Polar Bear Maternal Den Habitat in the Arctic National Wildlife Refuge, Alaska

Durner, George M.; Amstrup, Steven C.; Ambrosius, Ken

doi:10.14430/arctic361

Cited by 10 publications

(20 citation statements)

References 20 publications

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“…We calculated that 20 dens could be present in the 1002 Area during any given winter (Appendix A). We allowed simulated dens to occur only on suitable den habitat identified by Durner et al (2006). For each iteration of the model, we randomly distributed the dens across the 1002 Area areas along features identified as denning habitat (Durner et al 2006), with the probability of a den occurring at a given location being proportional to the density of dens predicted by the kernel density map.…”

Section: Den Simulationmentioning

confidence: 99%

“…Forwardlooking infrared imagery is a tool that is commonly used to accomplish this task (Amstrup et al 2004). To obtain FLIR imagery, aerial surveys are conducted in December and January with FLIR sensors mounted to either helicopters or airplanes along polar bear denning habitat (Durner et al 2006) in a region of interest. Imagery is monitored real-time and through post hoc review for hotspots that have characteristics consistent with a polar bear den (Amstrup et al 2004).…”

Section: Den Detectionmentioning

confidence: 99%

“…Amstrup (1993) reported that 34% of land-based dens in the range of the SBS population occurred inside the 1002 Area, even though it represents only 10% of the mainland coastline where bears can den. The area contains 3,163 km of potential denning habitat (based on terrain capable of capturing snow suitable for denning), with 38% more present in the 1002 Area than areas to the west (Durner et al 2006. Because of the relatively high proportion of polar bear maternal dens and denning habitat compared to elsewhere in northern Alaska, 77% of the 1002 Area has been designated as critical denning habitat (U.S.…”

mentioning

confidence: 99%

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Seismic Survey Design and Effects on Maternal Polar Bear Dens

Wilson

Durner

2019

J Wildl Manag

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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.

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Section: Den Simulationmentioning

confidence: 99%

Section: Den Detectionmentioning

confidence: 99%

mentioning

confidence: 99%

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Seismic Survey Design and Effects on Maternal Polar Bear Dens

Wilson

Durner

2019

J Wildl Manag

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“…To ensure that wintertime oil and gas exploration and development activities do not disrupt denning and threaten survival of cubs, managers require knowledge of the distribution of the landscape features that are capable of accumulating snow deep enough for pregnant polar bears to dig maternal dens. Photogrammatic techniques have been used to map polar bear denning habitat in the eastern and central portions of the ACP (Durner et al, 2001(Durner et al, , 2006, but the necessary photography has not been available for the western ACP. Here, we present a new method-the automated interpretation of fine-grain digital elevation data-for mapping potential polar bear maternal denning habitat in the coastal regions of the National Petroleum Reserve -Alaska (NPR-A) in the northwest ACP.…”

Section: Introductionmentioning

confidence: 99%

“…Denning habitats include coastal banks, riverbanks, lakeshores, and even some human-made features (Durner et al, 2001(Durner et al, , 2003. On the coastal plain of northern Alaska east of the Colville River, suitable denning habitat comprises less than 1% of the total area (Durner et al, 2001(Durner et al, , 2006), yet approximately 63% of pregnant polar bears in the SB subpopulation rely on terrestrial habitat for maternal denning each winter, and the proportion of on-land denning is increasing (Amstrup and Gardner, 1994;Fischbach et al, 2007). Though most terrestrial denning has occurred within 2 km of the coast (Durner et al, 2003), some polar bear dens have been observed 61 km inland of the Beaufort Sea coast ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Mapping Polar Bear Maternal Denning Habitat in the National Petroleum Reserve–Alaska with an IfSAR Digital Terrain Model

Durner¹,

Simac²,

Amstrup³

2013

ARCTIC

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The National Petroleum Reserve-Alaska (NPR-A) in northeastern Alaska provides winter maternal denning habitat for polar bears (Ursus maritimus) and also has high potential for recoverable hydrocarbons. Denning polar bears exposed to human activities may abandon their dens before their young are able to survive the severity of Arctic winter weather. To ensure that wintertime petroleum activities do not threaten polar bears, managers need to know the distribution of landscape features in which maternal dens are likely to occur. Here, we present a map of potential denning habitat within the NPR-A. We used a fine-grain digital elevation model derived from Interferometric Synthetic Aperture Radar (IfSAR) to generate a map of putative denning habitat. We then tested the map's ability to identify polar bear denning habitat on the landscape. Our final map correctly identified 82% of denning habitat estimated to be within the NPR-A. Mapped denning habitat comprised 19.7 km 2 (0.1% of the study area) and was widely dispersed. Though mapping denning habitat with IfSAR data was as effective as mapping with the photogrammetric methods used for other regions of the Alaskan Arctic coastal plain, the use of GIS to analyze IfSAR data allowed greater objectivity and flexibility with less manual labor. Analytical advantages and performance equivalent to that of manual cartographic methods suggest that the use of IfSAR data to identify polar bear maternal denning habitat is a better management tool in the NPR-A and wherever such data may be available.

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Landscape impacts of 3D‐seismic surveys in the Arctic National Wildlife Refuge, Alaska

Raynolds

Jorgenson

Jorgenson³

et al. 2020

Ecological Applications

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Although three-dimensional (3D) seismic surveys have improved the success rate of exploratory drilling for oil and gas, the impacts have received little scientific scrutiny, despite affecting more area than any other oil and gas activity. To aid policy-makers and scientists, we reviewed studies of the landscape impacts of 3D-seismic surveys in the Arctic. We analyzed a proposed 3D-seismic program in northeast Alaska, in the northern Arctic National Wildlife Refuge, which includes a grid 63,000 km of seismic trails and additional camp-move trails. Current regulations are not adequate to eliminate impacts from these activities. We address issues related to the high-density of 3D trails compared to 2D methods, with larger crews, more camps, and more vehicles. We focus on consequences to the hilly landscapes, including microtopography, snow, vegetation, hydrology, active layers, and permafrost. Based on studies of 2D-seismic trails created in 1984-1985 in the same area by similar types of vehicles, under similar regulations, approximately 122 km 2 would likely sustain direct medium-to high-level disturbance from the proposed exploration, with possibly expanded impacts through permafrost degradation and hydrological connectivity. Strong winds are common, and snow cover necessary to minimize impacts from vehicles is windblown and inadequate to protect much of the area. Studies of 2D-seismic impacts have shown that moist vegetation types, which dominate the area, sustain longer-lasting damage than wet or dry types, and that the heavy vehicles used for mobile camps caused the most damage. The permafrost is ice rich, which combined with the hilly topography, makes it especially susceptible to thermokarst and erosion triggered by winter vehicle traffic. The effects of climate warming will exacerbate the impacts of winter travel due to warmer permafrost and a shift of precipitation from snow to rain. The cumulative impacts of 3D-seismic traffic in tundra areas need to be better assessed, together with the effects of climate change and the industrial development that would likely follow. Current data needs include studies of the impacts of 3D-seismic exploration, better climate records for the Arctic National Wildlife Refuge, especially for wind and snow; and high-resolution maps of topography, ground ice, hydrology, and vegetation.

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Polar Bear Maternal Den Habitat in the Arctic National Wildlife Refuge, Alaska

Cited by 10 publications

References 20 publications

Seismic Survey Design and Effects on Maternal Polar Bear Dens

Seismic Survey Design and Effects on Maternal Polar Bear Dens

Mapping Polar Bear Maternal Denning Habitat in the National Petroleum Reserve–Alaska with an IfSAR Digital Terrain Model

Landscape impacts of 3D‐seismic surveys in the Arctic National Wildlife Refuge, Alaska

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