Pacific Salmon, Nutrients, and the Dynamics of Freshwater and Riparian Ecosystems

Naiman, Robert J.; Bilby, Robert E.; Schindler, Daniel E.; Helfield, James M.

doi:10.1007/s10021-001-0083-3

Cited by 533 publications

(487 citation statements)

References 69 publications

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“…In this context, a subsidized assemblage is one for which the sampling scale does not encompass the spatial and temporal scale of the production that supports it [3,24]. Streams where anadromous salmon provide nutrient subsidies to local stream and riparian plant and animal communities provide an example of this concept [25,43]. In this example, when the scale of observation is the stream, the system is subsidized because the production-base for the nutrients that salmon bring to streams spans the ocean-basin scale at which salmon forage.…”

Section: Discussionmentioning

confidence: 99%

The paradox of inverted biomass pyramids in kelp forest fish communities

et al. 2016

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Theory predicts that bottom-heavy biomass pyramids or 'stacks' should predominate in real-world communities if trophic-level increases with body size (mean predator-to-prey mass ratio (PPMR) more than 1). However, recent research suggests that inverted biomass pyramids (IBPs) characterize relatively pristine reef fish communities. Here, we estimated the slope of a kelp forest fish community biomass spectrum from underwater visual surveys. The observed biomass spectrum slope is strongly positive, reflecting an IBP. This is incongruous with theory because this steep positive slope would only be expected if trophic position decreased with increasing body size (consumer-to-resource mass ratio, less than 1). We then used d 15 N signatures of fish muscle tissue to quantify the relationship between trophic position and body size and instead detected strong evidence for the opposite, with PPMR % 1650 (50% credible interval 280-12 000). The natural history of kelp forest reef fishes suggests that this paradox could arise from energetic subsidies in the form of movement of mobile consumers across habitats, and from seasonally pulsed production inputs at small body sizes. There were four to five times more biomass at large body sizes (1-2 kg) than would be expected in a closed steady-state community providing a measure of the magnitude of subsidies.

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Section: Discussionmentioning

confidence: 99%

The paradox of inverted biomass pyramids in kelp forest fish communities

et al. 2016

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“…Here, we provide the most comprehensive global synthesis of observed and potential effects from RoR hydropower on salmonid fishes. We focus our review on salmonid fishes because of their unique ecological, cultural, and economic importance (Naiman et al 2002) as well as their near-global distribution in coastal and inland rivers. Based on the unique characteristics of flow diversion created by RoR hydropower, we synthesized empirical peer-reviewed literature and expanded upon information from previous reviews to hypothesize three main pathways of effect (e.g., altered ecological mechanisms, linking causes to effects) by which RoR hydropower operations could impact salmonids: the reduction of flow in river reaches, the presence of low-head dams impounding rivers, and the creation of anthropogenic flow fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Run-of-River hydropower and salmonids: potential effects and perspective on future research

Gibeau

Connors

Palen

2017

Can. J. Fish. Aquat. Sci.

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Abstract:The spatial footprint of individual run-of-river (RoR) hydropower facilities is smaller than reservoir-storage hydroelectric projects and their impacts to aquatic ecosystems are often assumed to be negligible. However, these effects are poorly understood, especially for salmonids whose freshwater habitat often overlaps with RoR hydropower potential. Flow regulation for RoR hydropower is unique in how it influences the seasonality and magnitude of flow diversion and because low-head dams can be overtopped at high flows. Based on a review of the primary literature, we identified three pathways of effects by which RoR hydropower may influence salmonids: reduction of flow, presence of low-head dams impounding rivers, and anthropogenic flow fluctuations. We synthesized empirical evidence of effects of RoR hydropower on river ecosystems from 31 papers, of which only 10 explicitly considered salmonids. We identified key research gaps including impacts of extended low-flow periods, anthropogenic flow fluctuations, and cumulative effects of multiple RoR projects. Filling these gaps is necessary to help manage and conserve salmonid populations in the face of the growing global demand for small-scale hydropower.Résumé : L'empreinte spatiale individuelle des centrales hydroélectriques au fil de l'eau est moindre que celle des centrales hydroélectriques avec réservoirs de retenue et, en conséquence, leurs impacts sur les écosystèmes aquatiques sont souvent jugés négligeables. Par contre, leurs effets écologiques sont peu connus, particulièrement pour les salmonidés dont l'habitat en eau douce coïncide souvent avec le potentiel hydroélectrique des centrales au fil de l'eau. La régulation des eaux par les centrales au fil de l'eau se distingue par son influence sur la saisonnalité et l'ampleur de la déviation des eaux, et parce que les barrages de basse-chute peuvent être submergés lors des crues. À la lumière d'un examen des sources documentaires primaires, nous avons cerné trois voies principales par lesquelles la production d'électricité des centrales au fil de l'eau peut influencer les salmonidés, soit la réduction des débits, la présence de barrages de basse-chute sur les rivières et des fluctuations d'origine humaine des débits. Nous avons produit une synthèse des résultats empiriques de 31 études portant sur les effets de la production d'hydroélectricité des centrales au fil de l'eau sur les écosystèmes lentiques, dont seulement dix s'intéressaient explicitement aux salmonidés. Nous avons cerné d'importantes lacunes dans les connaissances actuelles, dont l'impact de périodes prolongées de faible débit, des fluctuations d'origine humaine des débits et des effets cumulatifs de plusieurs centrales au fil de l'eau. Il est nécessaire de combler ces lacunes pour soutenir la gestion et la conservation durables des populations de salmonidés dans un contexte de demande mondiale croissante pour la production d'hydroélectricité à petite échelle.

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“…Moreover, terrestrial-derived particulate OM can support secondary production in estuaries (Antonio et al 2010, Cole & Solo mon 2012, Dias et al 2014. Organic matter can also enter the estuaries as a result of marine intrusion or by fish migrations (Naiman et al 2002, Kohler et al 2012.…”

Section: Introductionmentioning

confidence: 99%

Estuarine consumers utilize marine, estuarine and terrestrial organic matter and provide connectivity among these food webs

Dias¹,

Morais²,

Cotter³

et al. 2016

Mar. Ecol. Prog. Ser.

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The flux of organic matter (OM) across ecosystem boundaries can influence estuarine food web dynamics and productivity. However, this process is seldom investigated taking into account all the adjacent ecosystems (e.g. ocean, river, land) and different hydrological settings (i.e. river discharge). Therefore, we aimed to quantify the contribution of autochthonous and allochthonous OM to the lower food web along the estuarine salinity gradient, under different river discharge conditions. The carbon (C) and nitrogen (N) stable isotope ratios of pelagic (zooplankton) and benthic (Corbicula fluminea) primary consumers indicated that they rely on a mixture of autochthonous and allochthonous OM, including terrestrial-derived OM. Unexpectedly, the highest contribution of terrestrial-derived OM to the estuarine food web was observed during a low river discharge period (up to 70%), that succeeded a large winter flood, showing that extreme weather events may produce prolonged effects on estuarine food webs. The contribution of marine-derived OM was higher during low river discharge periods (up to 88%) and was restricted to the seaward end of the estuary. Concomitantly, the contribution of phytoplankton to primary consumers was the highest observed (up to 91%). Further, both pelagic and benthic consumers also relied on benthic C (i.e. sediment OM and microphytobenthos). This study demonstrates that primary consumers enhance connectivity between estuarine ecosystems by utilizing subsidies of terrestrial and marine origin, and also between estuarine habitats through reliance on pelagic and benthic OM.

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Pacific Salmon, Nutrients, and the Dynamics of Freshwater and Riparian Ecosystems

Cited by 533 publications

References 69 publications

The paradox of inverted biomass pyramids in kelp forest fish communities

The paradox of inverted biomass pyramids in kelp forest fish communities

Run-of-River hydropower and salmonids: potential effects and perspective on future research

Estuarine consumers utilize marine, estuarine and terrestrial organic matter and provide connectivity among these food webs

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