Approaching ATVs Send Elk into Hiding
Even when two kilometres away, someone riding an all-terrain vehicle (ATV) can cause elk to head for cover. By the time the machine approaches within 100 m, there’s an 80% chance that elk will have left the vicinity of roads and trails. Other elk decide to freeze instead of flee, particularly when topography and vegetation can conceal them. It remains for further research to find out how much the energy used to avoid motorized recreationists costs elk in their reproduction and survival.
Scientists conducted the study of female elk reacting to ATVs near La Grande, Oregon in the Wallowa Whitman National Forest. On rolling bench lands vegetated with bunchgrass and conifers, 1450 fenced hectares confine wild Rocky Mountain elk.
During quiet mornings at this site, elk moved only short distances and dispersed throughout the landscape. But on mornings that ATVs passed through at speeds of 8 to 20 km an hour, the animals travelled much farther and congregated in concealed areas. After the third consecutive day with ATVs in the vicinity the elk sought less remote hiding places, but also kept close to areas out of sight from roads. The animals reverted to their normal patterns once people stayed out of the enclosure for nine days.
The elk recognized that roads bring disruptions from people and got particularly spooky when standing within 20 m of a road. Once they were half a kilometre away from a travelled route, the ungulates remained less perturbed about approaching ATVs.
For this experiment researchers developed a statistical technique for analyzing data collected from elk and ATVs equipped with global positioning systems (GPS). This enabled the study to gather, for the first time, comprehensive measures of the extent to which recreational vehicles disturb wildlife.
Haiganoush K. Preisler, Alan Ager and Michael J. Wisdom. 2006. Statistical methods for analysing responses of wildlife to human disturbance. Journal of Applied Ecology. 43(1): 164-172.