Effects of dispersal on local population increase

Research on the spread of invading organisms or biological control agents has focused on rates of spread rather than on the influence of dispersal on rates of local population increase. Based on a simple general model for logistic local growth and one-dimensional diffusive dispersal, the authors showed that dispersal can be a substantial drain on populations. At release sites, population increase was always slower than would be expected without dispersal, while at distant invaded sites, dispersal initially enhanced but later reduced the rate of population increase. The findings have important implications for population parameter estimates of invading organisms or biological control agents and help explain why biological invasions often involve a characteristic .