getDiet {mizer}

Get diet of predator at size, resolved by prey species

Description

Calculates the rate at which a predator of a particular species and size consumes biomass of each prey species and resource. The diet has units of grams/year.

Usage

getDiet(
  params,
  n = initialN(params),
  n_pp = initialNResource(params),
  n_other = initialNOther(params),
  proportion = TRUE
)

Arguments

params

A MizerParams object

n

A matrix of species abundances (species x size).

n_pp

A vector of the resource abundance by size

n_other

A list of abundances for other dynamical components of the ecosystem

proportion

If TRUE (default) the function returns the diet as a proportion of the total consumption rate. If FALSE it returns the consumption rate in grams per year.

Details

Returns the rates D_{ij}(w) at which a predator of species i and size w consumes biomass from prey species j. This is calculated from the predation kernel \phi_i(w, w_p), the search volume \gamma_i(w), the feeding level f_i(w), the species interaction matrix \theta_{ij} and the prey abundance density N_j(w_p):

D_{ij}(w, w_p) = (1-f_i(w)) \gamma_i(w) \theta_{ij} \int N_j(w_p) \phi_i(w, w_p) w_p dw_p.

The prey index j runs over all species and the resource. It also runs over any extra ecosystem components in your model for which you have defined an encounter rate function. This encounter rate is multiplied by 1-f_i(w) to give the rate of consumption of biomass from these extra components.

This function performs the same integration as getEncounter() but does not aggregate over prey species, and multiplies by 1-f_i(w) to get the consumed biomass rather than the available biomass. Outside the range of sizes for a predator species the returned rate is zero.

Value

An array (predator species x predator size x (prey species + resource + other components) )

See Also

plotDiet()

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

Examples

diet <- getDiet(NS_params)
str(diet)