Characterization of the Wild Trees and Shrubs in the Fergana Valley: Diversity and Distribution, Threats

This study aimed to investigate the floristic characteristics, biogeographic distribution, and altitudinal zonation of native trees and shrubs (over 50 cm in height) in the flora of the Fergana Valley (Uzbekistan). Field surveys at 32 sites recorded 165 species from 60 genera and 32 families, including 5 (3.03%) subendemic taxa listed in the national Red Book. Among the families, 14 are represented by a single species each, 10 families by 2-9 species each, and 5 families by 10-15 species each, while the family Rosaceae is represented by 42 species. 26 genera were each represented by a single species, while 34 genera were each represented by 2-10 species, and the genus Rosa was represented by 11 species. Among the life forms represented in the dendroflora, phanerophytes are the most dominant (135 taxa), followed by chamaephytes (30 taxa). The results of the floristic analysis revealed a clear predominance of temperate taxa across all hierarchical levels. At the species level, Central Asian and Temperate Asian elements together accounted for 87.89% of the flora, indicating the distinctly temperate nature of the regional dendroflora and underscoring the crucial role of endemic species in maintaining biodiversity. All taxa inhabit six natural habitat types. Botanical-geographic analysis of the highest species richness was found in the Chorkesar (62.42%) and Eastern Alay (52.72%) regions, while the East-Fergana region contained the lowest (11.51%). According to the results of altitudinal distribution, mountain areas harbored the highest tree and shrub diversity (112 taxa), while the high-altitude pasture zone is the poorest (7 taxa). The highest diversity along horizontal and vertical gradients was observed in the Rosaceae family (300-3100 m), with peak species richness recorded between 1400 and 2100 m. These findings provide an important scientific reference for identifying regional biodiversity hotspots, conserving rare species, supporting future floristic and biogeographic research.