Seismic Survey Design and Effects on Maternal Polar Bear Dens

Abstract

Large‐scale industrial activities can have negative effects on wildlife populations. Some of these effects, however, could be reduced with effective planning prior to development. The Coastal Plain of the Arctic National Wildlife Refuge, in northeastern Alaska, USA, is an important maternal denning area for polar bears (Ursus maritimus). Recent legislation has opened the area for potential oil and gas development. As a result, there is interest in conducting winter seismic surveys across the area that could disturb denning female polar bears and lead to decreased cub survival. We sought to demonstrate how different seismic survey designs, with and without aerial den detection surveys, could affect the level of potential effect on denning polar bears during spring (Feb–Apr). We developed 5 hypothetical seismic survey designs for a portion of the Coastal Plain ranging from no spatial or temporal restrictions on activities to explicit consideration of when and where operations can occur. We evaluated how many dens might be disturbed by seismic surveys and the average distance activity came within simulated polar bear dens. Survey design had a large effect on the estimated number of dens that could be disturbed; the scenario with the highest spatial and temporal specificity reduced the number of dens disturbed by >90% compared to the scenario with no restrictions on when and where activity could occur. The use of an aerial den detection survey prior to seismic activity further reduced the number of dens disturbed by 68% across all scenarios. The scenario with the highest spatial and temporal specificity always had the lowest level of disturbance for all scenarios with and without the aerial survey included. Our study suggests that large reductions in the probability of disturbance can occur through careful planning on the timing and distribution of proposed activities even when surveys are planned in areas with a high density of polar bear dens. Published 2019. This article is a U.S. Government work and is in the public domain in the USA. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

Estimating the Audibility of Industrial Noise to Denning Polar Bears

“…Industrial activity is expected to increase with further declines in Arctic sea ice (Van Hemert et al 2015, Nevalainen et al 2017). In Alaska, there has been renewed interest in oil and gas exploration across the Arctic Coastal Plain (Pearce et al 2018, Wilson and Durner 2020). Substantial noise is associated with some industrial activities (Geraci and Aubin 1980) and management concerns exist regarding its effect on parturient females in snow dens (Perham 2005, Wilson and Durner 2020).…”

“…In Alaska, there has been renewed interest in oil and gas exploration across the Arctic Coastal Plain (Pearce et al 2018, Wilson and Durner 2020). Substantial noise is associated with some industrial activities (Geraci and Aubin 1980) and management concerns exist regarding its effect on parturient females in snow dens (Perham 2005, Wilson and Durner 2020). Although reports are rare, polar bears have exhibited den abandonment due to noise disturbance from human activity (Belikov 1976, Lentfer and Hensel 1980, Amstrup 1993, Larson et al 2020).…”

“…A den simulation used this buffer to assess the potential for polar bear den disturbance based on 5 different seismic survey designs (Wilson and Durner 2020). This study reported den disturbance could be best reduced by timing seismic surveys to be later in the winter potentially after bears have emerged from dens and by using forward‐looking infrared surveys (FLIR) to detect dens prior to seismic activities (Wilson and Durner 2020). But other researchers have reported FLIR surveys to be less effective in identifying polar bear maternal dens than previously documented (Smith et al 2020).…”

“…But other researchers have reported FLIR surveys to be less effective in identifying polar bear maternal dens than previously documented (Smith et al 2020). Additionally, Wilson and Durner's (2020) simulation was reliant on the assumption that polar bears in maternal dens will only be disturbed by seismic activities occurring within 1.6 km. The potential for industrial activity to affect maternal denning, coupled with the ethical and regulatory restrictions that preclude the implementation of disturbance experiments on polar bears, prompt the need to gather fundamental data on their acoustic ecology, including a detailed description of industrial noise propagation into maternal dens at different snow depths.…”

“…Currently, United States federal regulations require a 1.6-km buffer zone around active polar bear dens (U.S. Fish and Wildlife Service 2016). A den simulation used this buffer to assess the potential for polar bear den disturbance based on 5 different seismic survey designs (Wilson and Durner 2020). This study reported den disturbance could be best reduced by timing seismic surveys to be later in the winter potentially after bears have emerged from dens and by using forwardlooking infrared surveys (FLIR) to detect dens prior to seismic activities (Wilson and Durner 2020).…”