Spatial patterns of species richness and endemism of Acantholimon (Plumbaginaceae) in Uzbekistan: implications for conservation in Central Asian mountain flora

The mountains harbor considerable diversity of Acantholimon Boiss., but broad-scale patterns of documented richness, endemism, elevation, and range restriction remain poorly quantified. We analyzed 269 georeferenced records of 28 species (1870–2016; two records undated) using a 20 × 20 km grid, fixed 200 m elevation classes, and GeoCAT. Records occurred in 95 out of 1,262 cells, with one to five species per occupied cell; the highest documented cell richness occurred in northern Nuratau (AC46). Ten national endemics (35.7%) occupied 17 cells. AC46 and Hissar cell AM49 each contained three national endemics, but together represented only six of the 10 species. Raw elevation frequencies placed 150 records (55.8%) between 1,600 and 2,800 m, with the highest 200 m class at 2,000–2,200 m (n = 30). The exact species–coordinate deduplication retained 260 records and the same modal class, although the frequencies were not standardized by available land area or collecting effort. Preliminary GeoCAT screening according to IUCN criterion B2 identified four endemics below the AOO threshold (< 10 km²) and six below the EN level threshold (≥ 10 and < 500 km²). The minimum convex polygon EOO could not be calculated for three taxa represented by fewer than three occurrence points. These grid- and record-dependent results identify priorities for standardized field reassessment, not definitive biological hotspots, representative conservation networks, or formal IUCN categories.