Fractal measures of female caribou movements

Abstract

Understanding caribou movement during short-term searches for specific habitats, potential mates, and refugia against predators can help resolve ecological questions on how individual caribou perceive their environment. We used measures of fractal dimension and standardized pathlength to compare the movement pathways of female caribou. Satellite telemetry locations were collected over a 2-year study, March 1994 to mid-May 1996, for a caribou population in central Saskatchewan living in the southern boreal forest. Female caribou displayed more random searching behaviour during winter and more regular dispersal movements during early winter/spring and autumn periods. Females with a calf showed no difference in movement pattern (fractal dimension) relative to females without a calf but their standardized path length was shorter. We discuss the advantages of using fractal dimension as a measure of the tortuosity of movement pathways and how changes in fractal dimension over a range of scales can define domains of consistent ecological processes.

Keywords

• caribou movement
• caribou behaviour
• fractal dimension
• hierarchy
• landscape
• movement pathway