Get mean trophic level of each species

Calculates the consumption-rate-weighted mean trophic level of each species, defined as $$ T_i = \frac{\int r_i(w)\,N_i(w)\,T_i(w)\,dw} {\int r_i(w)\,N_i(w)\,dw}, $$ where \(r_i(w) = (1 - f_i(w))\,E_i(w)\) is the consumption rate of an individual of species \(i\) at weight \(w\), \(N_i(w)\) is the abundance density, and \(T_i(w)\) is the size-resolved trophic level from getTrophicLevel(). As in getTrophicLevel(), the resource is given a size-dependent trophic level controlled by the w_R and beta_R arguments.

Usage

getTrophicLevelBySpecies(
  params,
  n = initialN(params),
  n_pp = initialNResource(params),
  n_other = initialNOther(params),
  w_R = 1e-10,
  beta_R = 1000,
  ...
)

Arguments

params

A MizerParams object.

n

A matrix of species abundances (species x size). Defaults to the initial abundances stored in params.

n_pp

A vector of the resource abundance by size. Defaults to the initial resource abundance stored in params.

n_other

A named list of the abundances of other dynamical components. Defaults to the initial values stored in params.

w_R

An average size (in grams) of primary producers in the resource spectrum, used to set the size-dependent resource trophic level. Defaults to 1e-10.

beta_R

An average predator/prey mass ratio for the resource spectrum, used to set the size-dependent resource trophic level. Must be greater than 1. Defaults to 1000.

...

Unused

Value

A named vector with the mean trophic level for each species.

See also

getTrophicLevel()

Other summary functions: getBiomass(), getDiet(), getGrowthCurves(), getN(), getSSB(), getTrophicLevel(), getYield(), getYieldGear()

Examples

getTrophicLevelBySpecies(NS_params)
#>    Sprat  Sandeel   N.pout  Herring      Dab  Whiting     Sole  Gurnard 
#> 3.845388 3.702670 4.723848 3.596897 4.760884 4.958668 4.751892 4.302460 
#>   Plaice  Haddock      Cod   Saithe 
#> 4.417412 4.481840 5.241173 5.200990