In response to David Lien's letter (DCI, Feb. 27), I would like to submit the National Park Service's findings on the effect on wildlife from motorized vehicle use in Yellowstone National Park. The report is centered on winter motorized recreation.
The findings are absolutely relevant to all seasonal off-highway vehicle use, as any impacts to wildlife would be more easily recognized during winter periods when stress is greater on the animals.
"We monitored the behavioral responses of bison, elk, and trumpeter swans to motorized winter recreation by repeatedly surveying seven groomed or plowed road segments in Yellowstone National Park during December 2004 through March 2005.We sampled >2,100 interactions between vehicles and wildlife groups and used multinomial logits models to identify conditions leading to behavioral responses. Responses by these wildlife species to over-snow vehicles were relatively infrequent, short in duration, and of minor to moderate intensity, with >81% categorized as no apparent response or look/resume activities, 9% attention/alarm, 7% travel, and 3% flight or defense.
"The likelihood of an active response by bison or elk decreased as cumulative visitation increased, suggesting that these ungulates habituated somewhat to motorized recreation. There was no evidence of population-level effects to ungulates from motorized winter use because estimates of abundance either increased or remained relatively stable during three decades of motorized recreation prior to wolf colonization in 1998. Thus, we suggest that the debate regarding the effects of motorized recreation on wildlife is largely a social issue as opposed to a wildlife management issue."
A three-year study, "Response of White-Tailed Deer to Snowmobiles and Snowmobile Trails in Maine," conducted by wildlife scientists for the Maine Cooperative Wildlife Research Unit and the Maine Department of Inland Fisheries and Wildlife, revealed: "Deer consistently bedded near snowmobile trails and fed along them even when those trails were used for snowmobiling several times daily. In addition, fresh deer tracks were repeatedly observed on snowmobile trails shortly after machines had passed by, indicating that deer were not driven from the vicinity of these trails."
As a hunter and angler, my boots-on-the-ground experience concurs with the National Park Service's findings. Many studies have been done on this topic by entities including the University of Wisconsin, the Forest Wildlife Biologist of the White Mountain National Forest in New Hampshire, The University of Minnesota and others. Findings of these studies were consistent with the results of the National Park Service's report.