• Off-road recreational vehicles (excluding motorcycles) are being used in more than half of all possible national park units.(1)
• Thirty-eight National Parks – over a third – acknowledge serious damage to resources including the creation of long-lasting tire tracks and wheel ruts, disturbance and harm to endangered wildlife, introduction of exotic species and damage to vegetation.(2)
• Over 30,434 miles of four-wheel drive routes are legally open to off-road vehicles.(3)
• In 1997, there were an estimated 54,500 ORV-related injuries nationwide.(4)

ORVs Ruin Hunting Grounds

Because it is easier than walking, increasing numbers of people are hunting from their ORV rather than on foot. The noise and smell of an ORV can alert game animals from a long way off so the odds of seeing game from an ORV are much reduced. And, that same noise and smell that is chasing game away from the ORV user is also chasing them away from any other hunters in the area as well. This can create very hard feelings among hunters who used stealth and stalking skills to get into prime habitat only to have the deer and elk scared off by ORVs.

Because ORVs can access terrain that other motorized vehicles cannot, some riders are making improper use of that advantage and creating an extensive network of new roads and trails in areas that were previously roadless. This causes increased impacts to vegetation and soils. It also creates travelways that tempt other recreationists to follow, resulting in those faint tracks through the meadow becoming a full-blown road. The elk and deer in that area are then subject to year-round disturbance. Big-game hunters should be aware that half a dozen studies have clearly shown that elk avoid vehicle activity associated with a road or ORV trail. Other interesting tidbits from these studies show that:

• Elk use declines in areas adjacent to roads for distances ranging from 0.25 to 1.8 miles, depending on the amount of traffic, the quality of the road and the density of the vegetation and topographic cover next to the road. In general, greater traffic flow on higher quality unpaved roads produces a larger area of elk avoidance.(5)
• Slow-moving vehicles on primitive roads and trails are more disturbing to elk than fast-moving vehicles on a highway.(6)
• As road and ATV trail density increases in an area, the quality and size of the elk habitat declines significantly. This eventually affects the quality and size of the elk population. A road density of three linear miles of road per square mile of land seriously reduces the value of that area for elk, and a road density of six linear miles per square mile can reduce elk occurrence to zero.(7)
• When vehicle use during hunting season reaches a certain threshold, elk will abandon that area completely and head for inaccessible areas such as private land or wilderness areas. The result is that road and trail proliferation and persistent use of vehicles during hunting season is cutting down all hunters’ chances of harvesting that elk and it is degrading the habitat of the very animal they are hunting.(8)

Soil Displacement

The use of ORVs often causes substantial erosion of the soils on which they travel. Soil erosion can expose the roots of plants. Displaced soil can bury downslope vegetation. Displaced soil typically finds its way into waterways, which can negatively impact aquatic species.

Soil Compaction

Primarily because of their weight, ORVs tend to compact the soils on which they are driven. Compacted soil can cause damage to surface vegetation, disrupt nutrient cycling and negatively affect the ability of roots to penetrate the soil.(9) Additionally, it negatively impacts the population dynamics of organisms that live underground through both direct mortality and subterranean habitat destruction.(10) The plants and animals that suffer as a result of such impacts include organisms that play critical roles in the maintenance of a healthy ecosystem; organisms that fix nitrogen, transport micronutrients, break down organic matter and so forth.(11)

Pollution

Off-road vehicles are allowed to pollute our air, water, and soil. Areas where ORVs are operated in large numbers experience severe air pollution problems.(12) Much of the pollution created by ORVs eventually ends up settling on the soil and water and on the snow during winter months. This can harm soils, soil organisms and plants, and aquatic habitats.(13) ORVs also leak fuel, oil, antifreeze, and other dangerous chemicals.(14)

Vegetation Damage

Off-road vehicles harm vegetation directly through trampling, soil compaction, and air, soil, and water pollution.(15) The results are devastating: fewer plants, reduced plant cover, lowered plant diversity and disruptions to plant successional and nutrient cycling processes. (16) ORVs frequently trample, crush, uproot, and otherwise damage plants and their root systems.(17) These disturbances lead the way to another problem: the invasion of exotic and noxious weed species.(18)

Wildlife Damage

Off-road vehicles are responsible for four main types of impacts to wildlife: direct mortality, disturbance, noise, and habitat impacts. Collisions with wildlife often prove fatal to animals. For most wildlife, exposure to the noise and sight of ORVs results in increased stress levels and energy expenditures.(19) ORV use fragments available wildlife habitat, dramatically reducing suitable homes for many wildlife species.(20)

The exposed terrain that results from the establishment of ORV trails engender unnatural edge effects which, in turn, produce microclimate alterations such as changes in moisture, sunlight, soil and air temperature gradients, wind speed and noise levels.(21) The end result is the proliferation of invasive species and the disruption of local food chains.

Sources:
(1) - (4) “Off-the-Track: America’s National Parks Under Siege.” Bluewater Network. 1999. 18 June 2003 <http://www.bluewaternetwork.org/reports/rep_pl_offroad_offtrack.pdf>.
(5) - (8) “Hunting With ATVs – Responsibility or Regulation?” Colorado Bureau of Land Management. Updated 11 June 2001. 18 June 2003 <http://www.co.blm.gov/gra/gra-atvethic.htm>.
(9) - (11), (15) - (18), (21) “Out of Control: The Impacts of Off-Road Vehicles and Roads on Wildlife and Habitat in Florida’s National Forests.” Defenders Of Wildlife. August 2002. 18 June 2003 <http://www.defenders.org/habitat/florvs/ORVmain.pdf>.
(12) - (14), (19), (20) “Outdoor Wreckreation.” The Lands Council. 18 June 2003 <http://www.landscouncil.org/fwatch/orv.htm>.