RANUNCULUS ACRIS (RANUNCULACEAE), A POTENTIALLY INVASIVE SPECIES: CONFIRMATION OF ITS PRESENCE IN ARGENTINA AND NATURALIZATION IN TIERRA DEL FUEGO

Background and aims: The European Ranunculus acris is an invasive species in the world, and has been reported for the Northeast and South of Argentina. However, its presence is not conclusive, and it is not mentioned in recent floras of the country. The objective of the work is to confirm the presence of the species R. acris in Argentina and its naturalization in Tierra del Fuego. In addition, it is proposed to analyze its morphology and its potential invasive behavior in the new environment. M&M: Herbarium specimens of R. acris and other species of the genus Ranunculus, and populations in its natural environment, in anthropized areas of the city of Ushuaia and surrounding areas, Tierra del Fuego, were studied. The morphology was comparatively analyzed and the taxonomic identity was established based on the type material, and previous descriptions and keys. To study the invasive potential of R. acris, an invasion risk matrix and specialized literature were used. Results: The presence of R. acris is confirmed for Argentina, expanding its range of distribution in the extreme south of the country, and it is recognized as naturalized in Tierra del Fuego. Based on the morphological analysis, glabrous receptacle, erect habit and deeply lobed leaves were identified as characters of taxonomic value. According to the analysis of the invasion risk matrix, it is established that R. acris has a high invasive potential. Conclusion: Ranunculus species for Tierra del Fuego increase by nine, two of them being exotic. The possibility of eliminating naturalized populations of R. acris in the extreme South of Argentina should be evaluated due to its high invasive potential.