As part of a project to study biorepair of mausoleums in the summer of 2023, the species composition of lichens on the external surfaces of the walls and dome was identified. Lichenologists identified 32 species of lichens developing on the surfaces of the stone structures.
The most common species found were typical calciphilous lichens: Calogaya decipiens, Verrucaria sp., Candelariella sp., Diplotomma venustum, and others.
The study showed that lichen communities cover significant areas of the walls and domes, allowing the condition of the monuments to be classified as a moderate degree of biological degradation.
Of particular interest is the difference in the nature of the damage to the two mausoleums. The Mausoleum of Tur-Khan, built using gypsum-containing rocks, suffers from the gradual leaching of the binding material by rainwater. Lichens actively colonize the resulting voids, exacerbating the degradation process. The Mausoleum of Khuseyn-Bek, constructed from material without gypsum layers, suffers more from the development of higher plants, whose root systems cause mechanical destruction of the stone.
All identified lichen species are common to the region and can be removed during restoration work. The data obtained will form the basis for developing scientifically sound measures for the preservation of these unique architectural monuments.