Floristic diversity of the Nuratau Mountains: a 150-year retrospective analysis

The Nuratau Mountains located in the central part of Uzbekistan, in the transitional zone between the Mountain Central Asian and Turan phytogeographical provinces, are recognized as one of Key Biodiversity Areas within the Mountains of Central Asia Global Biodiversity Hotspot. These medium-altitude semiarid mountains are identified as one of centers of endemism and priority areas for conservation of plant diversity. This article provides a retrospective review of a 150-year history of scientific exploration of unique flora of this region, highlighting key publications and findings, herbarium collections and collectors. Overall, 1% of herbarium specimens from the Nuratau Mountains were gathered in the 19th century; 69% of all records were made during the 20th century, and 30% of the data were collected since 2000. An essential source of information on the flora of the Nuratau Mountains and the spatial distribution of species is the National Herbarium of Uzbekistan (TASH), which contains over 6,600 specimens from this region or 59% of all occurrence records. According to the most recent assessment, the flora of the Nuratau Mountains includes 1,283 species of vascular plants belonging to 474 genera and 86 families. Of these, 1,180 species from 444 genera and 81 families are native, 32 species are endemic, and 103 species are alien (occasional or introduced). Nevertheless, the flora of Nuratau Mountains is still insufficiently documented, and an actual checklist remains unpublished to date. Comprehensive botanical studies in this region are crucial because of rapidly increasing rates of biodiversity loss and degradation of ecosystems caused by anthropogenic impact.