Abstract
The article is devoted to the assessment of the state of coenopopulations of the plant Linaria cretacea, a rare species that needs special protection, by botanical methods. To study the age structure and ontogenetic state of rare species in the Aktobe region. L. cretacea coenopopulations, test sites were built for Akkudyksai, Kopaly, and Utek coenopopulations in the populations of the Ishkargantau chalk massif. The age structure and ontogenetic state of the registered individuals of the species were determined, and the demographic situation in the coenopopulations, the values of the age index and the energy efficiency index, i.e., "delta-omega", and the indicators of recovery, exchange, and aging were calculated. In the results obtained, the average density of the species around coenopopulations and the average number of plants in different age states in the sample sites were calculated. According to coenopopulations, indicators were determined to determine changes in the demographic situation. The soil cover of the coenopopulation consists of gravelly chalk formed by sedimentary rocks of the Cretaceous period. In the soil where L. cretacea plant populations are found, facultative calcefites are twice as dominant as obligate calcefites. Studied rarely, the base spectra of L. cretacea coenopopulations are of a single and mature type. In the future, based on the results obtained, it will be possible to make recommendations for the conservation and protection of this rare species.