Up close and grizzly: GPS/camera collar captures bear doings

GPS World, Feb, 2005 by Andrew Hunter, Naser El-Sheimy, Gordon Stenhouse

Integrating a GPS receiver with image processing and geographic information systems (GIS) helps researchers see "the other side of the mountain"--wherever a wild animal goes, and whatever it looks at. This can aid in understanding behavior, improve wildlife management models, and provide accurate reference data for remote sensing applications used to produce habitat maps.

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Understanding biodiversity and its effect on the distribution and movement of animals through the landscape is a major objective of scientists, conservationists, and natural resource managers alike. Only through development of this knowledge can animal populations be managed to meet conservation, sporting, or natural heritage objectives.

According to a 2003 Alberta Sustainable Resource Development report by Gordon Stenhouse (co-author of this article) and colleagues, the population model used to manage grizzly bear numbers in Alberta is incomplete and will continue to predict exponential growth rates when this is not biologically possible. The report suggested modifications so that the model would more accurately reflect current conditions, but the revised model indicated that better inventory data is required to improve population estimates. The report further suggested that current prediction models are most sensitive to the quality of base habitat maps and our understanding of habitat carrying capacity for grizzly bears.

Given the state of the grizzly bear population, if Alberta wishes to continue developing economically with minimal negative effects on its environment, a better understanding of grizzly bear forage resources is desirable at different temporal and spatial scales. These patterns can then be analyzed in combination with estimates of the amount and distribution of important habitat attributes.

We set out to obtain a clearer picture of the habitat through which grizzly bears pass; to increase reference data sample sizes; to gain insights into relationships between bears; and to observe the effect of human development on grizzly bear behavior. To understand animals, researchers must see what the animals see; however, the researcher's presence will often disturb animal movement patterns.

In an effort to improve observation of the grizzlies' behavior, a team of Canadian researchers developed a portable camera system that, combined with a GPS receiver mounted on a collar worn by subject animals, provided images of bears'-eye views of their habitat and the locations at which these photos were taken. This article describes the development of that camera system. When integrated with a GPS receiver, the camera system can also assist with reference data collection required for the creation of habitat maps from satellite imagery, while providing data on the animal's movements. To test the validity of these objectives, we deployed two GPS-camera collars on grizzly bears in the Yellowhead ecosystem of west-central Alberta, Canada.

Habitat Analysis & GPS

A standard field method of habitat analysis in wildlife biology is to visit grizzly bear use sites, typically two to three weeks after the bear has left the area. However, this often results in the loss of information because animal remains may no longer be found and/or vegetation conditions may have changed. Secondly, due to logistic considerations, researchers concentrate on the locations that provide easiest access. Finally, it is not possible to understand from the GPS data alone whether a bear has been accompanied by other bears, or is in a location due to association with other bears, or humans, thus affecting the information that can be derived from habitat use data.

Geomatics technologies are ideally suited to address the limitations of these field techniques. Integration of a GPS receiver with image processing and geographic information systems (GIS) can provide accurate and timely reference data for remote sensing applications that are typically employed in the production of habitat maps.

Hardware Development. Over the winter of 2002/2003, we investigated the hardware necessary for such an application and developed a grizzly bear GPS collar with imaging capabilities. Our team deployed two cameras in the Rocky Mountain foothills for field trials over the summer of 2003, and undertook additional development and refinement of the system over the winter of 2003/2004, resulting in the deployment of two camera systems in the spring of 2004 in the Hinton and Big Horn regions in the eastern foothills of the Canadian Rocky Mountains of west-central Alberta, Canada (see Figure 1).

Imaging technology, still or video, to aid researchers' understanding of animal behavior and ecology, has been available for some time. As far as we know this is the first attempt to place cameras on grizzly bear to observe their behavior and the environment through which they travel.

Selection of the study area was determined by when and where the grizzly bear were captured. Land use is primarily forestry. Predominant habitat is closed conifer forests surrounding regenerating clearcuts, minor forests, and to a lesser extent non-forest shrub, grassland, and so on. Mountainous terrain dominates the Hinton site, while the Big Horn site transitions into rolling foothills along the eastern portion. Elevations vary from 1,320 meters to approximately 2,400 meters.