Status and ontogenetic structure of Codonopsis bactriana (Campanulaceae) in southwestern Uzbekistan

Codonopsis bactriana F.O. Khass., U. Kodyrov & A. Myrz. is a rare endemic medicinal species distributed in the mountainous regions of southwestern Uzbekistan. The present study aimed to assess the current status and ontogenetic structure of natural populations of C. bactriana under different ecological and phytocoenotic conditions. Field investigations were conducted during 2023–2025 in the Surkhandarya and Kashkadarya regions, where eight cenopopulations were identified and analyzed. The ontogenetic structure was studied according to discrete ontogenetic stages, and population dynamics were evaluated using demographic indices and the Δ–ω classification. The results revealed four types of ontogenetic spectra: left-skewed (CP3, CP7), centered (CP1, CP5, CP8), bimodal (CP6), and right-skewed (CP2, CP4). Most cenopopulations exhibited unimodal, centered spectra with a peak at middle-aged generative individuals, indicating relatively stable population dynamics. Population density ranged from 0.8 to 2.7 individuals/m², while ecological density varied from 0.94 to 3.17 individuals/m². Recovery index values exceeding unity in most cenopopulations suggest effective seed regeneration, whereas relatively high aging indices in several populations indicate increasing aging trends. According to the Δ–ω classification, the studied cenopopulations were categorized as young (CP3, CP6, CP7), transitional (CP8), mature (CP5), maturing (CP1), and old (CP2, CP4). The main factors influencing population structure included unsystematic harvesting by local populations, grazing pressure, and geological exploration activities. These findings provide important insights into the population status, regeneration potential, and conservation requirements of Codonopsis bactriana in southwestern Uzbekistan.