A comparison of the flora and species distribution pattern of seed plants in the Turpan-Hami and Barkol-Yiwu Basins, Xinjiang, China

This research into the flora and species distribution pattern of seed plants in the Turpan-Hami and Barkol-Yiwu basins provides crucial theoretical information on the origin and evolution of species, the conservation of biodiversity, and the development and utilization of plant resources. The two basins are distinct natural geographic units in the Tuha region of Xinjiang that are separated by the eastern Tianshan Mountains. A comparative analysis on seed plant species between the two basins, including the families and genera identified, floristic geographical elements, and the species distribution pattern, yields the following main results. (1) There is a total of 997 species of seed plants in the Tuha region, belonging to 64 families and 373 genera: 738 species in 60 families and 321 genera in the Turpan-Hami Basin and 729 species in 55 families and 316 genera in the Barkol-Yiwu Basin; the density of species in the Turpan-Hami Basin (5.0×10‒3 species·km‒2) is lower than that in the Barkol-Yiwu Basin (13.0×10‒3 species·km‒2). (2) In the Turpan-Hami Basin, families containing 2-10 species and only one species account for 71.67% of the total families; the proportion of genera with one species accounts for 51.09% of the total genera and the species account for 22.22% of the total species. In the Barkol-Yiwu Basin, families containing 2-10 species and only one species account for 70.91% of the totalfamilies; the proportion of genera with one species accounts for 56.33% of the total genera and the species account for 24.42% of the total species. (3) The ratio of tropical to temperate elements at the family and genus levels in the Barkol-Yiwu Basin is lower than that in the Turpan-Hami Basin; this finding indicates stronger temperate characteristics in the former and more pronounced tropical affinities in the latter, revealing spatial heterogeneity between the two basins. (4) The analysis of species suitability using the optimal ensemble model from the Biomod2 package shows that the Barkol-Yiwu Basin has higher species richness than the Turpan-Hami Basin. Species in the Barkol-Yiwu Basin are mainly concentrated in the central-west of the basin, whereas those in the Turpan-Hami Basin are concentrated in the west of the basin. Mean diurnal temperature range, human influence index factors, and mean annual precipitation are the main factors accounting for the distribution patterns. Thus, in the Tuha region, the flora is relatively rich and the geographical composition of families and genera is predominantly temperate; the species richness is higher in the Barkol-Yiwu Basin than in the Turpan-Hami Basin, and the distribution pattern is characterized by a higher seed plant richness in the Barkol-Yiwu Basin than in the Turpan-Hami Basin. These results provide a scientific basis to guide the conservation and sustainable utilization of wild plant resources in the Tuha region, as well as supporting ecological restoration and construction.