Оntogenetic and popula­ tion analysis of Sinapis rvensis L. in agrocenoses of Right-Bank Forest-Steppe of Ukraine

This article presents the results of a comprehensive ontogenetic-population analysis of the adventive species Sinapis arvensis L., a significant component of the segetal flora in the agrocenoses of field crops in the Right-Bank Forest-Steppe of Ukraine. The research was conducted over a multi-year period (2013–2024) on private farms located in Odesa and Vinnytsia regions, which allowed for tracking the dynamics of population changes under various agricultural practices. This species was conditionally identified as a model object for further studies of invasion pro­cesses, due to its high segetal potential, confirmed by consistently high abundance indicators, significant projective cover, and high frequency of occurrence in all studied agrocenoses. These characteristics de­monstrate the successful adaptation of S. arvensis L. and its dominance in the agroecosystems of the re­gion. A detailed analysis of the age structure of S. arvensis L. populations revealed their high density and the formation of full-membered right-sided spectra of ontogenetic states. This means that populations include all age groups — from seedlings and juvenile forms to adult virile, generative, and senescent individuals. Such full-membership is a critical indicator of population stability and its ability for effective self-reproduction even under intensive anthropogenic pressure. The presence of all life cycle stages confirms the species’ existence in conditions of ecological and phytocenotic optimum. The application of the quan­titative «delta-omega» (Δ/ω) classification by Zhivotovsky allowed for establishing that S. arvensis L. populations primarily belonged to young and matur­ing types. However, long-term monitoring revealed significant dynamism in the ontogenetic structure of populations and its dependence on the type of agro­ cenosis: in the agrocenoses of winter cereals (winter wheat, winter barley) and oilseeds (winter rapeseed), a «rejuvenation» of populations was observed in the period 2017–2024. This is likely linked to the in­ tensification of agricultural practices, which elimi­nate older individuals but create conditions for the mass germination of seeds from the soil seed bank.In unflower and corn crops, S. arvensis L. populations maintained a young status, indicating consistently fa­vorable conditions for intensive population renewal in these cultures; сonversely, in sugar beet agrocenoses, a tendency for the population to transition to a mature stage was recorded. This may suggest the formation of more stable and self-reproducing communities, possibly due to the specificity of agricultural technologies or lower competitive pressure in these crops, allowing a larger number of individuals to reach reproduc­tive age. This observed dynamism in the ontogenetic structure of populations and its dependence on a complex of ecological, phytocenotic, and anthropo­genic factors underlines the high ecological plasticity of S. arvensis L., its exceptional competitiveness, and its ability for effective persistence in agrocenoses. The obtained results are of fundamental importance for understanding the bioecology of invasive species and serve as a scientific basis for developing effective integrated control systems for wild mustard, aimed at minimizing its negative impact on the productivity of agricultural crops under intensive farming conditions in Ukraine.