Successful and Not-so-Successful Tundra Revegetation Techniques.

As Alaska’s North Slope oilfields matured, it became apparent that revegetation of abandoned sites would be required. Early research into appropriate methods began in 1985 with a study of Arctophila fulva (pendantgrass), a grass that grows well in shallowly-flooded areas. Since then, many methods have been tried, including fertilizing with Phosphorus only, seeding with various grasses to identify species that could provide rapid cover without permanently excluding other species, staking willows, collecting indigenous seed, seeding with Carex aquatilis (water sedge), transplanting tundra plugs, transplanting tundra sod, and allowing for natural colonization alone. Experiments were conducted to test various “lifts” of gravel remaining on the tundra to see if vegetation cover was affected by the depth of gravel. A seed nursery was established and a test placing pre-vegetated mats of Carex aquatilis was recently conducted. Each site is approached on a case-by case basis, but the approach is based on collective experience from previous sites. As of yet, no across-the-board analysis has been performed to compare similarly-treated sites. Therefore, conclusions about what has been successful, and what has not, may not be transferable to every site encountered in the future. Treatments and monitoring methods have evolved over the last 20 years, especially seeding rates of native-grass cultivars and changing from a quadrat monitoring method to use of a laser pointer for identifying plants along transects. This can make comparisons between treatments at various sites difficult. The native soils are very low in nutrients and regular soil testing revealed similar results across a wide variety of sites. Soil testing is no longer routinely undertaken except where salinity or other unique problems are suspected. Today, monitoring is conducted for 10 years, although some sites require extensions to the performance period. Sites that are considered successful have 10% live indigenous cover, a performance standard developed in the last ten years that indicates the site is on a trajectory toward vegetation cover similar to the surrounding tundra in the long term (decades).