Some rare plant species in the Aktolagay cretaceous massif (Republic of Kazakhstan): the characteristics of populations

Cretaceous massifs of the Eurasian continent is unique not only for its geological features, but also for the peculiar flora, therefore, identification and study of the biodiversity of these unique objects is currently an urgent task. Comprehensive studies of the flora and vegetation of the Aktolagay cretaceous massif (Republic of Kazakhstan) were carried out in 2019. One aspect was the consideration of the ecological and biological features of several plant species characteristic for this territory. The research is devoted to the study of 5 plant species: Astragalus lasiophyllus Lеdеb., Astragalus vulpinus Willd., Matthiola tatarica (Pall.) DC., Eremurus inderiensis (M. Bieb.) Regel, Tragopogon ruber S.G. Gmel. on the territory of the Cretaceous massif Aktolagai. The coenopopulations of the species are located in the lower parts of the slopes, as well as aligned areas at the foot on cretaceous substrates, and on sandstone soils. The arithmetic density of the studied CPs varies from 2.2 to 6.6 ind./m2, the effective density varies from 1.6 to 4.9 ind./m2. The studied coenopopulations belong to normal incomplete ones. The most typical feature is the absence of seedlings, juvenile and senile individuals in the spectrum, while the peak falls on mature generative individuals, in the Mattiolla tatarica coenopopulations - on virginile individuals. Coenopopulations are heterogeneous in their type ("delta-omega" criterion): the Matthiola tatarica one is young, the CP of Astragalus lasiophyllus is transitional, the CPs of Astragalus vulpinus and Eremurus inderiensis are maturing, and the CP of Tragogon ruber is mature. The recruitment index in the studied populations is rather high (0.36–3.05), the agting index is equal or close to zero. Most morphometric features show low levels of variability and plasticity.