Golovanov M., Abramova L. M. THE CHALK HILLS OF THE ORENBURG REGION IS A UNIQUE HABITAT OF RARE PLANTS AND PLANT COMMUNITIES // Arid ecosystems. 2019. V. 25. № 2 (79). P. 18-26. | PDF

In the period from 2014 to 2017, floristic, geobotanical and population-biological studies were conducted on 9 Cretaceous elevations of the steppe zone of the Orenburg region, characterized by high specificity and the proportion of rare and endemic species. Floristic studies were carried out by a widespread route method. Assessment of environmental significance is given by 8 indicators adopted in phytocenotic works (floristic and phytocenotic significance, distribution, naturalness, reduction of area, recoverability, category of protection, coverage of protection). 40 species listed in the Red Data Books of different ranks and 15 endemics were found on the studied massifs. The greatest number of rare species of plants marked for Verhnesaldinsky and Trinity Cretaceous mountains (26 species), which are the largest in size and slightly disturbed Cretaceous reference arrays region. High concentration of rare species of plants occurs in saltwort-sagebrush (24) and desert-Agropyron communities (25 species). When assessing the environmental significance by the integral index the higher scores of “category of protection” received communities with dominants: Anabasis, Anthemis and Nanophyton. Assessment of the state of populations of 6 rare plant species on the studied Cretaceous massifs showed that with increasing anthropogenic load there is a decrease in the vitality of populations. The necessity of protection of four unprotected today chalk hills and chalk outputs in the Orenburg region is mentioned.

Keywords: Orenburg region, Cretaceous uplands, rare and endemic species.

DOI: 10.24411/1993-3916-2019-10050