Large-Scale Impacts of the Deepwater Horizon Oil Spill: Can Local Disturbance Affect Distant Ecosystems through Migratory Shorebirds?

The 2010 Deepwater Horizon oil spill, the largest ever accidental release of oil into marine waters, affected hundreds of miles of US northern Gulf of Mexico coastline that is important habitat for migratory shorebirds. Shorebirds are particularly susceptible to oil contamination because of their subsurface probe-foraging behavior and reliance on intertidal habitat. More than one million migratory shorebirds representing 28 species were potentially exposed to Deepwater Horizon oil during their 2010–2011 nonbreeding season. Although only 8.6% of the shorebirds trapped from fall 2010 to spring 2011 showed visible signs of oiling, nonlethal effects and degradation of habitat can affect populations in ways that carry over into subsequent seasons. Here, we discuss how the spill could affect populations of migratory shorebirds through acute mortality, as well as through long-term and indirect pathways. We also discuss the potential impacts on ecosystems far from the spill, including prairie grasslands and the Arctic, where migratory shorebirds breed.