The New Zealand mud snail (Potamopyrgus antipodarum): autecology and management of a global invader.
The New Zealand mud snail (Potamopyrgus antipodarum; NZMS) is among the most globally widespread aquatic invaders, occurring in 39 countries and 5 continents. Herein we provide a systematic review of 245 articles, focusing on the ecological impacts, spatial distribution, population dynamics, vectors of spread, and management of invasive NZMS. Most NZMS introductions originate from already-established invasive populations, which represent a small number of clonal lineages. The invasion success of NZMS stems from opportunistic traits, and while their tolerance of broad ranges of environmental conditions facilitates spread, optimal conditions for successful NZMS establishment are evident: stable hydrology, slow water velocity, high specific conductivity, and moderate salinity. NZMS can become exceptionally abundant, driving the greatest secondary-production rates reported for any stream invertebrate. However, NZMS populations fluctuate seasonally and over longer time scales, with marked declines observed after population booms. Minimal genetic variation within and among invasive populations and minimal incidences of predation/parasitism suggest that environmental factors constrain populations. As detritivore-herbivores, NZMS impact multiple compartments of aquatic ecosystems and their functioning. NZMS alter invertebrate and algal communities and can resist digestion by many fish species, reducing fish condition. This lack of digestion combined with expanding NZMS populations suggest that snail-eating fish are unlikely to regulate NZMS populations and may aid in local range expansion. Management programs and technologies have recently emerged to assist resource managers, including advances in environmental DNA detection methods and effective chemical decontamination treatments. The objective of this review is to contribute to a more robust understanding of the global NZMS invasion, such that undesired impacts can be minimized or averted.