This article presents the analysis of the allocation of important plant areas (IPA), which urgently identifies the most valuable sites for protecting plant objects. The study is based on a comprehensive inventory of the species composition of plants in the flora of the Western Karatau Ridge and the Mangyshlak Peninsula (arid regions)- key sites Akmysh, Samal, and Kogez, considered standard and the best preserved with natural vegetation cover. The flora of these critical sites was analysed using a combination of field surveys, herbarium studies, and a literature review. The results revealed a rich biodiversity, with 104 species from 82 genera and 33 families. Most species belong to 9 families, making up 60.6% of the total taxa. By the nature of life forms, perennial herbaceous plants dominate in all key sites (30 species, 50.0%). The eco-phylogenetic spectrum showed that a significant share of the flora of the studied IPAs is made up of xerophytes (21 species, 35%) and xeromesophytes (9 species, 15%); desert and mountain-steppe species prevail (53.0%). Rare, endangered and Red Book species account for 10-21.3% of those growing in the region. Regarding economic value, fodder, ornamental, honey, medicinal and food species dominate. The Shannon, Simpson, and Jaccard indices assessed alpha-beta and gamma diversity. The index showed that biodiversity in the Samal and Kogez sites is higher and more evenly distributed compared to the Akmysh site. The Whittaker, Harrison and Cody indices confirm significant differences in the species composition between the sites. In light of these compelling results, a clear and urgent call to action is proposed to allocate these areas to the IPA category, a crucial step towards ensuring the long-term existence of natural biocenoses.