Habitats and population structure of rare orchids from the genus Cypripedium in Siberia

Cypripedium calceolus L., C. macranthos Sw. and C. ventricosum Sw. are rare Eurasian orchid species, whose habitats are poorly studied in Siberia. In this paper, we describe 55 sympatric and 10 separated populations of the three species, located in Russia within Republic of Buryatia, Irkutsk Region, Krasnoyarsk Territory, and Republic of Altai. Cypripedium macranthos plants dominated the most of the sympatric populations. Vegetation surveys were performed in all localities, and the collected data were analyzed using the IBIS software. We applied the phytoindication scales elaborated by Tsatsenkin and his colleagues for ecological indicator value analysis. The Cypripedium populations were characterized by high floristic diversity of their habitats; however, all of them were found in areas where both canopy density and ground cover were low. In the most of the separated populations, ontogenetic spectra of Cypripedium species corresponded to the base spectrum with a predominance of the adult vegetative and reproductive shoots.