Temporal Variation in the Importance of a Dominant Consumer to Stream Nutrient Cycling

Griffiths, Natalie A.; Hill, Walter R.

doi:10.1007/s10021-014-9785-1

Cited by 16 publications

(18 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Of all taxa surveyed, salmonids had among the lowest per capita SRP excretion rates along with Cottidae, suggesting a dietary P limitation, as nutrient availability must meet the assimilatory demands of the consumer (McManamay et al 2010). Griffiths and Hill (2014) found similar results where another aquatic snail species (Elimia clavaeformis) accounted for an average of 58% of stream water ammonium concentrations yet supplied only 1% of SRP concentrations. This dichotomy between NH 4 + -N and SRP excretion has been previously observed.…”

Section: Discussionsupporting

confidence: 57%

Nonnative fish stocking alters stream ecosystem nutrient dynamics

Alexiades

Flecker

Kraft

2017

Ecological Applications

View full text Add to dashboard Cite

Each year, millions of hatchery-raised fish are stocked into streams and rivers worldwide, yet the effects of hatchery-raised fish on stream nutrient cycles have seldom been examined. We quantified the influence of supplemental nonnative fish stocking, a widespread recreational fishery management practice, on in-stream nutrient storage and cycling. We predicted that supplemental, hatchery-raised brown trout (Salmo trutta) stocking would result in increased N and P supply relative to in-stream biotic demand for those nutrients and that stocked fishes would remineralize and store a significantly greater amount of N and P than the native fish community, due to higher areal biomass. To test these predictions, we measured the biomass, nutrient (NH -N and soluble reactive phosphorus [SRP]) remineralization rates, and body carbon, nitrogen, and phosphorus content of the native fish community and trout stocked into four study streams. We then estimated fish growth rates to determine species-specific nutrient sequestration rates in body tissues for both stocked and native fish and measured ammonium and phosphorus uptake rates to determine the relative influence of net fish nutrient remineralization on stream nutrient cycles. When brown trout were stocked in these systems at density levels that were orders of magnitude higher than ambient native fish density, they provided a sizeable source of NH -N that could account for up to 85% of demand for that nutrient. Stocked trout had minimal effects on in-stream SRP cycles even at high release densities, likely due to low per capita SRP excretion rates. A unique feature of our study was that we evaluated the temporal component of the stocked trout nutrient subsidy by estimating the number of fish removed from the system through natural mortality and angler harvest, which indicated that the stocked trout subsidy lasted approximately 6-8 weeks after stocking. By combining population models with areal nutrient excretion rates and estimates of biotic nutrient uptake, we showed that trout stocking provided a strong pulsed nutrient subsidy.

show abstract

Section: Discussionsupporting

confidence: 57%

Nonnative fish stocking alters stream ecosystem nutrient dynamics

Alexiades

Flecker

Kraft

2017

Ecological Applications

View full text Add to dashboard Cite

show abstract

“…Arrow widths are proportional to the square root of the flux rate. Winter = 22 Dec–22 Feb; spring = 23 Feb–13 Apr; summer = 20 Jun–23 Aug; autumn = 18 Oct–20 Dec. Heterotrophic nitrogen uptake in fall was estimated from whole stream ammonium uptake on 12 November 2012 (Griffiths & Hill, ); nitrogen standing crop associated with leaves was estimated from autumnal leaf biomass (Mulholland et al ., ) multiplied by biomass‐specific leaf nitrogen measured in this study.…”

Section: Resultsmentioning

confidence: 99%

“…Gross primary production (GPP) and ecosystem respiration (ER) were measured with a one‐station, open‐system diel approach (Roberts et al ., ; Griffiths & Hill, ). Metabolic rates were calculated from the rate of change in dissolved oxygen over time after accounting for reaeration.…”

Section: Methodsmentioning

confidence: 99%

“…Net primary production was estimated from GPP by assuming a photosynthetic quotient of 1 and an autotrophic respiration fraction of 0.43 determined for Walker Branch (Hall & Beaulieu, 2013). Heterotrophic nitrogen uptake by leaves was estimated from streambed ammonium uptake (21.6 mgN m À2 day À1 ) measured on 12 November 2012 (Griffiths & Hill, 2014). The standing crop of leaf nitrogen was estimated from the 536 g AFDM m À2 November standing crop reported by Mulholland et al (1985a) multiplied by the nitrogen content measured in the November leaf sample in this study.…”

Section: Areal Flux and Standing Crop Estimatesmentioning

confidence: 99%

“…Primary production in these streams is closely related to streambed irradiances, which vary dramatically with the annual cycle of leaf emergence and leaf abscission on streamside trees (Roberts, Mulholland & Hill, 2007). Nitrogen excretion by grazing snails is higher under open canopies than closed canopies (Moslemi et al, 2012), presumably because light-stimulated primary production provides greater biomass of nitrogen-containing algae for ingestion and assimilation (Griffiths & Hill, 2014). Consumer growth has also been correlated with streambed irradiances and primary production (e.g.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Nitrogen processing by grazers in a headwater stream: riparian connections

Hill

Griffiths

2016

Freshwater Biology

Self Cite

View full text Add to dashboard Cite

Summary Primary consumers play important roles in the cycling of nutrients in headwater streams, storing assimilated nutrients in growing tissue and recycling them through excretion. Although environmental conditions in most headwater streams and their surrounding terrestrial ecosystems vary considerably over the course of a year, relatively little is known about the effects of seasonality on consumer nutrient recycling these streams. In this study, we measured nitrogen accumulated through growth and excreted by the grazing snail Elimia clavaeformis (Pleuroceridae) over the course of 12 months in Walker Branch, identifying close connections between in‐stream nitrogen processing and seasonal changes in the surrounding forest. Nitrogen processing rates were positively correlated with ecosystem respiration, which was driven by leaf phenology on streamside trees. Snail nitrogen assimilation, growth and excretion were relatively high in spring before leaf emergence, low in summer when canopy shade was extensive and high again in autumn after leaf‐fall. During the time that snails grazed primarily on epilithon (winter, spring and summer), growth and excretion rates followed changes in light and epilithon biomass. In autumn, when snails primarily grazed fallen leaves, leaf‐associated microbes provided large subsidies of nitrogen for the snails. Nitrogen accumulation in snail biomass was greater in the 2 months following leaf‐fall than at any other time of the year. Snails were less important as nitrogen sinks than as sources of recycled nitrogen in Walker Branch. Over the course of the year, snails excreted approximately 12 times more nitrogen than they accumulated in biomass. Nitrogen accrued during growth in spring was subsequently lost in summer when primary production declined and snails underwent tissue loss. Catabolic losses represented >40% of the nitrogen excreted by the snails in summer. Net nitrogen growth efficiency (growth/assimilation), which varied with food availability, was only 8% for the entire year. Neither growth nor excretion was positively correlated with nitrogen concentrations in grazing substrata. Snails achieved high standing crops and were significant contributors to nitrogen spiralling in Walker Branch. On an areal basis, nitrogen in snail biomass (mgN m−2) was two to five times greater than that in epilithon biomass, depending on the season. Snails assimilated and excreted up to 50% of the nitrogen initially taken up by autotrophs and leaf microbes, and they were likely to have additional effects on nitrogen spiraling through egestion and the cropping of assimilative biomass. Primary consumers like Elimia are important catalysts of nutrient movement through headwater streams, decreasing residence times and facilitating fluxes to downstream waters.

show abstract

Using a space‐for‐time substitution approach to predict the effects of climate change on nutrient cycling in tropical island stream ecosystems

Frauendorf

MacKenzie

Tingley

et al. 2020

Limnology & Oceanography

View full text Add to dashboard Cite

Climate change is expected to alter precipitation patterns worldwide, which can have direct effects on streamflow dynamics. In many tropical regions, climate-driven changes in rainfall are predicted to decrease streamflow and increase flash flooding, but the implications of these changes for stream ecosystem function are poorly understood. We used a rainfall gradient on Hawaii Island that mimics projected changes in rainfall and streamflow in order to estimate how climate change affects nutrient recycling. We measured per-capita excretion (nitrogen, phosphorus) and egestion rates of three dominant taxa (shrimp, caddisfly, midge) in eight streams along the gradient for 3 years. We scaled these rates to the population and community levels and measured nitrogen and phosphorus demand of the ecosystem to estimate if the relative contribution of nutrients supplied by invertebrates changes along the gradient. Across all three taxa, population egestion and excretion rates declined by 10-fold in drier streams. These declines were driven by lower population density, rather than differences in per-capita rates. Under the current climate scenario, community excretion supplied up to 70% of the nitrogen demand, which was 10-fold lower with projected changes in rainfall. Conversely, community excretion supplied up to 5% of the phosphorus demand, which did not vary across the rainfall gradient. This difference indicates that climate change may exacerbate nitrogen limitations in tropical island streams, and change the balance of nitrogen and phosphorus dynamics. Our study also demonstrates that space-for-time substitutions are a valuable tool to examine implications of climate change on ecosystem function in freshwater systems.

show abstract

Temporal Variation in the Importance of a Dominant Consumer to Stream Nutrient Cycling

Cited by 16 publications

References 61 publications

Nonnative fish stocking alters stream ecosystem nutrient dynamics

Nonnative fish stocking alters stream ecosystem nutrient dynamics

Nitrogen processing by grazers in a headwater stream: riparian connections

Using a space‐for‐time substitution approach to predict the effects of climate change on nutrient cycling in tropical island stream ecosystems

Contact Info

Product

Resources

About