Sliders
Set the below variable values to see predictions of several response variables shown in the bar graph.
Description of the models can be found at the bottom of each page.
Desciption of models and variables:
A suite of predictor variables, measured in field, were assessed for their correlation to invertebrate and periphyton biomass, using general linear models (GLMs) compared using Akaike’s Information Criterion corrected for small sample sizes. The variables we included in the final models are represented as sliders above.
Sliders:
Periphyton density (μg cm⁻²): The density of algae, microbes, bacteria, and detritus attached to substrate.
Ephemeroptera, Plecoptera, and Trichoptera density (g m⁻²): The density of invertebrates on the families Ephemeroptera, Plecoptera, and Trichoptera.
Predicted values:
Invertebrate density (g cm⁻²): The density of all invertebrates predicted to occur based on GLMs.
Periphyton density (μg cm⁻²): The density of algae, microbes, bacteria, and detritus attached to substrate, predicted to occur based on GLMs.
Citation: …
Desciption of models and variables:
Gravel size is important to the Atlantic Salmon spawning; too fine or too coarse, and the salmon will either not spawn or have poor egg survival (Purchase 2018).
D50 Gravel size: was predicted based on the following calculations (Wilkins & Snyder 2011)
D50 = 𝛕b / (𝛒s - 𝛒) * g * 𝛕*
Parameters:
𝛕b = 𝛒 * g * n3/5 * [Q/W]3/5 * S7/10
𝛒 = density of water = 1000 kg/m3
g = acceleration by gravity = 9.80665 m/s2
n = channel roughness coefficient = n = 0.04 as estimate for gravel bed rivers from Barnes 1967
𝛒s = sediment density = 2650 kg/m3
* = Shields parameter = 0.04 to follow Wilkins & Snyder 2011
Variables to retreive from HydroSHEDs:
S = channel gradient, Calculated as the ratio between the elevation drop within the river reach (i.e. the difference between min. and max. elevation along the reach) and the length of the reach.
Q = Discharge (m3/s), Average long-term discharge estimate for river reach, in cubic meters per second.
W = channel width (m), Calculated as the surface river area of the river reach segment divided by length of the river reach segment.
Spawning suitability: in predicted gravel size for fish of chosen length (m) calculated using the following equation:
Suitability = e((-1/2) * ((D50 - ideal.fish.gravel)/8)2)
Ideal.fish.gravel = 109 * (1.26fish.length - 1)
This equation associates a higher probability of spawning in larger gravel for longer fish, and a higher probability of spawning in smaller gravel for smaller fish.
Assumes the ideal spawning gravel for a fish of 2m is 64 mm, for a fish of 1 m is 32 mm, for a fish of 0 m is 16 mm etc, with a bell shaped distribution of suitability around the ideal gravel size with a standard deviation of 8. If D50 is lower than 16 or higher than 64, the suitability is 0.
Citations:
Barnes, H. 1967. Roughness Characteristics of Natural Channels. United States Geological Survey: Publications.
Linke, S., Lehner, B., Ouellet Dallaire, C., Ariwi, J., Grill, G., Anand, M., Beames, P., Burchard-Levine, V., Maxwell, S., Moidu, H., Tan, F., Thieme, M. (2019). Global hydro-environmental sub-basin and river reach characteristics at high spatial resolution. Scientific Data 6: 283. doi: https://doi.org/10.1038/s41597-019-0300-6
Lehner, B., Messager, M.L., Korver, M.C., Linke, S. (2022). Global hydro-environmental lake characteristics at high spatial resolution. Scientific Data 9: 351. doi: https://doi.org/10.1038/s41597-022-01425-z
Purchase, C. (2018). A systematic review on the effectiveness of salmonid spawning habitat improvements, and recommendations to potentially increase productivity of depressed Newfoundland Atlantic salmon (Salmo salar) populations.
Wilkins, and Snyder. 2011. Geomorphic comparison of two Atlantic coastal rivers: Toward an understanding of physical controls on Atlantic salmon habitat. River Research and Applications.
D50 = 𝛕b / (𝛒s - 𝛒) * g * 𝛕*
Parameters:
𝛕b = 𝛒 * g * n3/5 * [Q/W]3/5 * S7/10
𝛒 = density of water = 1000 kg/m3
g = acceleration by gravity = 9.80665 m/s2
n = channel roughness coefficient = n = 0.04 as estimate for gravel bed rivers from Barnes 1967
𝛒s = sediment density = 2650 kg/m3
* = Shields parameter = 0.04 to follow Wilkins & Snyder 2011
Variables to retreive from HydroSHEDs:
S = channel gradient, Calculated as the ratio between the elevation drop within the river reach (i.e. the difference between min. and max. elevation along the reach) and the length of the reach.
Q = Discharge (m3/s), Average long-term discharge estimate for river reach, in cubic meters per second.
W = channel width (m), Calculated as the surface river area of the river reach segment divided by length of the river reach segment.
Spawning suitability: in predicted gravel size for fish of chosen length (m) calculated using the following equation:
Suitability = e((-1/2) * ((D50 - ideal.fish.gravel)/8)2)
Ideal.fish.gravel = 109 * (1.26fish.length - 1)
This equation associates a higher probability of spawning in larger gravel for longer fish, and a higher probability of spawning in smaller gravel for smaller fish.
Assumes the ideal spawning gravel for a fish of 2m is 64 mm, for a fish of 1 m is 32 mm, for a fish of 0 m is 16 mm etc, with a bell shaped distribution of suitability around the ideal gravel size with a standard deviation of 8. If D50 is lower than 16 or higher than 64, the suitability is 0.
Citations:
Barnes, H. 1967. Roughness Characteristics of Natural Channels. United States Geological Survey: Publications.
Linke, S., Lehner, B., Ouellet Dallaire, C., Ariwi, J., Grill, G., Anand, M., Beames, P., Burchard-Levine, V., Maxwell, S., Moidu, H., Tan, F., Thieme, M. (2019). Global hydro-environmental sub-basin and river reach characteristics at high spatial resolution. Scientific Data 6: 283. doi: https://doi.org/10.1038/s41597-019-0300-6
Lehner, B., Messager, M.L., Korver, M.C., Linke, S. (2022). Global hydro-environmental lake characteristics at high spatial resolution. Scientific Data 9: 351. doi: https://doi.org/10.1038/s41597-022-01425-z
Purchase, C. (2018). A systematic review on the effectiveness of salmonid spawning habitat improvements, and recommendations to potentially increase productivity of depressed Newfoundland Atlantic salmon (Salmo salar) populations.
Wilkins, and Snyder. 2011. Geomorphic comparison of two Atlantic coastal rivers: Toward an understanding of physical controls on Atlantic salmon habitat. River Research and Applications.