In nature many organisms can move or can be transferred over large distances. If spread was continuous, then islands would never be colonized by any species. Discontinuous dispersal may result in establishment of isolated colonies far away from the source population. Passive transportation mechanisms are most important for discontinuous dispersal. Distribution of gypsy moth counts in pheromone traps in the Appalachian Mts.
Isolated populations are clearly visible.
The rate of spread, v , can be determined using the traveling wave equation. We assume that the velocity of population spread, v , is stationary. Thus, the traveling wave equation is This equation can be used for estimating the rate of population spread. V x max . We will assume that the barrier zone is placed in the transition zone at some particular distance from the population front.