Modern state and vital structure of natural populations of Cephalaria uralensis (Murr.) Schrad. ex Roem. et Schult. rare species in the South Urals

Studying rare species of plants on the borders of their distribution is an important and relevant problem of modern botany and plant protection. During the work with rare species of plants which grow under different ecological conditions and are under different extent of anthropogenic influence, morphometric methods are one of the main ways of obtaining representative volume of data about individual plants and the state of particular populations. Cephalaria uralensis (Murr.) Schrad. ex Roem. et Schult. belongs to rare species in the Bashkortostan Republic, a poorly studied species which is found on the northern and near eastern frontier of the area in the Bashkortostan Republic. This species is included in "The Red List of the Bashkortostan Republic" where it is referred to category III - rare species. The aim of our work was to study morphometric parameters and identify the vitality structure of Cephalaria uralensis cenopopulations in the Bashkortostan Republic. In 2014, we investigated the steppe zone of the Cis-Urals in the Bashkortostan Republic on the territory of 8 administrative regions of the republic. As a result, we revealed and examined 16 cenopopulations. We studied the morphometry and vitality composition in nature by standard techniques on 25 middle-generative individuals. Also factorial and correlation analyses were carried out. The general density in cenopopulations of Cephalaria uralensis varies from 2.2 to 10.3 ind./m . The cenopopulation 7 has the maximum values of density indicators, high values are noted also in cenopopulations 11 and 16. The minimum values of density are noted in cenopopulations 1 and 9. In the majority of morphometric parameters the cenopopulation 4 is in the lead, where optimum conditions of plant growth are created. Also, cenopopulations 6, 7 and 11 growing on poorly broken slopes have high values of parameters. The minimum values are in all respects noted in cenopopulation 2, strongly broken by a cattle pasture. The assessment of interpopulation distinctions by method of dispersive analysis showed statistically significant influence of conditions of ecotope of concrete cenopopulation on all studied signs of plants (р < 0.001). Level of factorization makes from 15% to 53%. The results of canonical analysis revealed that the coefficient of canonical correlation between vegetative and generative structures is equal 0.635 and has 100% reliability (p = 0.000000). It shows that the development of generative bodies depends on the development of vegetative structures. The vital state of Cephalaria uralensis cenopopulations changes in different ecotopes. In nine cenopopulations the prevalence of individuals of the highest class is noted, and they are referred to the prospering category, these cenopopulations are associated with undisturbed or poorly broken habitats. The index of quality of cenopopulations makes 0.38-0.5. Other cenopopulations are considered depressive, the quality of population makes from 0.1 to 0.3. These are, as a rule, brought-down pasturable communities. Apparently, with the general eco-coenotic stress caused by strong pasturable loading, the growth processes of Cephalaria uralensis individuals are considerably suppressed. The research data could be used for improving protection of rare species populations on the territory of the Bashkortostan Republic.

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