First published records of alien plants in Switzerland and the Canton of Ticino
Botanical surveys conducted in Switzerland between 2015 and 2019 identified five alien plant species growing in natural habitats. Salpichroa origanifolia (Solanaceae), Salvinia molesta (Salviniaceae: EPPO A2) and Soliva sessilis (Asteraceae) are recorded for the first time in Switzerland whereas Celastrus orbiculatus (Celastraceae) and Veronica cymbalaria (Plantaginaceae) are recorded for the first time in the Canton of Ticino.
Salpichroa origanifolia is a perennial woody plant with a climbing stem up to 3 m long. Native to South America, it has been introduced into Africa, North America, Australia and the EPPO region. In the latter, it is reported in Croatia, France, Ireland, Italy, Portugal, Spain and the United Kingdom. The first occurrence of the species in Switzerland was in Minusio where it grows on a grassy slope between a road and a lake. It covers an area of approximately 100 m² where it makes up 50 % of the vegetation in the area. In the Canary Islands and in Italy it is regarded as invasive as it is able to spread via seed which is abundantly produced.
Salvinia molesta is an aquatic floating plant, native to Brazil and has been reported from several EPPO countries (see https://gd.eppo.int/taxon/SAVMO/distribution). S. molesta can form dense mats which can reduce access to the water for recreation; interfere with various engineering structures such as weirs, block drains and cause flooding. In Switzerland, it has been reported from water bodies In Chiasso, Coldrerio, Novazzano and Breggia between 2018/19. Some herbarium specimens which are preserved at the Cantonal Museum of Natural History attest the presence of this species in Novazzano and Coldrerio already in the summers of 2009 and 2015.
Soliva sessilis is a low growing annual herbaceous species native to South America and considered invasive in Australia, North America and New Zealand. In the EPPO region, it is naturalised in France, Italy, Norway, Portugal, the United Kingdom and Spain, around coastal areas. In Switzerland, two populations were identified in 2018 and 2020 respectively: (1) close to Agno, in a meadow population approximately 100 m², and (2) Melano, in a camp site close to a lake.
Celastrus orbiculatus is native to Asia and is a fast-growing woody vine species native to East Asia (China, Central and North Japan, Korean Peninsula and Far East Russia). The species is invasive in North America. In the EPPO region, it is recorded as alien in a number of countries (see https://gd.eppo.int/taxon/CELOR/distribution). In the Canton of Ticino, C. orbiculatus was found in two locations: (1) in Orselina near a private garden in 2015, and (2) in Croglio growing in an alluvial forest close to the river Tresa in 2017. The latter individual was removed as a precautionary measure.
Veronica cymbalaria is an annual herbaceous plant which is native to the Mediterranean part of the EPPO region. It was first reported in Switzerland in the late 1990s and further observations have been made since then. One population was identified close to Lugano, along a footpath in 2019.
Sources
* Mangili S, Schoenenberger N, Selldor P, Sasu I, Haritz C, Borsari A, Marazzi B, Frey D (2020) Ticino floristic notes 2020: discovery of three new neophytes for Switzerland. Bulletin of the Ticino Society of Natural Sciences 108, 83-91.