Adaptation of invasive species of Solidago canadensis L. in the urban ecosystem of Cherkasy

Introduction . There is a great deal of researches on the effects of S. canadensis L. on species of phytocenoses and biodiversity in general, however the results of such researches have many contradictions. They differ depending on their research locations . This proves that the behavior of S. canadensis L. in phytocenoses is highly dependent on many factors (soil, climate, species composition of local phytocenoses ) as well as the lack of a clear understanding of the mechanisms of its impact on phytocenoses, indicating the need to further study the impact of this species on phytocenoses to understand this mechanism. Purpose. The detection of S. canadensis L . localities in the Cherkasy urban ecosystem, study of synecological parameters of S. canadensis L. and accompanying species, as well as its influence on the floristic composition of phytocenoses; predicting the possibility of further increasing the invasion area and identifying priority areas for measures to control it. Methods. Locations were searched using the route method. The accounting was carried out at accounting sites of 1 m 2 , using standard geobotanical techniques. Statistical processing of the results was performed using dispersion coefficient, diversity compositioт coefficient, occurrence coefficient, Jaccard similarity coefficient and cluster analysis by nearest neighbor method. Results. In the course of the research conducted during the vegetation period 2016-2017, a significant level of presence of the S. canadensis L . was noted in 9 districts in Cherkasy: average projective coverage of 20,00% - 82 , 67%. S. canadensis L . dominates on 74% of the accounting sites. In all districts depletion of the species composition of spontaneous plant communities due to the invasion of the S. canadensis L. was found: the average number of species per 1 m 2 was 6.68 ± 0.23 species. The occurrence coefficients of the accompanying species are calculated, the species occurring in phytocenoses with S. canadensis L . are most often identified: Elymus repens (L.) Gould (76%) Ambrosia artemisiifolia L . (64%) Achillea submillefolium Klok. et Krytzka (50%) Stenactis annua (L.) Cass. ex Less. (36%) Acer negundo L. (30%) Sonchus arvensis L. (26%) Poa trivialis L . (20%) Trifolium pratense L . (18%) Artemisia absinthium L. (16%) Trifolium arvense L . (16%), Artemisia vulgaris L. (14%). In comparing the species composition of the phytocenoses of the 9 districts by Jaccard similarity coefficient and the cluster analysis of the average projective coverage of the S. canadensis L. and accompanying species, priority areas were identified to control the invasion of the S. canadensis L . Combining cluster analysis with Jaccard similarity coefficient increases the accuracy of the results (because the species composition of the phytocenoses in addition to their quantitative indicators is taken into account). Similar invasion behavior is predicted in areas with similar species composition of phytocenoses. Conclusion. S. canadensis L . was detected in 9 Cherkasy districts. Negative influence of the S. canadensis L . on the species composition of phytocenoses has been proved. The species that were found most often with the S. canadensis L . have adapted to the conditions it creates. The combination of Jaccard similarity coefficient and cluster analysis yields more accurate results than cluster analysis alone.