Globalization and Invasive Alien Species: Trade, Pests, and Pathogens

The risk posed by an introduced species depends on a number of factors, some of which are within the control of regulatory authorities and some of which are not. It is a product of the probability that imports will introduce new species and the expected damage done by those species. Among the risk factors taken as exogenous by the regulatory authorities are the invasiveness of the species itself (whether it is a generalist or a specialist, its plasticity, and so on), the bioclimatic similarity between the trading partners, the volume and composition of trade, and the vulnerability of the host (economic and ecological) system. The sanitary and phytosanitary (SPS) measures taken by the exporter may or may not be taken as exogenous. These together determine both the likelihood that a unit of trade will introduce species of different types and the expected damage if a particular species (or class of species) is introduced. This chapter focuses on the nature of the SPS response to the invasive species risks of international trade, and the effect this has on the dispersion of species. More particularly, it asks what determines current country-level decisions to mitigate the risks of species introductions or to adapt to the consequences of establishment and spread, and how these are reflected in the dispersion data.