Non‐native fishes and climate change: predicting species responses to warming temperatures in a temperate region

Abstract

Summary 1. Temperate regions with fish communities dominated by cold‐water species (physiological optima <20 °C) are vulnerable to the effects of warming temperatures caused by climate change, including displacement by non‐native cool‐water (physiological optima 20–28 °C) and warm‐water fishes (physiological optima >28 °C) that are able to establish and invade as the thermal constraints on the expression of their life history traits diminish. 2. England and Wales is a temperate region into which at least 38 freshwater fishes have been introduced, although 14 of these are no longer present. Of the remaining 24 species, some have persisted but failed to establish, some have established populations without becoming invasive and some have become invasive. The aim of the study was to predict the responses of these 24 non‐native fishes to the warming temperatures of England and Wales predicted under climate change in 2050. 3. The predictive use of climate‐matching models and an air and water temperature regression model suggested that there are six non‐native fishes currently persistent but not established in England and Wales whose establishment and subsequent invasion would benefit substantially from the predicted warming temperatures. These included the common carp Cyprinus carpio and European catfish Silurus glanis, fishes that also exert a relatively high propagule pressure through stocking to support angling and whose spatial distribution is currently increasing significantly, including in open systems. 4. The potential ecological impacts of the combined effects of warming temperatures, current spatial distribution and propagule pressure on the establishment and invasion of C. carpio and S. glanis were assessed. The ecological consequences of C. carpio invasion were assessed as potentially severe in England and Wales, with impacts likely to relate to habitat destruction, macrophyte loss and increased water turbidity. However, evidence of ecological impacts of S. glanis elsewhere in their introduced range was less clear and so their potential impacts in England and Wales remain uncertain.

Parasites of non-native freshwater fishes introduced into England and Wales suggest enemy release and parasite acquisition

“…By contrast, the following non-native fishes were omitted from the study to avoid confounding issues with their heavy use in aquaculture would have potentially exposed them to a range of anti-parasite treatments: common carp Cyprinus carpio, goldfish Carassius auratus, rainbow trout Oncorhynchus mykiss and ide Leuciscus idus. Indeed, should any of these species be sampled in the wild in England and Wales then there is high probability they originated from a fish-farm as there are, for example, few naturally recruiting populations of C. carpio and O. mykiss present (Fausch 2007;Britton et al 2010). In addition, the regulations on their releases into the wild in the countries are comparatively light compared with the species included in this study, with regulations concerning C. carpio and O. mykiss broadly similar to some native fishes.…”

Ecological impacts of invasive alien species along temperature gradients: testing the role of environmental matching

“…A few studies have shown that impacts of IAS are higher in the environmental conditions for which they are adapted (e.g., oxygen concentration [MacNeil et al 2004]; salinity [Alcaraz et al 2008]; conductivity [Kestrup and Ricciardi 2009]). However, assessments of how climate change can affect the consumptive per capita impact of IAS are lacking in comparison to investigations of how abundance and area occupied will be affected (Parker et al 1999, Hellmann et al 2008 Peterson 2003, Bomford et al 2010, Britton et al 2010, to our knowledge no such procedure has been applied to impact; measurements of functional and physiological responses along environmental gradients could be useful predictors of the consumptive impacts of established IAS on native communities. Here, we provide the first general test of the Environmental Matching Hypothesis by conducting a meta-analysis of published data to examine the importance of temperature in determining IAS impact levels.…”

Distribution of non-native brook trout (Salvelinus fontinalis) across Norwegian waterbodies – is it an invasive species?

“…Such cold-water species may be vulnerable to the effects of warming temperatures caused by climate change (cf. Britton et al 2010;Hulme 2017). In some streams in Nova Scotia, the population density of brook trout was strongly related to water temperature, as streams that had a summer water temperature of 19 o C or more contained either few or no brook trout (MacMillan et al 2008).…”

“…For the majority of non-native species, no quantitative information is available regarding the consequences of such introductions (Simberloff et al 2013). Brook trout is classified as a medium-risk species among nonnative freshwater fish (Copp et al 2009;Britton et al 2010). Our article describes the distribution of brook trout in Norwegian water bodies.…”