The widespread distribution of wolf poison (Stellera chamaejasme L.), spanning from southern Russia to southwestern China and the western Himalayas, contributes to its prevalence as an invasive species in grassland ecosystems. Its extensive range, coupled with its ability to thrive in harsh environments, enables it to rapidly colonize grasslands. Once established, it rapidly spreads and dominates large areas. This process inevitably leads to grassland degradation over time, thereby exerting significant impacts on both ecology and economy. In China, grasslands (26.45 million ha, 27.5% of land area) face severe degradation, with more than 90% impacted by overgrazing and climate change. Stellera chamaejasme infestations exceed 1.4 million ha in Qinghai, 546,700 ha in Gansu, and 133,000 ha in Inner Mongolia, causing annual forage losses of 137,500 Mg and economic damages of 15 to 20 million yuan in Gansu alone. These impacts threaten ecosystem stability and pastoral livelihoods. Therefore, research on the mechanisms of spread of invasive plants is crucial. In this comprehensive description, we investigated the effects of S. chamaejasme on plant communities and herbivore interactions. Our research showed how this species successfully invades grasslands and establishes itself as a dominant species. Stellera chamaejasme enhances its expansion by altering soil physicochemical properties, reducing nutrient cycling, and increasing pathogenic fungi abundance while enhancing microbial diversity, creating self-favoring soil conditions. With high genetic diversity, robust reproductive capacity, and potent allelopathic effects, it suppresses neighboring vegetation and escapes herbivory due to toxicity, accelerating invasion. These interrelated traits facilitate the rapid invasion and spread of S. chamaejasme on grasslands, ultimately leading to its dominance. This trend poses a significant threat to the health and stability of the grassland ecosystem. Future research should delve into the ecological adaptability and allelopathic mechanisms of S. chamaejasme, aiming to develop effective management strategies for controlling its spread and promoting grassland recovery and biodiversity conservation.

The paper presents the results of studies aimed at assessing the variability of respiratory activity of soil microbiota (rates of basal and substrate-induced respiration), as well as of the content of organic matter carbon and microbial biomass carbon in soils formed and functioning in natural (slightly damaged) biogeocenoses along altitudinal gradient from the foothills to the high mountain regions of the Central Caucasus (500-3500 m a.s.l., Elbrus variant of altitudinal zonality, Kabardino-Balkaria). It is shown that the mean values of the studied indicators in surface horizons (0-10 and 0-20 cm, depending on the soil type) significantly increase with the altitude from mountain chernozems to subalpine mountain-meadow soils and significantly decrease at the maximum altitude in the zone of alpine mountain-meadow soils. The studied indicators in different soil types within the same altitudinal zone also differ; this difference is statistically significant (t > 2.5; p < 0.02) for most of the indicators for the compared pairs of soil types. The data obtained indicate that the impact of the altitudinal gradient is significantly transformed by additional factors. The multi-regression analysis has been performed to identify the effect of the main factors of relief (elevation above sea level and slope aspect and steepness) and climate (19 bioclimatic characteristics) on the studied indicators. It shows that the mean cumulative contribution of all 22 factors to the variation of the studied indicators is 40% in mountain chernozems, 66% in mountain-meadow chernozem-like soils, 31% in mountain meadow-steppe subalpine soils, 67% in subalpine mountain-meadow soils, and 67% in alpine mountain-meadow soils. Thus, the effect of the considered factors may significantly differ both for soils located along the altitudinal gradient and for soils functioning within the same altitudinal zone. Relief and climate play an important, but not the only, role in the formation of properties of mountainous soils in the Central Caucasus.