Attributes and effects of the invasive air-breathing freshwater snail Physa acuta on ecosystem properties and services

Abstract

Context. Freshwater ecosystems can experience significant disturbance from the introduction of non-native species. The sewage snail (SWGS), Physa acuta, has invaded numerous countries globally; however, a comprehensive assessment of its impacts is still lacking. Aims. Our objective was to qualitatively and quantitatively assess the impacts of SWGS on ecosystem services. Methods. The impacts of this invasive snail were synthesised from 135 references retrieved from the literature. The frequency of positive and negative effects on ecosystem services was compared using Fisher’s exact test. Key results. The number of negative effects of SWGS was higher than the positive effects on cultural services (72 v. 28% respectively) and on provisioning services (67 v. 33% respectively). All effects on regulating and maintenance services were negative, which represents a statistically significant trend when compared with cultural and provisioning services. Conclusions. SWGS primarily exerts negative effects on ecosystem services. However, it also enhances certain provisioning services related to biodiversity (e.g. increasing number of ciliate species). Additionally, it contributes to cultural services such as health (e.g. bioindicator for heavy metals) and research (e.g. study model). Implications. Our study underscores the need for comprehensive assessments to evaluate the impact of invasive species on ecosystem services, offering valuable insights for informed management strategies.