The European trade ban on wild birds reduced invasion risks

Laura Cardador,Martina Carrete,Pedro Abellán,José L Tella,José D Anadón

doi:10.1111/conl.12631

Abstract

AbstractInternational wildlife trade is a major source of current biological invasions. However, the power of trade regulations to reduce invasion risks at large, continental scales has not been empirically assessed. The European wild bird trade ban was implemented in 2005 to counter the spread of the avian flu. We tested whether the ban reduced invasion risk in two European countries, where 398 nonnative bird species were introduced into the wild from 1912 to 2015. The number of newly introduced species per year increased exponentially until 2005 (in parallel with the volume of wild bird importations), and then sharply decreased in subsequent years. Interestingly, a rapid trade shift from wild‐caught birds to captive‐bred birds, which have lower invasive potential than wild‐caught birds, allowed the maintenance of bird availability in markets. Our results demonstrate the effectiveness of a trade ban for preventing biological invasions without impacting the ability to meet societal demands.

Highlights

Biological invasions are a significant component of global change through their effects on biodiversity, ecosystems, and human societies (Millennium Ecosystem Assessment 2005; Vilà et al, 2010)
While studies directly assessing the effects of trade restrictions on invasion risks are absent, the declines in nonnative plants established in New Zealand in the 1990s, coinciding with the application of stringent biosecurity policies (Biosecurity Act adopted in 1993), seems to support this idea (Seebens et al, 2017)
Temporal changes in the number of new nonnative species introduced paralleled the annual numbers of wild individuals and species imported in the previous year (67.3% of the variability in introductions explained by these variables, Figure 1 and Supporting Information Table S1)

Summary

Introduction

Biological invasions are a significant component of global change through their effects on biodiversity, ecosystems, and human societies (Millennium Ecosystem Assessment 2005; Vilà et al, 2010). Propagule pressure and colonization pressure (Lockwood, Cassey, & Blackburn, 2009) are known to be major predictors of invasion success and alien species richness (Blackburn, Lockwood, & Cassey, 2015; Lockwood, Cassey, & Blackburn, 2005, 2009). For these reasons, it has been assumed that both the number of introduction events and, in general, invasion risks should decrease after trade restrictions (Simberloff et al, 2013). The responsibility for protection against invasive species lies mostly with national governments

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Conclusion