title: Polar bears from space: assessing satellite imagery as a tool to track Arctic wildlife.
abstract: 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 (N: 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 (N: 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.
authors.affiliation: United States Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America.
authors.forename: Seth
authors.initials: S
authors.lastname: Stapleton
authors.affiliation: Department of Earth Sciences, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Michelle
authors.initials: M
authors.lastname: LaRue
authors.affiliation: Department of Environment, Government of Nunavut, Igloolik, Nunavut, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Lecomte
authors.affiliation: Department of Environment, Government of Nunavut, Igloolik, Nunavut, Canada.
authors.forename: Stephen
authors.initials: S
authors.lastname: Atkinson
authors.affiliation: Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, St. Paul, Minnesota, United States of America; Minnesota Department of Natural Resources, Grand Rapids, Minnesota, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Garshelis
authors.affiliation: Department of Earth Sciences, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Claire
authors.initials: C
authors.lastname: Porter
authors.affiliation: United States Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America.
authors.forename: Todd
authors.initials: T
authors.lastname: Atwood
mesh_terms: D063147:Animal Distribution; D000818:Animals; D001110:Arctic Regions; D005260:Female; D062312:Islands; D020957:Nunavut; D063809:Satellite Imagery; D001503:Ursidae / Q000502:physiology*