Polar Bears from Space: Assessing Satellite Imagery as a Tool to Track Arctic Wildlife

Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small island in Foxe Basin, Canada, occupied by a high density of bears during the summer ice-free season. Bears were distinguished from other light-colored spots by comparing images collected on different dates. A sample of ground-truthed points demonstrated that we accurately classified bears. Independent observers reviewed images and a population estimate was obtained using mark–recapture models. This estimate (: 94; 95% Confidence Interval: 92–105) was remarkably similar to an abundance estimate derived from a line transect aerial survey conducted a few days earlier (: 102; 95% CI: 69–152). Our findings suggest that satellite imagery is a promising tool for monitoring polar bears on land, with implications for use with other Arctic wildlife. Large scale applications may require development of automated detection processes to expedite review and analysis. Future research should assess the utility of multi-spectral imagery and examine sites with different environmental characteristics.

[1]  David R. Anderson,et al.  Model selection and multimodel inference : a practical information-theoretic approach , 2003 .

[2]  R. Huggins.  On the statistical analysis of capture experiments , 1989 .

[3]  Wieslaw Maslowski,et al.  The Future of Arctic Sea Ice , 2012 .

[4]  R. Huggins.  Some practical aspects of a conditional likelihood approach to capture experiments , 1991 .

[5]  J. Ragle,et al.  IUCN Red List of Threatened Species , 2010 .

[6]  Josefino C. Comiso,et al.  Accelerated decline in the Arctic sea ice cover , 2008 .

[7]  Len Thomas,et al.  Distance software: design and analysis of distance sampling surveys for estimating population size , 2009, The Journal of applied ecology.

[8]  M. Holland,et al.  Arctic sea ice decline: Faster than forecast , 2007 .

[9]  S. Amstrup,et al.  A circumpolar monitoring framework for polar bears , 2012 .

[10]  S. Amstrup,et al.  Effects of Earlier Sea Ice Breakup on Survival and Population Size of Polar Bears in Western Hudson Bay , 2007 .

[11]  J. Huba,et al.  Simulation of the seeding of equatorial spread F by circular gravity waves , 2013 .

[12]  K. Burnham,et al.  Program MARK: survival estimation from populations of marked animals , 1999 .

[13]  S. T. Buckland,et al.  Marine Mammal Survey and Assessment Methods , 1999 .

[14]  Gerald L. Kooyman,et al.  An Emperor Penguin Population Estimate: The First Global, Synoptic Survey of a Species from Space , 2012, PloS one.

[15]  David R. Anderson,et al.  Null Hypothesis Testing: Problems, Prevalence, and an Alternative , 2000 .

[16]  Ø. Wiig,et al.  Polar bears : proceedings of the working meeting of the IUCN/SSC Polar Bear Specialist Group , 1995 .

[17]  Jay Barlow,et al.  LESSONS FROM MONITORING TRENDS IN ABUNDANCE OF MARINE MAMMALS , 2007 .

[18]  Muyin Wang,et al.  When will the summer Arctic be nearly sea ice free? , 2013 .

[19]  David R. Anderson,et al.  Advanced distance sampling , 2004 .

[20]  J. Rotella,et al.  Satellite imagery can be used to detect variation in abundance of Weddell seals (Leptonychotes weddellii) in Erebus Bay, Antarctica , 2011, Polar Biology.

[21]  M. Obbard,et al.  Polar bears: proceedings of the 15th Working Meeting of the IUCN/SSC Polar Bear Specialist Group, Copenhagen, Denmark, 29 June3 July 2009 , 2010 .

[22]  J. Kay,et al.  The Arctic’s rapidly shrinking sea ice cover: a research synthesis , 2012, Climatic Change.

[23]  K. Rode,et al.  Effects of sea ice extent and food availability on spatial and temporal distribution of polar bears during the fall open-water period in the Southern Beaufort Sea , 2008, Polar Biology.

[24]  David R. Anderson,et al.  Statistical inference from capture data on closed animal populations , 1980 .

[25]  J. Aars,et al.  The Use of Global Positioning Systems to Record Distances in a Helicopter Line-Transect Survey , 2006 .

[26]  N. G. Platonov,et al.  The possibility of using high resolution satellite images for detection of marine mammals , 2013, Biology Bulletin.

[27]  Ian Stirling,et al.  Quantifying the sensitivity of Arctic marine mammals to climate-induced habitat change. , 2008, Ecological applications : a publication of the Ecological Society of America.

[28]  S. Buckland.  Introduction to distance sampling : estimating abundance of biological populations , 2001 .