During the recent BioBlitz mollusc specialist Adrian Sumner discovered an alien snail, Zonitoides arboreus, in the RBGE glasshouses. The diminutive snail, just 5mm across, lives as a wild species in North America and has been spread around the world accidentally with the movement of living plants.

The Garden has a plant quarantine facility and strict proceedures to avoid the accidental introduction of pests and diseases. Stephan Helfer, responsible for biosecurity at the garden, commented…

These days we are extremely vigilant in the search for unwanted hitchhikers on plants coming into our living collection. We can’t know when this snail arrived, but it has probably been here a long time as it is a widespread hothouse alien. In the last three years no unwanted organisms have been found on the living plants collected by Garden staff. This shows the high standards being applied by our plant collectors. Botanical research sometimes involves collecting living plants, but we must do all we can to avoid bringing in unwanted pests and diseases.

Although not a native, this snail is a new record for the area. Being small and not particularly easy to identify it is probably under recorded. The only other record of this species for Scotland is from Glasgow Botanics!

Alien snail, Zonitoides arboreus, found at RBGE during the BioBlitz on 21st June