational load are statistically significant (0.73, 0.76, 0.77 respectively).

The calculated index of biotic dispersion testifies to the presence of a process of floristic homogenization of the forest stand on the territory of the park. As part of the adventitious fraction of the self-regenerating dendroflora, there is an increased invasion of Ailanthus altissima and the occurrence of such neophyte species as Celtis occidentalis and Acer negundo, which indicates the penetration of alien species into the local flora and a potential threat to natural floristic diversity.