Supporting decision-making for improving longitudinal connectivity for diadromous and potamodromous fishes in complex catchments

Brevé, Niels; Buijse, A.D.; Kroes, Martin J.; Wanningen, Herman; Vriese, F. T.

doi:10.1016/j.scitotenv.2014.07.043

Cited by 34 publications

(25 citation statements)

References 48 publications

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“…>100 km; e.g. Salmo salar, Linnaeus 1758; Brevé, Buijse, Kroes, Wanningen, & Vriese, 2014). Nonetheless, other groups have also been affected by the presence of barriers such as mammals (Pavanato et al, 2016), macroinvertebrates (Cortes, Ferreira, Oliveira, & Godinho, 1998), plants (Jansson, Nilsson, & Renöfält, 2000), and crustaceans (Miya & Hamano, 1988).…”

Section: Introductionmentioning

confidence: 99%

Effects of altered river network connectivity on the distribution of Salmo trutta: Insights from a metapopulation model

et al. 2019

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Network connectivity is a key feature of rivers that affects patterns and processes in lotic ecosystems. Few studies have considered how changes in river reach connectivity might affect ecosystem attributes at a whole river network scale. The use of population dynamics models of keystone species at a river network scale allows exploration of how the effects of altered natural connectivity patterns might propagate through a river network. In this study, we present a metapopulation model to estimate the spatial distribution of the population density of brown trout (Salmo trutta), an ecologically and socioeconomically important top predator, in a river network in northern Spain. The model accounts for the presence of barriers that limit longitudinal connectivity in upstream and downstream directions. The model estimates the spatial distribution of densities of three age‐classes (young‐of‐the‐year, juveniles, and adults) in all river reaches that make up the network based on topology, connectivity and population dynamics (e.g. age‐class specific mortality, spawning, age‐class dispersal, and spawning migration patterns). Seventy‐five percent of the modelled population densities fell within the 95% confidence intervals of the empirical data (84.6% for young‐of‐the‐year, 69.2% for juveniles, and 69.2% for adults) collected in 13 reaches. The simulated removal of all longitudinal barriers to migration in the river network (re‐naturalisation of the whole catchment) produced a modelled increase in brown trout density in the most downstream reaches of the river network and lowered fish densities in the upstream portion of the network when bias in juvenile and adult movement direction was assumed. Furthermore, the simulated removal of a single obstacle affected fish density even in distant tributaries. The proposed model is an appropriate tool for the evaluation of spatial patterns of brown trout density at a river network scale and for the assessment of the impact of altered connectivity. This might help simulate the results of management strategies regarding river connectivity and show where population decreases or increases could be expected, although empirical knowledge of overall trout movement in the studied river networks is required for drawing realistic scenarios.

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Section: Introductionmentioning

confidence: 99%

Effects of altered river network connectivity on the distribution of Salmo trutta: Insights from a metapopulation model

et al. 2019

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“…Earlier studies on river fragmentation did not include historical and catchment information on the level of individual fish species (Lehner et al, 2011;Nilsson et al, 2005) and were restricted to local and regional cases or included only a few species or species guilds (Baisez et al, 2011;Brevé, Buijse, Kroes, Wanningen, & Vriese, 2014;Nunn & Cowx, 2012;O'Hanley, 2011;Rincón, Solana-Gutiérrez, Alonso, Saura, & García de Jalón, 2017;Winter & Fredrich, 2003). Therefore, the aim of this study was to analyse the species and river specific consequences of river fragmentation on migratory fish on a European scale.…”

mentioning

confidence: 99%

Species and river specific effects of river fragmentation on European anadromous fish species

Puijenbroek

Buijse

Kraak

et al. 2018

River Research & Apps

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105

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Fragmentation is one of the major threats to riverine ecosystems and this is most explicitly expressed by the decline in numbers of migratory fish species. Yet each species has different migration requirements and their natural distribution can include several catchments with multiple dams. Hence, to prioritize candidate rivers for improving accessibility, differences between species and between catchments have to be taken into account. The aim of this study was therefore to analyse the species and river specific effects of river fragmentation on migratory fish on a European scale. The effect of river damming on migratory fish was quantified for all 16 European long‐ and mid‐distance anadromous species and for 33 large European rivers. The historical distribution was compared with the current upstream accessibility of the main river and the current distribution and population status of each species. The observed effects of reduced connectivity were further quantified using the Dendritic Connectivity Index for species and the Fragmentation Index for rivers. Our results showed that only very few rivers are still unaffected by dams in the main stem and that the few remaining viable migratory fish populations in Europe occur in these accessible rivers. Barriers were prioritized for making passable based on the potential accessibility gain and the number of benefitting species, showing that the main stems of the rivers Shannon and Nemunas are the best candidates. It was concluded that evaluating species and river specific effects of fragmentation strongly aids in prioritizing rivers for improving upstream accessibility.

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“…The rather low number of evaluable studies is in accordance with former findings (e.g., Bunt et al, ; Noonan, Grant, & Jackson, ; Pompeu, Agostinho, & Pelicice, ; Roscoe & Hinch, ). The vast majority of fish passes have never been evaluated and will never be evaluated, although thousands of fish passes exist worldwide and improving longitudinal connectivity is high on the river rehabilitation agenda, for example, in Germany (Kail & Wolter, ) and the Netherlands (Brevé et al, ),…”

Section: Data Collectionmentioning

confidence: 99%

“…The vast majority of fish passes have never been evaluated and will never be evaluated, although thousands of fish passes exist worldwide and improving longitudinal connectivity is high on the river rehabilitation agenda, for example, in Germany (Kail & Wolter, 2011) and the Netherlands (Brevé et al, 2014),…”

Section: Data Collectionmentioning

confidence: 99%

Fish passes design discharge requirements for successful operation

Wolter

Schomaker

2019

River Research & Apps

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Longitudinal connectivity is one of the prime issues addressed in river restoration our days. At the same time, mitigation of climate change impacts by modes of renewable energy increasingly puts pressure on the remaining free flowing river stretches for hydroelectricity production. At the site level, this trade‐off manifests in the negotiation of water for upstream and downstream fish passage versus losses for hydroelectricity production. This study has compiled and analysed 193 studies evaluating fish passes designed to provide upstream migration for all species and size classes of the respective river system. The overall assessment of functioning and discharge dedicated to fish pass maintenance, site, and river characters were provided by the studies. The main objective here was deriving general guidance for the minimum amount of water needed for fully functioning upstream fish passage in relation to river size. There was a significant correlation between functionality and design discharge of a fish pass. Fully functioning fish passes (N = 92) had median design discharge of 5% of the mean average discharge of the river, restrictedly functioning of 1.1% and not functioning of 0.22%. A power model could be derived of design discharge needs in relation to river discharge, which is inversely related to river size. In large rivers, a rather small share of mean discharge is sufficient, whereas in small rivers, it cannot be further downscaled due to dimensions. This model might provide first guidance in adjusting needs for both hydroelectricity generation and fish conservation in regulated rivers.

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Supporting decision-making for improving longitudinal connectivity for diadromous and potamodromous fishes in complex catchments

Cited by 34 publications

References 48 publications

Effects of altered river network connectivity on the distribution of Salmo trutta: Insights from a metapopulation model

Effects of altered river network connectivity on the distribution of Salmo trutta: Insights from a metapopulation model

Species and river specific effects of river fragmentation on European anadromous fish species

Fish passes design discharge requirements for successful operation

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