Home – Home – Jornals – Contemporary Problems of Ecology 2025 number 1

Based on the results of computer modeling of the Altai-Sayan endemic species Euphorbia pilosa L. (Euphorbiaceae) distribution in Western Siberia, where the main part of its range is located, areas of accumulation of species registration points were identified that largely coincide with the climatic optima of the forecast model. A set of variables with a high contribution to the forecast model was established, including the long-term average monthly precipitation in August (14.1 %), the amount of precipitation in October (13.4 %), the seasonality of surface air temperature (11.4 %) and the long-term average monthly precipitation in May (10.7 %). The contribution of climatic variables characterizing the amount of precipitation significantly, more than twice, exceeds the contribution of climatic variables characterizing surface air temperature. In contrast, the total contribution of bioclimatic indicators is noticeably, more than 1.5 times, higher for air temperature indicators than for precipitation indicators (18.7 % versus 8.6 %). According to the forecast model, one of the well-defined climatic optimums is located at the northern limit of the species distribution in Western Siberia, in the vicinity of Tomsk. To identify the ecological features of the range within the Tomsk climatic optimum, a model site characterized by the highest predicted values of the probability of the species presence was selected. Using the method of latitudinal and longitudinal bands, sites with a relatively high number of species registration points were identified, and sites with the most favorable climate were determined based on the values of the probability of the species presence indicator. The obtained results are correlated with the possible impact of anthropogenic load within the boundaries of the Tomsk urban agglomeration, where deforestation in areas allocated for gardening associations and societies, construction of linear suburban and suburban infrastructure facilities (highways, railways, etc.) leads to changes of the phytocenotic confinement of the species and fragmentation of parts of its range at the northern limit of distribution in Western Siberia.