Human Impact Study
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Reaction to Vehicles
A major component of the study was to measure the bears' reactions to tundra vehicles. The research team designed "approach experiments" to determine at what distance, if any, polar bears are disturbed by the vehicles that lumber across the tundra. The scientists tested three different types of approaches to measure the bears' reactions: direct, indirect, and indirect with sound.
Over a two-year period, the scientists recorded 186 approaches (68 in 2003 and 118 in 2004). In each approach, a driver drove a tundra vehicle toward a stationary bear—that is, one lying, sitting or standing—at a constant speed while a volunteer taped the bear's behavior with a digital camcorder. The researchers ended each approach if the bear responded or if they came within a distance of 17 meters. The team defined a response as "any sudden movement or change in whole body position or behavior at the time of approach."
Sound Experiments
Waterman, Roth, and Eckhardt also studied the effects of human-induced noise on a polar bear's behavior. In 2003, they measured the average noise levels produced by visitors on tourist vehicles during their first close encounter with a bear. They then used this decibel level to study its effect on the bears.
"In this experiment, we would approach a bear indirectly in a tundra vehicle until we were alongside it," says Waterman. "Once the vehicle had stopped, we would turn off the engine and roll down a window on the side facing the bear. Then we used speakers to play a random selection of one of four recordings, each eight seconds in length—a control recording and three with human voices."
The team ran the same experiment with the same bears on consecutive days to investigate whether the bears would habituate to human-induced noises.
A major component of the study was to measure the bears' reactions to tundra vehicles. The research team designed "approach experiments" to determine at what distance, if any, polar bears are disturbed by the vehicles that lumber across the tundra. The scientists tested three different types of approaches to measure the bears' reactions: direct, indirect, and indirect with sound.
Over a two-year period, the scientists recorded 186 approaches (68 in 2003 and 118 in 2004). In each approach, a driver drove a tundra vehicle toward a stationary bear—that is, one lying, sitting or standing—at a constant speed while a volunteer taped the bear's behavior with a digital camcorder. The researchers ended each approach if the bear responded or if they came within a distance of 17 meters. The team defined a response as "any sudden movement or change in whole body position or behavior at the time of approach."
Sound Experiments
Waterman, Roth, and Eckhardt also studied the effects of human-induced noise on a polar bear's behavior. In 2003, they measured the average noise levels produced by visitors on tourist vehicles during their first close encounter with a bear. They then used this decibel level to study its effect on the bears.
"In this experiment, we would approach a bear indirectly in a tundra vehicle until we were alongside it," says Waterman. "Once the vehicle had stopped, we would turn off the engine and roll down a window on the side facing the bear. Then we used speakers to play a random selection of one of four recordings, each eight seconds in length—a control recording and three with human voices."
The team ran the same experiment with the same bears on consecutive days to investigate whether the bears would habituate to human-induced noises.