Global ecological impacts of invasive species in aquatic ecosystems

Abstract

The introduction of invasive species, which often differ functionally from the components of the recipient community, generates ecological impacts that propagate along the food web. This review aims to determine how consistent the impacts of aquatic invasions are across taxa and habitats. To that end, we present a global meta-analysis from 151 publications (733 cases), covering a wide range of invaders (primary producers, filter collectors, omnivores and predators), resident aquatic community components (macrophytes, phytoplankton, zooplankton, benthic invertebrates and fish) and habitats (rivers, lakes and estuaries). Our synthesis suggests a strong negative influence of invasive species on the abundance of aquatic communities, particularly macrophytes, zooplankton and fish. In contrast, there was no general evidence for a decrease in species diversity in invaded habitats, suggesting a time lag between rapid abundance changes and local extinctions. Invaded habitats showed increased water turbidity, nitrogen and organic matter concentration, which are related to the capacity of invaders to transform habitats and increase eutrophication. The expansion of invasive macrophytes caused the largest decrease in fish abundance, the filtering activity of filter collectors depleted planktonic communities, omnivores (including both facultative and obligate herbivores) were responsible for the greatest decline in macrophyte abundance, and benthic invertebrates were most negatively affected by the introduction of new predators. These impacts were relatively consistent across habitats and experimental approaches. Based on our results, we propose a framework of positive and negative links between invasive species at four trophic positions and the five different components of recipient communities. This framework incorporates both direct biotic interactions (predation, competition, grazing) and indirect changes to the water physicochemical conditions mediated by invaders (habitat alteration). Considering the strong trophic links that characterize aquatic ecosystems, this framework is relevant to anticipate the far-reaching consequences of biological invasions on the structure and functionality of aquatic ecosystems.

An invasion risk map for non-native aquatic macrophytes of the Iberian Peninsula

“…Some freshwater systems are considered biodiversity hotspots (Murphy, 2002;Strayer & Dudgeon, 2010;Brundu, 2015;Serrano & Díaz Paniagua, 2015) and are one of the most threatened ecosystems in the world (Collen & al., 2014;Brundu, 2015;Serrano & Díaz Paniagua, 2015). These systems are particularly susceptible to biological invasions, because of their propensity to shift away from natural conditions and feedbacks that alter colonized habitats (Willby, 2007;Aguiar & Ferreira, 2013;Brundu, 2015;Gallardo & al., 2015). Aquatic macrophytes play an important role in the structure and function of freshwater systems (Chambers & al., 2008;García-Murillo & Fernández-Zamudio, 2015) by providing a structurally complex environment (Rennie & Jackson, 2005;Dibble & al., 2006).…”

Small size today, aquarium dumping tomorrow: sales of juvenile non-native large fish as an important threat in Brazil

“…As preventive measure, we recommend stringent control on the trade of giant arapaima and peacock basses. Top-predators have great potential to negatively affect the abundance of native biota and cause the extirpations of benthic invertebrates and fish (Gallardo et al, 2016).…”

Revisiting recent history: records of occurrence and expansion of the European green crab across Prince Edward Island, Atlantic Canada

“…This has been, in part, attributed to a sharp increase in global shipping, the use of ballast water since early in the nineteenth century, and the ability of species with free-swimming larvae to invade numerous shorelines (Carlton 1996;Ruiz et al 1997;Seebens et al 2013). Many of these species are crustaceans and mollusks, which together comprise nearly half of known marine invaders, including some with wide distributions and pronounced ecological impacts (Grosholz and Ruiz 1996;Cohen and Carlton 1997;Bax et al 2003;Gallardo et al 2016). Unfortunately, most studies on invasive species have focused on their spread across oceans and continents, often dismissing expansion patterns taking place more locally inside the boundaries of particular regions (e.g.…”