Ecological Systems and Devices Annotation << Back Dynamics of the State of Legume Coenopopulations in the Complex true Steppe of the Chui basin under Conditions of Pasture Load Karnaukhova N.A., Zvereva G.K. The development of desertification processes and the appearance of bare spots in the complex steppe of the Chui basin of the Altai Republic are associated with intensive pasture load. Overgrazing has a sharp effect on the deterioration of the forage qualities of the grass stand due to the loss of valuable forage plants, including those from the Fabaceae family, and leads to the growth of Potentilla astragalifolia, Artemisia frigida and Bassia prostrata. In order to assess the state of leguminous plants under unregulated grazing, monitoring studies of coenopopulations (CP) of Astragalus laxmannii subsp. laxmannii, A. brevifolius, A. tibetanus, Oxytropis argentata from 2016 to 2022. The impact of pasture load on the communities of the complex steppe was assessed by the stages of pasture digression and above‒ground mass reserves; the state of the CP of species was assessed by changes in the ontogenetic structure and morphometric indicators. In the conditions of solonetz-steppe complex of the Chui basin, due to the arid climate and grazing, the reserves of aboveground phytomass varied greatly. Thus, in the grasses community, the mass of grasses in July fl uctuated from 129 to 7 g/m2 , and that of forbs – from 89 to 0.2 g/m2 of air-dry mass. In the wormwood community, the reserves of live aboveground phytomass are 1.4–3.3 times smaller; the variability of the accumulation of mass of agrobotanical groups is also high here. With increasing pasture digression in the ontogenetic structure of the CP of various legume species, accelerated aging processes occurred, which over several years of observation led to the accumulation of old generative and post-generative plants. This determined the sequence of changes in the ontogenetic structure of the CP from young or transitional to old. The study of the effect of grazing on the morphometric parameters of plants from the Fabaceae family showed that an increase in the grazing load in the complex true steppe leads to the minimization of all morphological indicators of the studied species. Nevertheless, despite the drought conditions and increased pasture digression from 2016 to 2022, all the studied legume species remained in the herbage of the complex steppe and many CP can successfully recover from renewal buds on the caudex or underground rhizomes, provided that grazing is reduced or temporarily stopped. Keywords: Chui basin of the Altai Republic, complex steppe, pasture digression, species of the Fabaceae family: Astragalus laxmannii subsp. laxmannii, A. brevifolius, A. tibetanus, Oxytropis argentata, ontogenetic structure of coenopopulations. DOI: 10.25791/esip.2.2026.1572 Pp. 03-16.