ID:
publications-2478
Type:
Peer reviewed articles
Year:
2021
Authors:
Peter E. Jones; Toby Champneys; Jessica Vevers; Luca Börger; Jon C. Svendsen; Sofia Consuegra; Joshua Jones; Carlos Garcia de Leaniz
Title:
Selective effects of small barriers on riverâresident fish
Venue/Journal:
Jones , P E , Champneys , T , Vevers , J , Börger , L , Svendsen , J C , Consuegra , S , Jones , J A H & Garcia de Leaniz , C 2021 , ' Selective effects of small barriers on river-resident fish ' , Journal of Applied Ecology , vol. 58 , no. 7 , pp. 1487-1498 . https://doi.org/10.1111/1365-2664.13875
DOI:
10.1111/1365-2664.13875
Research type:
AI & Machine Learning
Water System:
Uncategorized
Technical Focus:
Abstract:
Abstract Habitat fragmentation is a principal threat to biodiversity and artificial river barriers are a leading cause of the global decline in freshwater biota. Although the impact of barriers on diadromous fish is well established, impacts on riverâresident fish communities remain unclear, especially for lowâhead barriers. We examined the movement of five contrasting freshwater fish (topmouth gudgeon, European minnow, stone loach, bullhead and brown trout) in an experimental cascade mesocosm with seven pools separated by small vertical barriers. Passage rates differed significantly among species and increased with body size and sustained swimming speed (Usus), ranging from an average of 0.2 passes/hr in topmouth gudgeon to 3.4 passes/hr in brown trout. A randomâwalk simulation indicated that barriers can result in net downstream movement and shifts in community composition. Passage rates in brown trout were leptokurtic, that is, most individuals were relatively sedentary while a small proportion showed frequent movements. Upstream passage rates of brown trout increased with body length and boldness while fish with lower aerobic scope tended to move downstream. Passage rates showed significant individual repeatability in brown trout, independent of body size, indicating the potential for inâstream barriers to exert selective effects on fish populations. Our results show that barrier effects can be more complex than simply blocking fish passage, and that riverâresident fish can be impacted even by very small barriers. We show that fish passage depends on a wide range of morphological, physiological and behavioural drivers, and that barriers can exert selective effects on these traits and cause shifts in community composition. Policy implications. Barrier mitigation measures need to embrace interspecific and intraspecific variation in fish passage to avoid inadvertent artificial selection on fish communities. Given the high abundance of lowâhead structures in river systems worldwide, a paradigm shift is needed to recognise the subtle impacts of small barriers on freshwater biodiversity. Removal of small barriers or natureâlike fishways should allow better passage of the wider fish community compared to widely used salmonidâcentric fish passage options.
Link with Projects:
689682
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