Soil biogeochemical responses to the deposition of anadromous fish carcasses in inland riparian forests of the Pacific Northwest, USA

The historic abundance of salmonids returning to natal streams of the inland Pacific Northwest, USA, may have constituted a major nutrient influx into these commonly oligotrophic ecosystems. Inland ecosystems tend to be warmer and dryer and more nutrient limited than coastal ecosystems; therefore, understanding how these inland conditions influence the soil biogeochemical responses to salmon carcass deposition in riparian forests is a vital step in appropriately mitigating for the loss of this nutrient subsidy. Deposition of salmon carcasses in central Idaho riparian forests resulted in a 480-fold increase in soil nitrogen (N), a sevenfold increase in dissolved organic carbon (C), and a fourfold increase in soil respired CO2, with significant biogeochemical responses persisting at one year after amendment. Despite these large increases in soil N and C, estimates of soil N and C loading only accounted for 31% and 16% of the fish carcass N and C, respectively. However, the magnitude and persistence of soil biogeochemical responses to the deposition of anadromous fish carcasses in central Idaho attests to the importance of this nutrient subsidy to inland riparian ecosystems of the Pacific Northwest.

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Regulating riparian forests for aquatic productivity in the Pacific Northwest, USA: addressing a paradox

Environmental Science and Pollution Research ◽

10.1007/s11356-015-5814-7 ◽

2015 ◽

Vol 23 (2) ◽

pp. 1149-1157 ◽

Cited By ~ 8

Author(s):

Michael Newton ◽

George Ice

Keyword(s):

Pacific Northwest ◽

Riparian Forests ◽

The Pacific ◽

Aquatic Productivity

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Soil and Douglas-fir (Pseudotsuga menziesii) foliar nitrogen responses to variable logging-debris retention and competing vegetation control in the Pacific Northwest

Canadian Journal of Forest Research ◽

10.1139/x09-188 ◽

2010 ◽

Vol 40 (2) ◽

pp. 254-264 ◽

Cited By ~ 9

Author(s):

Robert A. Slesak ◽

Timothy B. Harrington ◽

Stephen H. Schoenholtz

Keyword(s):

Pacific Northwest ◽

Pseudotsuga Menziesii ◽

Douglas Fir ◽

Soil N ◽

Vegetation Control ◽

Competing Vegetation ◽

Total Soil ◽

The Pacific ◽

N Acquisition ◽

Total Soil N

Experimental treatments of logging-debris retention (0%, 40%, or 80% surface coverage) and competing vegetation control (initial or annual applications) were installed at two sites in the Pacific Northwest following clearcutting Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) stands to assess short-term effects on tree N acquisition, soil N supply, and total soil N. Vegetation control treatments began in the first year after harvest, and logging-debris manipulations were installed 2 years after harvest. Annual vegetation control increased foliar N concentration and content in most years at both sites, which was associated with higher available soil N and increased soil water content. Logging-debris retention treatments had no detectable effect on any of the foliar variables or soil available N at either site. There were no treatment effects on total soil N at the site with relatively high soil N, but total soil N increased with logging-debris retention when annual vegetation control was applied at the site with a low initial soil N pool. Competing vegetation control is an effective means to increase tree N acquisition in the initial years after planting while maintaining soil N pools critical to soil quality. The effect of logging-debris retention on tree N acquisition appears to be limited during early years of stand development, but increased soil N with heavy debris retention at certain sites may be beneficial to tree growth in later years.

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Advances in Fisheries Bioengineering

Advances in Fisheries Bioengineering ◽

10.47886/9781934874028.ch11 ◽

2008 ◽

Keyword(s):

Pacific Northwest ◽

River Flow ◽

Fish Passage ◽

Anadromous Fish ◽

Hydroelectric Dams ◽

Dissolved Gas ◽

Site Specific ◽

Total Dissolved Gas ◽

The Pacific ◽

Fish Survival

<em>Abstract.</em>—Historically, spillways and sluiceways at hydroelectric dams were constructed as conduits for transporting excess river flow or debris with little focus on their potential for safe fish passage routes. In recent times, however, these conveyances are increasingly viewed as viable fish passage routes and are used to increase potential survival for the declining salmonid populations, particularly in the Pacific Northwest. However, spill is uneconomical and, with some spillway configurations, may cause potentially lethal levels of total dissolved gas (TDG) saturation in the river. Recent estimates (direct effects) of juvenile anadromous fish survival and condition after passing nonturbine exit routes at hydro dams have shown much variation (83–100% survival) depending upon site-specific hydraulic characteristics, trajectory of entrained fish, and obstructions in the flow path. Efforts are underway to modify spillways and bypasses at several hydroelectric dams to decrease TDG and eliminate and/or minimize fish injury.

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Century‐long stomatal density record of the nitrophyte, Rubus spectabilis L., from the Pacific Northwest indicates no effect of changing atmospheric carbon dioxide but a strong response to nutrient subsidy

Ecology and Evolution ◽

10.1002/ece3.8405 ◽

2021 ◽

Author(s):

Ron Ydenberg ◽

Ben Leyland ◽

Mark Hipfner ◽

Herbert H. T. Prins

Keyword(s):

Carbon Dioxide ◽

Pacific Northwest ◽

Atmospheric Carbon Dioxide ◽

Stomatal Density ◽

Strong Response ◽

The Pacific ◽

Nutrient Subsidy ◽

Atmospheric Carbon

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Fine-root decomposition and N dynamics in coniferous forests of the Pacific Northwest, U.S.A.

Canadian Journal of Forest Research ◽

10.1139/x01-202 ◽

2002 ◽

Vol 32 (2) ◽

pp. 320-331 ◽

Cited By ~ 75

Author(s):

Hua Chen ◽

Mark E Harmon ◽

Jay Sexton ◽

Becky Fasth

Keyword(s):

Pacific Northwest ◽

Fine Roots ◽

Fine Root ◽

Root Decomposition ◽

N Availability ◽

Soil N ◽

Decomposition Rates ◽

N Dynamics ◽

The Pacific ◽

Fine Root Decomposition

We examined the effects of species, initial substrate quality, and site differences (including temperature, precipitation, and soil N availability) on fine-root (<2 mm diameter) decomposition in litter bags and its N dynamics in Sitka spruce (Picea sitchensis (Bong) Carrière), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) forests in Oregon, U.S.A. Species significantly influenced fine-root mass loss during the first 2 years of decomposition. Over the same period, site differences had little impact on decomposition of fine roots. The percentage of initial mass remaining of decomposing fine roots fitted a single-exponential model. The decomposition rate constant (k) for all 15 species examined ranged from 0.172 year1 for Engelmann spruce (Picea engelmanni Parry ex Engelm.) to 0.386 year1 for Oregon ash (Fraxinus latifolia Benth.). Initial C quality indices (e.g., cellulose concentration, lignin concentration) of fine roots were correlated with fine-root decomposition rates. In contrast, initial N concentration and soil N availability were not correlated with fine-root decomposition rates. The rate of N released from decomposing roots was positively correlated with the initial N concentration of the fine roots. The data suggest that decomposing fine roots could release at least 20 kg N/ha annually in mature Douglas-fir forests of the Pacific Northwest.

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Marine nitrogen in central Idaho riparian forests: evidence from stable isotopes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f04-220 ◽

2005 ◽

Vol 62 (3) ◽

pp. 518-526 ◽

Cited By ~ 22

Author(s):

Akihiro Koyama ◽

Kathleen Kavanagh ◽

Andrew Robinson

Keyword(s):

Stable Isotopes ◽

Marine Ecosystems ◽

Riparian Forests ◽

Anadromous Fish ◽

Sharp Decline ◽

Foliar Nitrogen ◽

Nutrient Sources ◽

Streams And Rivers ◽

N Pool ◽

Central Idaho

Terrestrial and marine ecosystems are linked by the annual migration of salmonids. We examined the contribution of anadromous fish to foliar nitrogen (N) in central Idaho riparian forests where anadromous fish have been in sharp decline for approximately 30 years. To determine if the amount of N from anadromous fish carcasses can be assessed from conifer foliage, we fertilized seedlings with varying proportions of N from marine sources and analyzed their foliar 15N/14N ratio (δ15N). Also, to evaluate whether N obtained from marine sources was evident in riparian forests, we analyzed the δ15N of conifer foliage, above and below waterfalls, along historically salmon-bearing and non-salmon-bearing streams and rivers in central Idaho. In the seedling study, the amount of marine N was positively correlated with foliar δ15N. Furthermore, we determined that foliar δ15N values in riparian forests were explained by the historical occurrence of salmon. Foliar δ15N declined significantly from bankside to upslope trees in transects along salmon-bearing streams and rivers, whereas there was no significant gradient along transects perpendicular to non-salmon-bearing reaches. We therefore conclude that marine nutrient sources have historically contributed to the N pool in riparian conifer forests and marine N persisted following 30 years of severe populations declines.

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