predprey: Predator-prey model
In caspr: Cellular Automata for Spatial Pressure in R

Description Usage Arguments Format Details Author(s) References See Also

A spatially-explicit predator prey model.

1	ca(l, predprey, parms = p)

`betaf`	A numerical value. The reproduction rate of prey.
`betas`	A numerical value. reproduction rate of predators.
`delta`	A numerical value. Probability of starvation for predators that do not find prey.

List of 6
 $ name  : chr "Predator-prey Gap Model"
 $ ref   : chr "Pascual, M., Roy, M., Guichard, F., & Flierl, G. (2002). Cluster size distributions: signatures of self-organization in spatial"| __truncated__
 $ states: chr [1:3] "f" "s" "0"
 $ cols  : chr [1:3] "gray50" "black" "white"
 $ parms :List of 3
  ..$ betaf: num 0.01
  ..$ betas: num 0.1
  ..$ delta: num 0.2
 $ update:function (x, parms, subs = prod(x$dim))  
  ..- attr(*, "srcref")=Class 'srcref'  atomic [1:8] 61 20 80 1 20 1 61 80
  .. .. ..- attr(*, "srcfile")=Classes 'srcfilecopy', 'srcfile' <environment: 0x43a8ae0> 
 - attr(*, "class")= chr "ca_model"

The particular neighbourhood we consider in the simulations consists of the four nearest sites. Prey growth occurs as a contact process: a prey chooses a neighbouring site at random and gives birth onto it only if this site is empty at rate betas. Predators hunt for prey by inspecting their neighbourhood for the presence of prey at rate 1. If prey are present, the predator selects one at random and eats it, moving to this neighbouring site. Only predators that find a prey can reproduce, and do so with a specified probability, betas. The offspring is placed in the original site of the predator. Predators that do not find prey are susceptible to starvation and die with a probability delta. Random movement occurs through mixing: neighbouring sites exchange state at a constant rate nu.

Mercedes Pascual, M. Roy, F. Guichard & G. Flierl

Pascual, M., Roy, M., Guichard, F., & Flierl, G. (2002). Cluster size distributions: signatures of self-organization in spatial ecologies. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 357(1421), 657<e2><80><93>666. doi: 10.1098/rstb.2001.0983

Other models: forestgap; grazing; life; livestock; musselbed