Patrick J. Webber

Spatial and Temporal Variation of the Vegetation and Its Production, Barrow, Alaska

This chapter examines the factors which control the distribution of vegetation, growth-forms, species, broad productivity measures, seasonal patterns, and plant succession of the International Biological Programme (IBP) Tundra Biome site at Barrow, Alaska. It provides a framework against which the detailed physiological and modeling experiments of other production studies in this volume can be viewed. The pragmatic decisions of the program focused the experiments on a limited set of plant communities, growth-forms, and species. Since all vegetation and all species could not be modeled or studied to the depth desired, the project was designed to provide an ability to generalize spatially.

Cumulative geoecological effects of 62 years of infrastructure and climate change in ice-rich permafrost landscapes, Prudhoe Bay Oilfield, Alaska.

Many areas of the Arctic are simultaneously affected by rapid climate change and rapid industrial development. These areas are likely to increase in number and size as sea ice melts and abundant Arctic natural resources become more accessible. Documenting the changes that have already occurred is essential to inform management approaches to minimize the impacts of future activities. Here, we determine the cumulative geoecological effects of 62xa0years (1949-2011) of infrastructure- and climate-related changes in the Prudhoe Bay Oilfield, the oldest and most extensive industrial complex in the Arctic, and an area with extensive ice-rich permafrost that is extraordinarily sensitive to climate change. We demonstrate that thermokarst has recently affected broad areas of the entire region, and that a sudden increase in the area affected began shortly after 1990 corresponding to a rapid rise in regional summer air temperatures and related permafrost temperatures. We also present a conceptual model that describes how infrastructure-related factors, including road dust and roadside flooding are contributing to more extensive thermokarst in areas adjacent to roads and gravel pads. We mapped the historical infrastructure changes for the Alaska North Slope oilfields for 10 dates from the initial oil discovery in 1968-2011. By 2010, over 34% of the intensively mapped area was affected by oil development. In addition, between 1990 and 2001, coincident with strong atmospheric warming during the 1990s, 19% of the remaining natural landscapes (excluding areas covered by infrastructure, lakes and river floodplains) exhibited expansion of thermokarst features resulting in more abundant small ponds, greater microrelief, more active lakeshore erosion and increased landscape and habitat heterogeneity. This transition to a new geoecological regime will have impacts to wildlife habitat, local residents and industry.

Damage and Recovery of Tundra Vegetation

This paper makes a series of broad recommendations concerning the understanding of damage and recovery of tundra vegetation. It deals primarily with arctic vegetation and with principles rather than specific recommendations or instructions for restoration. Actual procedures for restoration or revegetation, although practised, are still in their experimental stages. Despite this lack of established methods in tundra vegetation restoration, much can be done to help offset some of the worst effects of the present surge of economic development that is occurring in certain sectors of the Arctic. First, a rational assessment of types and extent of damage that is likely to accrue from different kinds and degrees of impact should be attempted, based on existing experience and theory. This should be accompanied by similar assessments of degrees and rates of recovery.

Use of Geobotanical Maps and Automated Mapping Techniques to Examine Cumulative Impacts in the Prudhoe Bay Oilfield, Alaska

A comprehensive approach to the problem of examining impacts on tundra landscapes is presented, using the Prudhoe Bay oilfield as a model. Development of the oilfield is documented, utilizing a series of ‘historical’ disturbance maps for the period 1949–83. Cumulative development of the entire field was mapped at a scale of 1:24,000, and an intensely developed portion of the field was mapped at 1:6,000, using an integrated geobotanical and historical disturbance map (IGHDM). The IGHDM data were automated, and a series of maps was made which depict a variety of information—including geobotany of the area as of 1949, and the historical sequence of development from 1968 to 1983.

PINGOS OF THE PRUDHOE BAY REGION, ALASKA

Two distinctive types of small dome-shaped hills occur in the Prudhoe Bay region. One type has small basal diameters, steep side slopes, and occurs primarily in drained thaw-lake basins; the other type consists of mounds of larger diameter and commonly occurs outside modern lake basins. The U.S. Army Cold Regions Research and Engineering Laboratory drilled three of the mounds including one broad-based mound and encountered massive ice in all of them. It is thus likely that all of the steep-sided mounds and at least the larger broad-based mounds are pingos. It is clear that the largest of the broad-based mounds are neither dunes, unmodified remnants, nor highly eroded steep-sided pingos of the type common in the region today. Discriminant analysis of topographic-map data indicates that mean slope and length of the longest axis are the clearest discriminators between the two groups of mounds. The broad-based mounds are limited to older surfaces in the region and are thus likely to be quite old (< 12,000 yr). Explanations for the large size of many of the broad-based mounds and their occurrence outside lake basins will have to await detailed drilling studies.

GEOBOTANICAL AND ECOLOGICAL OBSERVATIONS AT TWO LOCATIONS IN THE WEST-CENTRAL SIBERIAN ARCTIC

Preliminary results of a field excursion to the Siberian Arctic in July 1976 are reported. The excursion was part of a bilateral exchange of American scientists to the Institute for Extreme North Agricultural Research at Norilsk. Two field sites were visited: Lake Ayan (ca. 69?N, 94030E) in the mountainous Putorana Plateau 200 km east of Norilsk; and Pura River (ca. 72?30N, 86?E) in the rolling, moderately drained tundra of the western part of the Taimyr Peninsula. The ecosystems at each site are described, emphasizing associations between landforms, plant communities, and fauna. Generalized profiles illustrate the landform/plant community relations. The main plant species of each community are tabulated. Both study sites are important wildlife habitats. Lake Ayan is surrounded by Larix dahurica forest, Snow-sheep (Ovis nivicola) live above the for