Diversity, distribution patterns, and floristic characteristics of seed plants endemic to Tibet, China

Based on the list of endemic seed plants of Tibet, combined with the natural geographic distribution of species, the composition characteristics of family, genus, and species diversity, species life-form diversity, vertical altitude and county-scale distribution patterns, and floristic properties at the genus level were analyzed, with endemic species hotspots also identified. Results showed 1 079 species of endemic seed plants in Tibet, belonging to 89 families and 297 genera, with high specificity. Among the identified plants, 19 families contained more than 20 species, and Asteraceae contained the most endemic species. In total, 24 genera contained more than 10 species, with Delphinium and Berberis identified as the most endemic genera. Perennial herbs accounted for the highest proportion (66.4%) among endemic plants. In terms of floristic composition, temperate genera were dominant (61.6%). Medog County contained the largest number of endemic species (271 species). In general, the distribution pattern of endemic seed plants in Tibet was extremely uneven, with the southeast Himalayas showing the highest richness. The endemic seed plants also exhibited an extremely wide altitudinal range, showing a single-peak species-richness distribution pattern along the altitudinal gradient, concentrated at 3 000–4 500 m. The results of this study provide basic plant data to support the prioritization of plant diversity conservation in Tibet, the establishment of a red list, and the construction of a natural protection system in the future.