getDiet {mizer} | R Documentation |
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, resource, and other components of the ecosystem. Returns either the rates in grams/year or the proportion of the total consumption rate.
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
The rates D_{ij}(w)
at which a predator of species i
and size w
consumes biomass from prey species j
are
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.
Extra columns are added for the external encounter rate and for any extra
ecosystem components in your model for which you have defined an encounter
rate function. These encounter rates are 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). Dimnames are "prey", "w", and "predator".
See Also
Other summary functions:
getBiomass()
,
getGrowthCurves()
,
getN()
,
getSSB()
,
getYield()
,
getYieldGear()
Examples
diet <- getDiet(NS_params)
str(diet)