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From left to right: forward‐looking infrared image of an artificial polar bear den at a distance of 50 m vertical above the den, post‐processed using a “segment” feature to eliminate colder pixels from image (a), to partially segmented image (b), and leave only the warmer pixels associated with the den “hot spot” in image (c) to be counted using a “region of interest” (circle) as a means to evaluate the quality of the detection in comparison to other detections at this distance
Source publication
Abstract Industrial off‐road activity in winter overlaps denning habitat of polar bear (Ursus maritimus) and grizzly bear (Ursus arctos) in the North Slope oilfields of Alaska (United States). To prevent disturbance of dens, managers have used forward‐looking infrared (FLIR) cameras to detect dens, but the effectiveness of FLIR under different envi...
Citations
... Ground-based and aerial-based surveys for dens have been used to monitor populations of kit foxes in desert environments (O'Farrell 1987) and red foxes in prairie ecosystems (Trautman et al. 1974). In the Arctic, dens of polar bears (Ursus maritimus) have been located with forward-looking infrared (FLIR) cameras, but with mixed results depending on detection platform (helicopter, airplane, or ground-based), environmental conditions (e.g., ambient temperature, wind speed, precipitation, amount of sunlight) and thickness of den ceiling (Amstrup et al. 2004, Pedersen et al. 2020, Woodruff et al. 2022. ...
... Habitat study Ursus maritimus [130] Octocopter rotarywing ...
... Indirect applications such as habitat studies can make use of UAVs. For example, IRT imagery has been applied to identify occupied polar bear dens by detecting differences in snow surface temperature [130], and photogrammetric methods applied to aerial imagery have been used to calculate the height of icebergs and estimate their accessibility as haul-out sites for harbour seals [53]. Also, Yamato et al. [70] used UAV-based photogrammetry methods to detect dugong feeding traits in intertidal seagrass beds. ...
Research on the ecology and biology of marine mammal populations is necessary to understand ecosystem dynamics and to support conservation management. Emerging monitoring tools and instruments offer the opportunity to obtain such information in an affordable and effective way. In recent years, unmanned aerial vehicles (UAVs) have become an important tool in the study of marine mammals. Here, we reviewed 169 research articles using UAVs to study marine mammals, published up until December 2022. The goals of these studies included estimating the number of individuals in populations and groups via photo-identification, determining biometrics and body condition through photogrammetry, collecting blow samples, and studying behavioural patterns. UAVs can be a valuable, non-invasive, and useful tool for a wide range of applications in marine mammal research. However, it is important to consider some limitations of this technology, mainly associated with autonomy, resistance to the marine environment, and data processing time, which could probably be overcome in the near future.
... Aerial infrared (AIR) sensors have wide use in commerce, law enforcement, industry, and wildlife management (https://www.flir.com/; Accessed 7 Dec 2020), and the technology has potential value in polar bear conservation , Pedersen et al. 2020. The physical properties of a substrate (e.g., snow or soil) and exposure to environmental conditions can cause surfaces or objects to present temperatures expressed in different infrared (IR) wavelengths. ...
... The estimate from Amstrup et al. (2004), on the other hand, was derived from 67 helicopter flights over 23 dens whose general locations were known to flight crews. Despite differences in methodology, all studies showed den detection decreased with increasing air temperature, higher wind speed, and solar radiation, and when precipitation or fog was present , Robinson et al. 2014, Pedersen et al. 2020). In ground-based studies using handheld IR cameras, detection of artificial polar bear dens was inversely related to snow thickness over the den (Robinson et al. 2014). ...
... Similar to other artificial polar bear den studies (Robinson et al. 2014, Pedersen et al. 2020, each den included 2, 100-watt silicone oil pan heaters (Model 24100; Kat's Heaters, Springfield, TN, USA) to simulate the heat generated by a denning polar bear (Watts 1983). Heaters were expected to stabilize at an internal temperature of 0°C after the den was sealed. ...
The need to balance economic development with impacts to Arctic wildlife has been a prominent subject since petroleum exploration began on the North Slope of Alaska, USA, in the late 1950s. The North Slope region includes polar bears (Ursus maritimus) of the southern Beaufort Sea subpopulation, which has experienced a long‐term decline in abundance. Pregnant polar bears dig dens in snow drifts during winter and are vulnerable to disturbance, as den abandonment and mortality of neonates may result. Maternal denning coincides with the peak season of petroleum exploration and construction, raising concerns that human activities may disrupt denning. To minimize disturbance of denning polar bears, aerial infrared (AIR) surveys are routinely used to search for dens within planned industry activity areas and that information is used to implement mitigation. Aerial infrared surveys target the heat signature emanating from dens. Despite use by industry for >15 years, the efficacy of AIR and the factors that impact its ability to detect dens remains uncertain. Here, we evaluate AIR using artificial dens and observers naïve to locations to estimate detection probability and its relationship with covariates including weather variables, den characteristics, infrared sensor and altitude, and survey order to identify potential evidence of in‐flight observer learning occurring between surveys. In December 2019 we constructed 14 dens (each with an artificial heat source), and 11 control sites (disturbed sites without dens). Between December 2019 and January 2020, 3 survey crews flew 6 independent AIR surveys within the vicinity of dens and control sites and video‐recorded AIR imagery. Observers identified putative dens either in flight or during post‐flight review of recordings. We assessed detection probability with a simple Bayesian model using 3 subsets of data: 1) all detection/non‐detection data; 2) detection/non‐detection data restricted to instances where sample sites were confirmed to have been properly scanned by AIR during post‐study verification (i.e., when den locations were known); and 3) all dens visible on the recorded imagery during post‐study verification, even if they were not seen during the survey or during post‐flight review. Subsets 1 and 2 most closely resembled den surveys flown for oil and gas industry and had detection probabilities of 0.15 (95% CI = 0.08–0.23) and 0.24 (95% CI = 0.13–0.37), respectively. Detection probability was 0.41 (95% CI = 0.25–0.58) for subset 3. Higher wind speeds and larger den volume negatively influenced detection probability. Our low detection rate compared to previous studies could partially be the result of differences in study design, such as survey flight patterns. Our results suggest that AIR, as it is currently used, is unlikely to detect most polar bear dens in surveyed areas. Resource managers who use AIR should consider a suite of additional methods (e.g., habitat mapping, probabilistic den distribution, AIR methodology improvements) for minimizing impacts of industry on denning polar bears. We evaluated the efficacy of aerial infrared surveys using artificial dens and observers naïve to den locations to estimate den detection probability. Our results suggest that aerial infrared surveys are unlikely to detect most polar bear dens in surveyed areas. Resource managers who use AIR should consider additional methods for minimizing impacts of industry on denning polar bears.
Climate-induced sea-ice loss represents the greatest threat to polar bears (Ursus maritimus Phipps, 1774), and utilizing drones to characterize behavioural responses to sea-ice loss is valuable for forecasting polar bear persistence. In this manuscript, we review previously published literature and draw on our own experience of using multirotor aerial drones to study polar bear behaviour in the Canadian Arctic. Specifically, we suggest that drones can minimize human–bear conflicts by allowing users to observe bears from a safe vantage point; produce high-quality behavioural data that can be reviewed as many times as needed and shared with multiple stakeholders; and foster knowledge generation through co-production with northern communities. We posit that in some instances drones may be considered as an alternative tool for studying polar bear foraging behaviour, interspecific interactions, human–bear interactions, human safety and conflict mitigation, and den-site location at individual-level small spatial scales. Finally, we discuss flying techniques to ensure ethical operation around polar bears, regulatory requirements to consider, and recommend that future research focus on understanding polar bears’ behavioural and physiological responses to drones and the efficacy of drones as a deterrent tool for safety purposes.
