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No. 485: A review on vegetation damages caused by anthropogenic disturbances in the terrestrial Arctic

Kyhn, L.A., Boertmann, D., Aastrup, P. & Mosbech, A. 2022. A review on vegetation damages caused by anthropogenic disturbances in the terrestrial Arctic. - with recommendations for best practices to minimize vegetation damage from driving with heavy equipment. Aarhus University, DCE – Danish Centre for Environment and Energy,66 pp. Scientific Report No. 485. http://dce2.au.dk/pub/SR485.pdf.

Summary

This report reviews the knowledge on vegetation and terrain damage from anthropogenic activities in the Arctic based on information from Alaska, Canada and the seismic surveys carried out in Jameson Land, East Greenland in the 1980ies based on peer-reviewed literature as well as on “grey” literature such as scientific advisory reports.

The present report gives an overview of the most significant elements of the Arctic in the context of vegetation and terrain damage: Permafrost, the active layer above the permafrost, the vegetation and the terrain, and it is underlined that an intact vegetation cover is the key to maintaining the thermal balance between the active layer and the permafrost, which is the most crucial aspect for restoration.

This is followed by an overview of vegetation damages and the effects on the deeper layers below – the active layer and especially the permafrost and on hydrology. Different activities (incl. oil spills) and their potential for vegetation damages are described, with focus on driving and transport of heavy equipment.

Methods for assessing vegetation damages and ways to re-establish vegetation are briefly described.

The report reviews the authority regulation related to protection of vegetation in Arctic Canada and Alaska, followed by a description of the previous regulation in Greenland when seismic surveys took place in Jameson Land, East Greenland in 1980ies. The regulation then was based on background studies in the affected area and on the regulation experiences from Canada and Alaska.

It is concluded, that no serious long-term effects of the winter seismic surveys in Jameson Land have been found in terms of vegetation cover or erosion. In that sense, the regulation was a success. Some of the main concerns about the wet terrain and vegetation types are not confirmed, while the dry heaths with frost sensitive species like Cassiope tetragona turned out to be more sensitive with damages still visible after 30 years, a fact not anticipated or considered in the regulation.

The lessons learned then are summarised and together with the Canadian and Alaskan regulation give rise to recommendation of some new best practices to avoid vegetation damages from use of heavy vehicles in Greenland.

The key factors to avoid or minimize vegetation damages in winter are the depth of the snow layer and freeze up of the ground and soil beneath the snow, and it is recommended that activities with heavy vehicles cannot be initiated until:

  • The ground is frozen, i.e. the temperature shall be -5 °C at 30 cm soil depth,
  • Snow depth is at least 25 cm in all terrains.

However, local conditions may change these figures.

Regarding summer seismic surveys on land, DCE and Greenland Institute of Natural Resources (GINR) generally recommend that they are avoided and carried out in winter instead, when the terrain is frozen and snow-covered.

Finally, the report identify some relevant research needs to be addressed in relation to regulation of activities with heavy vehicles, such as seismic surveys:

  • In areas where activities are planned: Vegetation mapping including ground-truthing of vegetation types, occurrence of red-listed plant species, mapping of snow depths and annual freezing of the active layer,
  • The sensitivity of various high Arctic vegetation types to driving activities both summer and winter. In the latter case especially under different snow regimes including compaction of snow.