Globalization and biodiversity

Globalization is widely understood to mean the closer integration of the world’s economies. But globalization also means the closer integration of the world’s ecosystems, and this has important implications for the world’s biodiversity, and the ecosystem services it supports. Globalization in the economic sense is reflected in the growth of international trade and travel. This has increased the rate at which species have dispersed across the world’s ecosystems, with consequences for their functioning and the supply of ecosystem services. The opening of new markets or trade routes has resulted in the introduction of new species either as the object of trade or as the unintended consequence of trade. The growth in the volume of trade along existing routes has increased the frequency with which new introductions are repeated, and hence the probability that introduced species will establish and spread (Cassey et al. 2004; Semmens et al. 2004). Indeed, the more open economies are, the more likely they are to be both sources and sinks for the dispersal of species (Dalmazzone 2000; Vilà and Pujadas 2001), and the volume and direction of trade turn out to be good empirical predictors of the dispersal of harmful species (Levine et al. 2003; Costello et al. 2007).

The effects of trade-related species dispersal are both positive and negative. Trade in high-yielding crop varieties and the diffusion of biotechnologies, for example, have had strongly positive effects on productivity, output, employment, and health. They have also positively affected our capacity to maintain food supplies over a range of environmental conditions. At the same time, the trade-related dispersal of invasive pests and pathogens has had strongly negative effects on the same things. While particular attention has been paid to the harm done by emergent zoonotic diseases in humans (Hubalek 2003; Jones et al. 2008), these are merely the most publicized examples of a widespread and long-standing process of pest and pathogen redistribution (Williamson 1996, 1999; Daszak, Cunningham and Hyatt 2000; McNeely 2001; Daszak et al. 2007).