Index‐based approach for estimating vulnerability of Arctic biota to oil spills

Abstract

Citation: Nevalainen, M., J. Vanhatalo, and I. Helle. 2019. Index-based approach for estimating vulnerability of Arctic biota to oil spills. Ecosphere 10(6):Abstract. Risk of an Arctic oil spill has become a global matter of concern. Climate change induced opening of shipping routes increases the Arctic maritime traffic which exposes the area to negative impacts of potential maritime accidents. Still, quantitative analyses of the likely environmental impacts of such accidents are scarce, and our understanding of the uncertainties related to both accidents and their consequences is poor. There is an obvious need for analysis tools that allow us to systematically analyze the impacts of oil spills on Arctic species, so the risks can be taken into account when new sea routes or previously unexploited oil reserves are utilized. In this paper, an index-based approach is developed to study exposure potential (described via probability of becoming exposed to spilled oil) and sensitivity (described via oil-induced mortality and recovery) of Arctic biota in the face of an oil spill. First, a conceptual model presenting the relevant variables that contribute to exposure potential and sensitivity of key Arctic marine functional groups was built. Second, based on an extensive literature review, a probabilistic estimate was assigned for each variable, and the variables were combined to an index representing the overall vulnerability of Arctic biota. The resulting index can be used to compare the relative risk between functional groups and accident scenarios. Results indicate that birds have the highest vulnerability to spilled oil, and seals and whales the lowest. Polar bears' vulnerability varies greatly between seasons, while ice seals' vulnerability remains the same in every accident scenario. Exposure potential of most groups depends strongly on type of oil, whereas their sensitivity contains less variation.

Seabird vulnerability to oil: Exposure potential, sensitivity, and uncertainty in the northern Gulf of Mexico

“…We developed the VSOI by adapting recently described frameworks and index-based approaches that assessed the potential impacts of offshore energy development on marine fauna and then tailored it to the current state of knowledge of seabirds in the nGoM. Our approach was informed by similar efforts (e.g., Kelsey et al, 2018) and proposed frameworks (Polidoro et al, 2021) and the terms used in our approach are most closely related to those described in Nevalainen et al (2019). The framework applied by Nevalainen et al (2019) best reflects the current state of knowledge for seabirds in the nGoM.…”

“…Assessing the risk that oiling poses to seabirds requires estimating exposure, sensitivity, and vulnerability. Herein, we define these terms similar to Nevalainen et al (2019). Exposure relates to a species' potential co-occurrence with oil, and sensitivity relates to the probability of mortality due to contact with oil and, subsequently, the relative impact on the population.…”

“…Some exclusively assess spatial or temporal overlap (e.g., exposure to shipping, recreational boating, or O&G platforms; Humphries and Huettmann, 2014;Lieske et al, 2014;Renner and Kuletz, 2015;Fox et al, 2016). Others consider behavioral and life-history characteristics (e.g., sensitivity; Romero et al, 2018), and some have assessed a combination of life history and habitat overlap (Nevalainen et al, 2019). Some have also proposed (e.g., Polidoro et al, 2021; applied to marine fishes only in Woodyard et al, 2022), and others have applied (e.g., Nevalainen et al, 2019) indices across taxa.…”

“…Others consider behavioral and life-history characteristics (e.g., sensitivity; Romero et al, 2018), and some have assessed a combination of life history and habitat overlap (Nevalainen et al, 2019). Some have also proposed (e.g., Polidoro et al, 2021; applied to marine fishes only in Woodyard et al, 2022), and others have applied (e.g., Nevalainen et al, 2019) indices across taxa. All of the indices above that have been applied to seabirds occur in polar to temperate environments.…”

“…Some studies have intentionally presented indices at a relatively coarse spatial resolution to prevent over-interpretation (Fox et al, 2016). Other indices have characterized uncertainty through quantitative scoring of qualitative uncertainty ranks (Kelsey et al, 2018) or probability distributions (Nevalainen et al, 2019). Relative to other O&G extraction regions in the United States, few studies on the distribution and demographics of seabirds in the nGoM have been undertaken, making it challenging to apply detailed indices (e.g., Polidoro et al, 2021) without very high levels of uncertainty.…”