The influence of climate change on the ecological impacts of invasive alien species (IAS) remains understudied, with deoxygenation of aquatic environments often-overlooked as a consequence of climate change. Here, we therefore assessed how oxygen saturation affects the ecological impact of a predatory invasive fish, the Ponto-Caspian round goby (Neogobius melanostomus), relative to a co-occurring endangered European native analogue, the bullhead (Cottus gobio) experiencing decline in the presence of the IAS. In individual trials and mesocosms, we assessed the effect of high, medium and low (90%, 60% and 30%) oxygen saturation on: (1) functional responses (FRs) of the IAS and native, i.e. per capita feeding rates; (2) the impact on prey populations exerted; and (3) how combined impacts of both fishes change over invasion stages (Pre-invasion, Arrival, Replacement, Proliferation). Both species showed Type II potentially destabilising FRs, but at low oxygen saturation, the invader had a significantly higher feeding rate than the native. Relative Impact Potential, combining fish per capita effects and population abundances, revealed that low oxygen saturation exacerbates the high relative impact of the invader. The Relative Total Impact Potential (RTIP), modelling both consumer species’ impacts on prey populations in a system, was consistently higher at low oxygen saturation and especially high during invader Proliferation. In the mesocosm experiment, low oxygen lowered RTIP where both species were present, but again the IAS retained high relative impact during Replacement and Proliferation stages at low oxygen. We also found evidence of multiple predator effects, principally antagonism. We highlight the threat posed to native communities by IAS alongside climate-related stressors, but note that solutions may be available to remedy hypoxia and potentially mitigate impacts across invasion stages.
Bibliographical noteFunding Information:
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871081 (AQUACOSM) as well as financial support from the Regional Council of Ile-de-France under the DIM Program R2DS I-05-098/R and 2015-1657. It has received a support under the French program “Investissements d’Avenir” with the references ANR-10-EQPX-13-01 Planaqua and ANR-11-INBS-0001 AnaEE France. It has benefited from technical and human resources provided by CEREEP Ecotron IleDeFrance (CNRS/ENS UMS 3194), with JWED also supported by Inland Fisheries Ireland (IFI), RNC by the Alexander von Humboldt Foundation and Department for the Economy Northern Ireland, and NEC by Environmental Protection Agency (EPA). PRL thanks the Canada Research Chair program. Thanks also to the Natural Environment Research Council (NERC).
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Copyright 2021 Elsevier B.V., All rights reserved.
- Climate change
- Functional responses
- Invasive alien species
- Neogobius melanostomus
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics