Demography and Dispersal: Models for Biological Invasions

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

This project will develop and analyze models of biological invasions by constructing a mathematical theory describing how populations respond upon arrival in a new area. That theory will provide measures of population performance that can complement those customarily used to measure population viability (e.g., rates of increase and extinction probabilities). The theory will incorporate both demography (i.e., the rates at which individuals move from one life cycle stage to another) and dispersal (i.e., the propensity to move and the directions and distances moved by individuals at each stage of the life cycle). Invasion is an important problem. First, invasive pest species have enormous environmental and economic impact. The problem is not only agricultural; pressures from invasive species are a major impact on endangered endemic species around the world. Understanding the factors determining the success and speed of invasions can provide important guidance for management tactics. Second, a consequence of habitat alteration or climate change will be the movement of species into areas where they previously could not survive. This is another form of invasion, and understanding the factors controlling it is an important part of understanding the effects of climate change. On a positive note, when conservation efforts are successful, species previously eliminated from an area expand their ranges at speeds governed by the same invasion mechanisms.