Stapleton Seth, LaRue Michelle, Lecomte Nicolas, Atkinson Stephen, Garshelis David, Porter Claire, Atwood Todd
United States Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America.
Department of Earth Sciences, University of Minnesota, Minneapolis, Minnesota, United States of America.
PLoS One. 2014 Jul 9;9(7):e101513. doi: 10.1371/journal.pone.0101513. eCollection 2014.
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.
开发高效的野生动物监测技术是北极地区的一项优先任务，在北极，气候变化的影响十分严重，偏远地区以及后勤方面的限制阻碍了人们进入该地区。我们评估了高分辨率卫星图像作为追踪北极熊分布和数量的工具。我们研究了加拿大福克斯湾一个小岛的卫星图像，在夏季无冰季节，该岛上北极熊密度很高。通过比较不同日期收集的图像，将北极熊与其他浅色斑点区分开来。一组经过实地验证的点样本表明我们对北极熊的分类是准确的。独立观察员审查了图像，并使用标记重捕模型获得了种群估计数。这个估计数（N：94；95%置信区间：92 - 105）与几天前通过线 transect 航空调查得出的数量估计数（N：102；95%置信区间：69 - 152）非常相似。我们的研究结果表明，卫星图像是监测陆地上北极熊的一种很有前景的工具，对用于其他北极野生动物也有启示意义。大规模应用可能需要开发自动检测程序以加快审查和分析。未来的研究应该评估多光谱图像的效用，并研究具有不同环境特征的地点。
