Dry grassland ecosystems are highly fragmented in Ukraine and increasingly threatened from intensification of farming practices. Evaluation of the habitat conservation importance based on multitaxon studies allows for optimizing selection of priority sites. Botanical research of xerothermic habitats in the Kryvorizkyi Iron Ore Basin has been conducted since 2012, while spiders were investigated for the first time in 2017. In the four study sites, we recorded 265 vascular plant species (23 under protection) and 95 spider species (19 are rare). Both vegetation and spider communities of the site Zelena Gully are well preserved and rich in rare and threatened species (18 plant and 11 spider species), which confirms its value as a priority site of the Emerald Network. Chervona Gully and the Slate Rocks should be included in the network. Frequent fires and intensive grazing in Khrystoforova Gully affect the spider diversity, decreasing the number of specialist and rare species, while early flowering plants benefit from this disturbance. Nevertheless, its vegetation is poorer than in Zelena and Chervona gullies. Inclusion in the Emerald Network is critically important to the investigated sites, since expansion of mining activities is constantly threatening natural habitats in industrial regions.