Nutrient Enrichment with Salmon Carcass Analogs in the Columbia River Basin, USA: A Stream Food Web Analysis

Kohler, Andre E.; Pearsons, Todd N.; Zendt, Joseph S.; Mesa, Matthew G.; Johnson, Christopher L.; Connolly, Patrick J.

doi:10.1080/00028487.2012.676380

Cited by 43 publications

(59 citation statements)

References 67 publications

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“…Direct consumption of analogs may also explain some of the variation in coho growth and isotopic enrichment, as analog fragments and adult salmon tissue and eggs are consumed by coho (Armstrong et al 2010, Cram et al 2011, Kohler et al 2012b). However, our diet analysis provided no evidence of direct consumption of analogs, although this may reflect the fact that coho diets were only sampled once and at a different time (day 45) than invertebrate flux (day 14)…”

Section: Methodsmentioning

confidence: 99%

“…Numerous studies have shown that concentrations of limiting nutrients increase following inputs of resource subsidies such as periodic inputs of seaweed to islands (e.g., Spiller et al 2010), salmon or carcass analogs to streams (Johnston et al 2004, Kohler et al 2012b or cicadas to terrestrial ecosystems (Yang 2004). Higher nutrient levels following these resource pulses sometimes translate into increased primary productivity (Johnston et al 2004, Yang 2004), but not always (Ambrose et al 2004, Verspoor et al 2010.…”

Section: Methodsmentioning

confidence: 99%

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Linking resource availability and habitat structure to stream organisms: an experimental and observational assessment

et al. 2014

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An experiment and a mark‐recapture field study of juvenile coho salmon (Oncorhynchus kisutch) were conducted to identify controls of key energy flow chains in river food webs. In the small‐scale experiment, we investigated the individual and interactive effects of physical habitat structure (PHS) as small wood and resource availability (tissue of adult Chinook salmon, O. tshawytscha) on nutrients, algae, invertebrates, and fish predators including juvenile coho. In the field, we quantified the effects of natural variation in prey availability (invertebrate drift biomass), PHS (wood), and local fish density on summer growth of juvenile coho across multiple stream reaches. Adding salmon tissue to experimental channels resulted in strong bottom‐up effects on select invertebrates including increased population biomass of chironomids and baetids, the numerically dominant invertebrates, and faster growth of juvenile coho. We link the enhanced growth of coho to chironomid productivity: for instance, adult chironomid flux was 4.3× higher and coho consumption of these animals 3× higher in salmon‐subsidized channels. PHS in experimental channels was associated with reduced algal biomass, potentially in response to increased invertebrate consumption, and invertebrate flux or export. The field study revealed coho growth was negatively related to PHS and total fish density and positively related to Diptera drift biomass; however, the effects of fish density and drift biomass on coho growth were relatively weak. The field study also indicated that prey resource availability and coho growth were associated with differences in canopy cover, with prey biomass and coho growth 2–4× higher in reaches receiving more sunlight. As in the experiment, coho in natural stream reaches predominantly fed on adult chironomids and other Diptera, indicating that these taxa and life‐stages are a key link between the benthic food web and mobile vertebrate predators. Our study showed that bottom‐up processes initiated by salmon subsidies and possibly light flux determined key trophic interactions in the Cedar River food web. Moreover, we speculate that PHS may modify some of these interactions indirectly through its effects on the movement of organisms through the environment.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Linking resource availability and habitat structure to stream organisms: an experimental and observational assessment

et al. 2014

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“…We chose these two materials because they are the most realistic mimics of material delivered by naturally spawning salmon including carbon (C), nitrogen (N), phosphorus (P), trace metals and other micronutrients, and because they are being used for nutrient mitigation projects elsewhere in the Columbia River basin (e.g., Compton et al 2006, Kohler et al 2012.…”

Section: Experimental Designmentioning

confidence: 99%

“…Subsequently, it is generally expected that an increase in biofilm production or standing crop would lead to bottom-up stimulation of invertebrate production, and ultimately increase food availability for juvenile fish (Claeson et al 2006). Indeed, studies have demonstrated that additions of salmon carcasses or other fish-derived materials for mitigation can increase standing crops of biofilms and invertebrates (Claeson et al 2006, Kohler et al 2012) and growth, production and body condition of resident salmonids (Wipfli et al 2004, Kohler et al 2012). Yet, in many of these experiments, it is unclear whether increases in fish and invertebrate production were due to direct (consumption of mitigation material) or indirect (nutrient stimulation of biofilm) pathways (Kiernan et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Nutrient additions to mitigate for loss of Pacific salmon: consequences for stream biofilm and nutrient dynamics

2014

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Abstract. Mitigation activities designed to supplement nutrient and organic matter inputs to streams experiencing decline or loss of Pacific salmon typically presuppose that an important pathway by which salmon nutrients are moved to fish (anadromous and/or resident) is via nutrient incorporation by biofilms and subsequent bottom-up stimulation of biofilm production, which is nutrient-limited in many ecosystems where salmon returns have declined. Our objective was to quantify the magnitude of nutrient incorporation and biofilm dynamics that underpin this indirect pathway in response to experimental additions of salmon carcasses and pelletized fish meal (a.k.a., salmon carcass analogs) to 500-m reaches of central Idaho streams over three years. Biofilm standing crops increased 2-8-fold and incorporated marinederived nutrients (measured using 15 N and 13 C) in the month following treatment, but these responses did not persist year-to-year. Biofilms were nitrogen (N) limited before treatments, and remained N limited in analog, but not carcass-treated reaches. Despite these biofilm responses, in the month following treatment total N load was equal to 33-47% of the N added to the treated reaches, and N spiraling measurements suggested that as much as 20%, but more likely 2-3% of added N was taken up by microbes. Design of biologically and cost-effective strategies for nutrient addition will require understanding the rates at which stream microbes take up nutrients and the downstream distance traveled by exported nutrients.

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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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Nutrient Enrichment with Salmon Carcass Analogs in the Columbia River Basin, USA: A Stream Food Web Analysis

Cited by 43 publications

References 67 publications

Linking resource availability and habitat structure to stream organisms: an experimental and observational assessment

Linking resource availability and habitat structure to stream organisms: an experimental and observational assessment

Nutrient additions to mitigate for loss of Pacific salmon: consequences for stream biofilm and nutrient dynamics

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

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