SPECIES DIVERSITY AND STRUCTURE OF THE SAXICOLOUS FLORAL COMPLEX IN THE AKTOBE FLORISTIC DISTRICT

Abstract

The study of the Aktobe floristic district is a relevant task for assessing anthropogenic factors’ impacts on the flora of the steppe zone and developing measures to reduce the adverse effects of mining, metallurgical, and oil and gas facilities on the biodiversity of plant communities. The timely study evaluated the species composition and analyzed the saxicolous floral complex of the Aktobe floristic district, one of the most fascinating complexes based on florogenetics. The saxicolous complex flora comprised 219 species belonging to 119 genera and 39 families. However, the 10 leading families of the conglomerate manage 75.0% of the species composition of the saxicolous complex. Previous validations revealed that the saxicolous floral complex features have dominant families of Caryophyllaceae, Boraginaceae, and Chenopodiaceae and a more significant role for the Rosaceae and Scrophulariaceae. The saxicolous complex specificity has demonstrated the genera Potentilla and Centaurea as 2nd and 3rd position holders, respectively, and the presence of the genera Orobanche, Lappula, Atraphaxis, and Allium as the leading genera; however, they are unregistered among the other floral complexes. The analysis of geographical habitat types has shown that the Black Sea/Kazakhstan, Volga/Kazakhstan, and Eastern ancient Mediterranean habitat types are predominantly characteristic of the saxicolous floral complex. Twelve endemic species have also received recognition, assembling 60% of the endemic flora. Based on the analysis of species habitat, its ecological and biological features, and paleobotanical material available in literature sources, researchers have identified two groups of miscellaneous plants (Neogene and Quaternary) with their ages and endemic plants. Data also indicated the formation of the chief autochthonous core of the flora in the Pleiocene-Holocene.