While discussion of adapting to climate change is finally beginning to take off in the United States, other governments from Bangladesh to the Netherlands have already laid the foundation to develop concrete policies and implement strategies to address the impacts. Last week, a report released by the UK’s Environment Agency specifically identified relocation of coldwater fish as a possible direct response to the effects of climate change. We're going to be hearing a lot more in the coming years about assisted migration like this—the intentional relocation of flora or fauna to a new region as a climate change impacts occur.
As a climate change adaptation strategy, assisted migration engenders significant controversy among scientists and policymakers alike. The clear benefit, and intended purpose, is to prevent the extinction of a species that can no longer survive in a changed climate. However, assisted migration raises serious questions about which species to relocate and to where they should be moved. The relocated species are effectively invasive species, which may introduce new diseases, pests, or other unintended consequences. Along with habitat degradation, invasive species are the biggest threat to biodiversity and endangered species. In addition, relocated species may not survive in isolation, so simply moving one targeted species may not ensure its survival.
In the UK, the Environment Agency is "exploring" moving thousands of vendace and schelly, both freshwater white fish, from the northern Lake District in England to cooler waters in Scotland. While still in the planning stages, this strategy represents a remarkably specific and dramatic response to climate change. As with many countries, climate change in the UK is expected to cause an increase in the average temperature and reduced summer rainfall, which lead to higher water temperatures and reduced river flows. Coldwater and migratory fish are particularly sensitive to these changes because increased temperatures and reduced flow affect the breeding and development of these fish. For example, the Environment Agency has linked the alarming decline of eel populations over the past three decades to climate change and rising water temperatures.
By one study, climate change is predicted to cause the extinction of 15 to 37 percent of species in certain regions. Such dramatic declines may warrant dramatic responses such as assisted migration. CPR Member Scholar Alex Camacho recently wrote about the legal and regulatory barriers to assisted migration in the United States, which are likely reflected across much of the world. A proponent of this strategy, he concludes in part that the “prior account of a pristine and untouched nature may be nearing its end.” Instead of a pessimistic forecast, Camacho asserts that this creates the opportunity to move forward by marrying “humanity’s collective self-interest in resource conservation and duties of stewardship” for dynamic biotic and human communities. As assisted migration projects take place around the world, they will provide valuable lessons for how to conduct responsible and successful relocations in our own backyard.