The dynamics of the dendroflora ecomorphic and biomorphic spectra at the former Botanic garden of the Kryvyi Rih state educational institute

Abstract

The aim of the work is to identify the features of the temporal dynamics of the ecomorphic and biomorphic spectra at the former Botanic Garden of the Kryvyi Rih State Educational Institute. It was found that on 01.10. 2011 in the plantations of the former Botanical Garden 47 species of trees, shrubs and lianas had grown. In the composition of the dendroflora only five species of gymnosperms and 42 species of angiosperms had been revealed. Leading families were Rosaceae, Fabaceae and Salicaceae and Aceraceae. The dominant genera were Acer and Populus. For the last 40 years, 99 species, 46 genera and 10 families from the collection had been dropped out. At the same time, the Botanical Garden was the only habitat of unique species such as Metasequoia glyptostroboides, Celtis australis, Securinega suffruticosa, Cercis siliquastrum, Indigofera gerardiana, Kerria japonica, Koelreuteria paniculata, Xanthoceras sorbifolium, Schisandra chinensis. At present the scientific collections in our region are lacking in these species. Since that time, the dendroflora’s trofomorphic spectrum of the former Botanical Garden had undergone some changes. The first thing to note is an increase in the proportion of mehatrophes: from 15.5 % in 1966 – up to 25.5 % in 2006 (1.6 times). At the same time the total proportion of olihotrophes and olihomezotrophes had been reduced: from 26.4 % in 1966 to 14.9 % in 2006 (1.8 times). Despite the lack of a clear trend towards changing the proportion of mezotrophes, they are consistently the most common woody plants of the Botanic Gardens. Age-related changes of the dendroflora’s hygromorphic spectrum of the former Botanical Garden have such directions: the proportion of xerophytes decreased in 1.9 times and mezohygrophytes in 2.4 times. However, there has been an increase in the relative number of mezophytes (1.1 times), mezokserophytes (1.2 times) and hygromezophytes (1.6 times). Over the time the dendroflora’s heliomorhic spectrum had the following changes from the former Botanical Garden: despite the decrease in the proportion of heliophytes (from 58.8 % in 1966 to 53.2 % in 2006), they remained the largest group of the spectrum. At the same time it was revealed an increase of scioheliophytes in 1.4 times, and overall reduction of heliosciophytes and sciophytes in the number and proportion. In the plantations of the Botanic Gardens it has been established a tendency of the introduced species reduction and of the native species increase. However, this has not changed the overall pattern – the dominance of the introduced species, both trees and shrubs. On the whole the conditions of the region are the most adapted for megatrophes plants, mesophytes and heliophytes and trees. The basis of the collection consists of introduced species from the Atlantic-North American, East Asian and Tsimkumboreal floristic regions.