The Effects of Winter Seismic Trails on Tundra Vegetation in Northeastern Alaska, U.S.A.

Felix, Nancy; Raynolds, Martha

The effects of winter seismic trails on tundra vegetation were studied on the Coastal Plain of the Arctic National Wildlife Refuge. Seismic exploration occurred during the winters of 1984 and 1985. Thirty-four permanent study plots were established the following summers, representing the range of disturbance which occurred in each of seven major vegetation types. Plots were visited two of the first three summers after disturbance. At each plot plant cover was measured using a point frame, disturbance characteristics were recorded, and ground surface elevations were surveyed. Plant cover was lower on most disturbed plots than on their adjacent controls, with decreases as high as 87% the first summer following disturbance. The species most sensitive to disturbance were evergreen shrubs, followed by willows, tussock sedges, and lichens. Willow height in riparian shrubland plots was significantly reduced by 5 to 11 cm (from an average of 16 cm, p < 0.05). Little recovery of plants occurred in the second or third summers after disturbance; only four plots in river floodplain habitats (Dryas terrace and riparian shrubland) showed improvements in cover of a few species. Track depressions ranging from 5 to 15 cm occurred at three plots in moist sedge--shrub tundra and increased significantly (p < 0.05) at one plot between the first and third summers following disturbance. Continuation of this study will provide information on the long-term impacts and recovery rates of winter seismic trails.

The Effects of Winter Seismic Trails on Tundra Vegetation in Northeastern Alaska, U.S.A.

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