Geographical structure of rare exotic dendroflora of protected parks of the Steppe of Ukraine

Анотація

Today one of the most burning issues is to save a phytodiversity not only in Ukraine but also worldwide. Therefore an inventory of endangered species of dendroflora in situ, ex situ and in vivo of different administrative and natural regions of Ukraine is one of the components of the solution of this problem. An essential scientific basis of inventory of species is their structural floristic analysis.

The objects of our research were rare exotic species of trees ex situ of non-natural reserves of the Steppe of Ukraine. The subject of the research was a geographical structure of endangered dendroflora in this region. The main research material was a list of species inventoried by us according to the literature, other information sources, and our own data for 2009-2014 years. The analysis of the origin of species of floristic regions of the world was based on A. L. Takhtadzhyan’s Earth floristic zone division. Restriction of the exotic species of dendroflora originating from various floristic regions of the world, to physiographic regions of the Steppe of Ukraine was made according to the physiographic zones division of Ukraine.

In the course of our study we have identified 174 exotic species ex situ of dendroflora of nature reserves of the Steppe of Ukraine, and most of them come from Irano-Turanian, Eastern Asiatic and Circumboreal Regions, which generally account 48.9% of the total number of species. Thus, it shows their high similarity of natural climatic conditions of the Steppe of Ukraine. Interesting is the fact that the vast majority of exotic species from different floristic regions represents Pinophyta, except Irano-Turanian Region (most angiosperms origin from there).

The process of acclimation of rare exotic arboreal species of world flora to the conditions of physiographic regions of the Steppe of Ukraine is limited with general moisturing regime, which is largely dependent on orographic factors. Therefore, investigated species grow mainly in the more dampish highland Donetsk region, and drought-resistant species prefer lowland areas; this indicates the affinity of abiotic autochthonous and introduction growth conditions.