Report of Heptapleurum arboricola naturalising in Sicily (IT)
Heptapleurum arboricola (synonym: Schefflera arboricola: Araliaceae) is native to China and Taiwan where it grows in forests and along riverbanks below altitudes of 900 m. It is considered to be invasive in the United States (Hawaii and Florida), the Fiji Islands, Singapore and Brazil. Where the species is invasive, birds have been reported as spreading the species via the consumption of seeds. S. arboricola has been recorded as naturalized in the EPPO region in the Canary Islands (Spain) and Turkey. The species was introduced into the EPPO region approximately 100 years ago via Kew Gardens (GB). Since then it has been widely utilised as an ornamental species in gardens. In 2017, three self-sown seedlings of H. arboricola were observed in urban areas at Castellammare del Golfo, on the north-west coast of Sicily (IT). These plants were observed growing from cracks in the pavement and no other specimens were found in the surrounding area. Climate is likely to be a limiting factor for the establishment of H. arboricola in the natural environment in the Mediterranean area of the EPPO region. The species requires high levels of rainfall and humidity: the annual rainfall where the species was observed in Italy is only half the minimum annual rainfall (≈ 1 600 mm) where the species is regarded as invasive. The authors of the current study suggest that H. arboricola should be monitored to ensure the species does not establish in the Mediterranean region.
Sources
Badalamenti E (2021) First record of Heptapleurum arboricola Hayata (Araliaceae) as a casual non-native woody plant in the Mediterranean area. BioInvasions Records 10 (in press).