Response of an Alaska, U.S.A., Shrub-Tussock Community to Selected All-Terrain Vehicle Use

Abstract

Tests conducted at Wrangell–St. Elias National Park quantified the effects of all-terrain vehicle (ATV) use on a shrub-tussock community. Vehicle track depth increased significantly with increasing passes. Vehicles running on rubber tires created deeper tracks than similar vehicles mounted on continuous rubber tracks. Heavier ATVs usually produced deeper tracks than lighter vehicles. Deeper tracks resulted when vehicle use was spread over a 10-wk period during the summer than when the passes were concentrated into shorter time periods near the beginning or end of the snow-free period. Two years after completing the treatments, most of the heavier-used lanes had subsided 2 to 4 cm due to thawing of ice-rich permafrost.

Although injury occurred to shrubs continuously throughout the treatments, shrub injury rates were greatest during the first few passes by an ATV. The dwarf shrubs Empetrum nigrum and Vaccinium vitis-idaea were least affected, while the low shrub Betula nana was most susceptible to injury. The degree of sedge tussock compression and amount of organic soil exposed along the ATV tracks increased in relation to vehicle weight.