flex.dispersal: perform species-specific dispersal and fluctuating source...
In coexist: Species coexistence modeling and analysis

Description Usage Arguments Author(s) References See Also Examples

perform species-specific dispersal and fluctuating source analysis, for two or multiple species models, it's an internal function

1	flex.dispersal(spvector, initp,dismat, allee = 1,type = "constant")

`spvector`	species-patch abundance matrix prior to dispersal in this time step
`initp`	initial population size for a species that will be released at the source patch at each time step
`dismat`	a list of dispersal matrix for each of the species. The dispersal matrix for the species indicated its dispersal ability and perference across the patches.
`allee`	allee effect for the species, the minimum viable population in a local patch, default=1, indicating that if the population size in a patch for a species is less than 1, then the species will be removed from that patch
`type`	model configuration for the source supply methods, currently there are three types of source species supplying modes: "constant": constant population size of each species will be released at the source patch for each simulation step "flexible": random population size of each species will be released (all species should typically be assigned different values) based on a normal distribution with mean=initp, Variance=initp/2, at the source patch for each simulation step "cochange": random population size (but all species will be assigned a same value) at the source patch for each simulation step

Youhua Chen <yhchen@zoology.ubc.ca>

Chen YH (2012) coexist: an R package for performing species coexistence modeling and analysis under asymmetric dispersal and fluctuating source-sink dynamics. http://code.google.com/p/coexist.

flex.competition, dispersal

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function (spvector, initp,dismat, allee = 1, type = "constant") 
{
    if (type == "constant") {
        spnum <- length(dismat)
        for (i in 1:spnum) {
            spvector[i, ] <- spvector[i, ] %*% dismat[[i]]
            spvector[i, 1] = initp
        }
    }
    if (type == "flexible") {
        spnum <- length(dismat)
        for (i in 1:spnum) {
            spvector[i, ] <- spvector[i, ] %*% dismat[[i]]
            spvector[i, 1] = rnorm(1, mean = initp, sd = initp/10)
        }
    }
    if (type == "cochange") {
        spnum <- length(dismat)
        newresource <- rnorm(1, mean = initp, sd = initp/10)
        for (i in 1:spnum) {
            spvector[i, ] <- spvector[i, ] %*% dismat[[i]]
            spvector[i, 1] = newresource
        }
    }
    spvector[which(spvector < allee)] = 0
    spvector[which(spvector < 0)] = 0
    return(spvector)
  }