First report of Sphaeralcea bonariensis in Italy and the Mediterranean region
Sphaeralcea bonariensis (Malvaceae) is native to South America (Argentina, Bolivia, Chile, Paraguay, and Uruguay) where it is often described as behaving as a weed in arable lands, and ruderal habitats. It has been reported as an invasive species in South Africa, Brazil and the United Arab Emirates. Within the EPPO region, the species has been recorded from Belgium where it is considered a casual species. During floral surveys of Western Sicily (Italy) a few individuals of Sphaeralcea bonariensis were recorded near the village of Rocca Palumba (Palermo). Approximately ten plants were observed growing in Opuntia ficus-indica groves. These plants were at an altitude of 335 m a.s.l. and characterized by clay soils. This is the first time that S. bonariensis is reported from Italy, and it is also a first record for the Mediterranean region. The likely pathway for introduction is accidental through the contamination of compost or batches of seeds intended for agricultural use. Alternatively, S. bonariensis occurrence may be linked to the railway occurring in the immediate vicinity of the agricultural land. The pathway horticulture can be excluded, as the species is not used for this purpose in Italy. S. bonariensis should be considered as a casual alien plant in Italy. Further spread of the species should be avoided.
Sources
Aleo M, Cambria S, Minissale P, Bazan G (2022) First record of Sphaeralcea bonariensis (Cav.) Griseb. (Malvaceae) as a casual alien species in the Mediterranean area. BioInvasions Records 11(2), 338–344.