Alien Dendroflora of Almaty Oblast and Assessment of Its Invasiveness

Abstract

The article presents results of studying the distribution of alien species on the territory of six districts of Zhetysu oblast, located in the Southeastern Kazakhstan. The data obtained will make it possible to summarize up-to-date information about the state of ecosystems with invasive plant species, predict their further spread, and develop a strategy to control them. The objects of research were natural ecosystems of Zhetysu oblast, confined to the Balkhash-Alakol and Zhongar-Alatau floristic districts. To identify alien species, monitoring sites were laid with the calculation of native species, introduced species, the species prone to naturalization, and those with self-seeding. The aggressiveness of naturalized species was assessed according to a modernized scale developed at the Institute of Botany and Phytointroduction, Committee of Forestry and Wildlife, Ministry of Ecology, Geology, and Natural Resources of the Republic of Kazakhstan. The territory under study includes two State National Nature Parks and a State Nature Reserve. Eighty-one alien species of woody plants have been identified within settlements and adjacent territories. Some of them are included in the cultivated flora, which do not show a tendency to naturalization in the region. Seventeen species of alien woody plants have been identified in natural ecosystems, which have the potential for naturalization with a high propensity for seed and vegetative reproduction. The percentage of sites with the presence of invasive species varies from 61 to 91%. The highest aggressiveness score (6–8) was assigned to six species: Acer negundo L., Ulmus pumila L., Quercus robur L., Prunus × domestica, Fraxinus pennsylvanica, Ulmus laevis Pall.. Despite the fact that, in the Alakol and Sarkand districts, most of the territory falls within the dry-steppe and semidesert zones, only 8.6% of sites without types of invasive fraction were noted, owing to widespread dispersion of particularly aggressive “edificators”: A. negundo, U. pumila, etc. All identified species mesophytic by their nature in the secondary range show themselves highly adaptive, plastic, and competitive in xerophytic conditions.