A review of the reported and future potential ecological impacts of the invasive freshwater snail Tarebia granifera in South Africa.

Abstract

The Southeast Asian gastropod Tarebia granifera is an invasive freshwater snail across several continents. Our review summarises the impacts of this invasive snail on invaded aquatic ecosystems. The most important impacts are those related to their ability to reproduce quickly and reach high densities within invaded ecosystems. The snail has reportedly caused declines and local extinctions in native snail populations globally. They can further significantly reduce algal standing stocks and may have severe impacts on benthic biomass, resulting in decreased benthic biodiversity and disturbances in aquatic ecosystem function. These invasive snails also cause bioturbation that can lead to changes in the nutrient cycles of invaded aquatic ecosystems and affect food web dynamics, with unknown implications for ecosystem function. Furthermore, T. granifera is well known to harbour a diverse range of parasitic species of medical and veterinary importance both within and outside their native ranges. The effective control of invasive T. granifera remains challenging as they are not easily preyed upon, and potential control methods may have unintentional side effects on native biota. This review provides evidence that there is a need to control this invader to avoid further degradation of freshwater habitats and aquatic biodiversity.