Forecasted changes in the suitability of the Vanessa cardui environment in agroecosystems of Ukraine under climate scenarios

Modern climate change significantly transforms the functioning of agroecosystems and affects the spatial dynamics, abundance, and potential harmfulness of migratory phytophages in the temperate climate zone. In this regard, it is particularly important to study possible changes in the ecological niches of species capable of responding quickly to changes in climatic parameters. One such species is the painted lady butterfly Vanessa cardui (Lepidoptera: Nymphalidae), which is characterised by high migratory ability, broad ecological plasticity and the potential to form significant populations in agricultural landscapes. The aim of the study was to assess the current and projected suitability of the environment for Vanessa cardui and to determine possible changes in its potential range under different climate change scenarios. The analysis used georeferenced data on the species' localisation obtained from global biogeographical databases, which were combined with bioclimatic variables based on CMIP6 climate projections. Habitat suitability was modelled using the entropy maximisation (MaxEnt) algorithm, which is widely used to model the potential distribution of species based on presence-only data. The quality of the models obtained was assessed using AUC indicators and ROC curve analysis. The modelling results showed that the spatial distribution of Vanessa cardui is largely determined by temperature seasonality, the average temperature of the warmest quarter, and the amount of precipitation during the growing season. Forecasts indicate a possible redistribution of territories with varying levels of ecological suitability, an increase in the spatial mosaic of the environment, and fragmentation of optimal habitats under scenarios of more intense climate stress. At the same time, a significant part of the studied region retains a moderate level of environmental suitability for the species, which indicates not an unambiguous expansion or reduction of the range, but an increase in the variability of living conditions and potential instability of populations. The results obtained indicate a possible transformation of the balance between phytophagic pressure and natural ecological regulation in soybean agroecosystems, which is caused by changes in climatic parameters. The proposed approach to forecasting can be used in phytosanitary risk assessment systems, improving monitoring programmes and developing adaptive strategies for managing agroecosystems in conditions of climate uncertainty.