With the projected increases in shipping activity and hydrocarbon extraction globally, there is an increased risk of negative ecological impacts from oil pollution on the marine environment, including seabirds. Oil Vulnerability Indices (OVIs) are a common approach to assess seabird species vulnerability to oil pollution and to identify where species are most at risk, typically across regional spatial scales and for a relatively limited number of species. This approach generally requires comprehensive data on at-sea distributions and densities; however, for many regions, these data are limited. We present a simplified OVI to assess seabird species vulnerability to oil pollution. To create the spatial component of the OVI, we used a predictive foraging radius approach, using existing colony size and foraging range data, to project at-sea distributions of seabird populations during the breeding season. We demonstrate this approach over a large spatial scale, the eastern North Atlantic, which includes areas where seabird at-sea data are lacking. Our results reveal areas off west Greenland, Iceland, and Norway where seabirds are most vulnerable to oil pollution during the breeding season, largely driven by large colonies of auks (Alcidae). We also identify locations along the coast of mainland Norway, Iceland, and Scotland, where seabirds are particularly at risk to oil pollution associated with major shipping routes. Identifying areas where species are most at risk can help inform where, and which, measures should be put in place to mitigate the impacts of oil pollution, such as protecting and avoiding high risk areas, for example, through adopting dynamic Areas to be Avoided (ATBAs). Our simplified OVI combined with the predictive foraging radius approach can be adapted to other regions globally that lack seabird-at-sea distribution data, to other marine wildlife, and to assess risk from hydrocarbon extraction and other anthropogenic threats, including fishing activities and offshore renewable developments.
How to Cite
O'Hanlon, N. J., A. L. Bond, E. A. Masden, D. Boertmann, T. Bregnballe, J. Danielsen, S. Descamps, A. Petersen, H. Strøm, G. Systad, and N. A. James (2023). Using foraging range and colony size to assess the vulnerability of breeding seabirds to oil across regions lacking at-sea distribution data. Ornithological Applications 125:duad030.
LAY SUMMARY
Identifying where seabirds are most at risk to oil pollution can help us take appropriate measures to protect them, such as avoiding oil extraction and major shipping routes in these areas.
Oil Vulnerability Indices (OVIs) are commonly used to assess seabird vulnerability to oil pollution. However, mapping this vulnerability requires at-sea distribution and density data, which are often lacking.
The predictive foraging radius approach uses colony size and foraging range data to estimate seabird at-sea density distribution data.
We combined this approach with a simplified OVI to map breeding seabird vulnerability to oil pollution across the eastern North Atlantic.
This approach revealed that seabirds were most vulnerable to oil pollution off east Greenland, west Iceland, and Norway, where large auk (Alcidae) colonies are located.
By combining mapped seabird vulnerability to oil with vessel density, we also identified locations off Norway, Iceland and Scotland where seabirds are at particular risk to oil pollution from shipping.
