Freshwater snails Gyraulus parvus (Say, 1817) and G. laevis (Alder, 1838): a story of the invasion at the population level

ŠLACHTOVÁ, Erika, Luboš BERAN, Markéta NOVÁKOVÁ, Veronika HORSÁKOVÁ, Rowson BEN, Jaroslav HLAVÁČ, Jeffrey Clark NEKOLA and Michal HORSÁK. Freshwater snails Gyraulus parvus (Say, 1817) and G. laevis (Alder, 1838): a story of the invasion at the population level. In 9th European congress of malacological societies (Euromal 2021). 2021.

Basic information

• Original name: Freshwater snails Gyraulus parvus (Say, 1817) and G. laevis (Alder, 1838): a story of the invasion at the population level
• Authors: ŠLACHTOVÁ, Erika, Luboš BERAN, Markéta NOVÁKOVÁ, Veronika HORSÁKOVÁ, Rowson BEN, Jaroslav HLAVÁČ, Jeffrey Clark NEKOLA and Michal HORSÁK.
• Edition: 9th European congress of malacological societies (Euromal 2021), 2021.

Other information

• Original language: English
• Type of outcome: Presentations at conferences
• Confidentiality degree: is not subject to a state or trade secret
• Tags: International impact

Abstract

Most of the non-native gastropods in European inland waters have originated from North America. The planorbid snail Gyraulus parvus is one of these species, being firstly reported from Germany in the 1970s. It has since spread across Central and Western Europe mostly in artificial and highly modified habitats. However, considerable conchological and anatomical similarity exists between it and the native European G. laevis, mainly occupying mesotrophic pools and wetlands. Using four other European and one North American Gyraulus species as outgroups, separate phylogenetic analyses based on mitochondrial and nuclear DNA sequence showed that G. parvus and G. laevis are in fact part of the same species-level clade, with G. parvus having nomenclatural priority. Moreover, the structure within the mitochondrial tree suggests the North American origin of the invasive populations spreading in Europe even in countries where G. parvus has not yet been recorded, such as the United Kingdom. Although native and non-native races in Europe tend to possess some differences in conchology and ecology, the degree of overlap makes it impossible to accurately distinguish between them without the DNA barcode. Our findings change the conservation view on the rare native European race. While interspecific competition among freshwater mollusc species is rare, the invasion on an intraspecific level may represent a serious threat for native populations. Additionally, the spreading of the non-native race of G. parvus from North America increases the risk of introducing non-native trematodes as this exotic race is a very common intermediate host of many schistosomes.