Current status and distribution of alien land snails and slugs in Greece

Alien species, those that have been introduced on purpose or by accident to an ecosystem that they do not naturally occur, may cause serious damages to their new environment. So far, our knowledge of alien land snails and slugs in Greece is limited. We performed a literature survey and recorded all occurrences of alien terrestrial gastropod species in Greece and supplemented our effort with observations from the iNaturalist platform. In total, we documented 91 literature records and iNaturalist observations of at least 11 alien species of land snails and slugs recorded throughout Greece for the period 1973–2024. The documented alien species are: Allopeas gracile (Hutton, 1834), Paralaoma servilis (Shuttleworth, 1852), Gonyodiscus rotundatus (O.F. Müller, 1774), Lucilla singleyana (Pilsbry, 1889), Zonitoides arboreus (Say, 1817), Hawaiia minuscula (A. Binney, 1841), Polygyra cereolus (Megerle von Mühlfeld, 1818), Ambigolimax parvipenis Hutchinson, Reise & Schlitt, 2022, A. valentianus (A. Férussac, 1821), Boettgerilla pallens Simroth, 1912, and Deroceras invadens Reise, Hutchinson, Schunack & Schlitt, 2011. A systematic survey for alien terrestrial gastropods in Greece is pressing. Greenhouses, botanical gardens, cultivated land, plant nurseries, and heavily disturbed habitats should be the first sites for investigation. We propose the involvement of citizen scientists in the search for alien species in order to speed up the surveys and to collect data from geographically isolated sites such as the Greek islands. Our work is a contribution to the knowledge of alien species of Greece.