As the biosphere undergoes greater interconnectivity from globalization, problems associated with the movement of non-native species are increasingly prevalent. Non-native species can present a wide range of difficulties in areas where they are introduced, including issues associated with agriculture, ecosystem viability, disease, and the decline of endemic species. However, accounts of many non-native taxa are underrepresented in primary literature, and introduced ranges, habitat associations, and potential impacts of these groups are not well known. The recent synthesis of georeferenced locality data from large natural history collections, federal reports, and citizen science observations into easily accessible, digital databases allows widespread analyses of non-native species occurrence and dispersal. Here, we explore and analyze ranges and possible effects of non-native terrestrial gastropods in the contiguous United States. We accessed 460,778 gastropod records from the United States Geological Survey (USGS) database, Biodiversity Information Serving Our Nation (BISON), to better understand the temporal and spatial dispersal of these non-native terrestrial gastropods.
Results/Conclusions
We extracted approximately 170,000 records of terrestrial occurrences in the contiguous United States, with approximately 4% of these records (6,637 records) from non-native species. Native ranges from which non-native taxa have dispersed include Western Europe/Northern Africa (60.31%), Central America and the Caribbean (19.44%), and Asia (8.68%). We found that the common snail genera Helix (Western Europe/Northern Africa) and Bulimulus (Caribbean) represent 10.90% and 8.23% of non-native terrestrial species records, respectively. These genera are known agricultural pests and disease vectors, with the potential to negatively impact native ecosystem health and biodiversity. Additionally, we found the genus Helix widely distributed across the contiguous United States, with 36.93% of Helix species occurrences in Texas, 12.59% in California, and 6.36% in Ohio. Movements of non-native terrestrial gastropods can be attributed to a variety of biotic and abiotic dispersal methods, including the aquarium trade, urbanization, and extreme weather events. As global travel and interconnectivity continue to increase, it is crucial that dispersal mechanisms, as well as the native ranges and impacts of many understudied gastropod species, receive more study.