Golden mussel (Limnoperna fortunei) survival during winter at the northern invasion front implies a potential high-latitude distribution

Abstract

Aim: Golden mussel Limnoperna fortunei is an invasive bivalve in many freshwater ecosystems in Asia and South America. Cold winter temperatures are expected to restrict its spread to high-latitude areas. Cold tolerance and potential distribution of this species remain largely unstudied because the most extensively studied populations occur in tropical and sub-tropical areas. We sought to investigate cold tolerance of golden mussels and to model their potential distribution at higher latitudes. Location: China, Global. Methods: We investigated overwintering survival of caged golden mussels in a reservoir located at the northern invasion front in north China. We then determined the lowest water temperature at which mussel filtering occurred in laboratory. Finally, we modelled relative environmental suitability globally based on Maximum Entropy using the species’ most updated occurrence records. Results: Golden mussels in a northern invasion front reservoir could survive over a course of 6 days at <1°C, or 41 days at <2°C, or 108 days at <5°C, with 27% survival overall. Caged mussels were inaccessible to local predators and reproduced, with the subsequent population size increasing in early summer by ~280%, representing a potential source population. Laboratory tests demonstrated that the lowest water temperature at which mussels could filter water was 5.5°C, and 50% of individuals became active when temperature rose to 7.5–8.0°C. Species distribution modelling illustrated a potential distribution of golden mussels at higher latitude than presently found. Models that considered updated high-latitude occurrence records predicted a significantly larger suitable area than currently exists, including near the lower Laurentian Great Lakes. Main conclusions: Our findings suggest enhanced cold tolerance of golden mussels and wider potential distribution than currently exists. We emphasize the importance of examining samples from invasion fronts when developing distribution predictions for spreading invasive species.