Cumulative impacts of a gravel road and climate change in an ice-wedge-polygon landscape, Prudhoe Bay, Alaska

Abstract

Environmental impact assessments for new Arctic infrastructure do not adequately consider the likely long-term cumulative effects of climate change and infrastructure to landforms and vegetation in areas with ice-rich permafrost. This is due in part to lack of long-term environmental studies that monitor changes after infrastructure is built. This case study examines long-term (1949–2020) climate- and road-related changes in a network of ice-wedge polygons, Prudhoe Bay Oilfield, Alaska. We studied four trajectories of change along a heavily traveled road and a relatively remote site. During 20 years prior to oilfield development, the climate and landscapes changed very little. During 50 years after development, climate-related changes included increased numbers thermokarst ponds, changes to ice-wedge-polygon morphology, snow distribution, thaw depths, dominant vegetation types, and shrub abundance. Road dust strongly affected plant-community structure and composition, particularly small forbs, mosses, and lichens. Flooding increased permafrost degradation, polygon center-trough elevation contrasts, and vegetation productivity. It was not possible to isolate infrastructure impacts from climate impacts, but the combined datasets provide unique insights into the rate and extent of ecological disturbances associated with infrastructure-affected landscapes under decades of climate warming. We conclude with recommendations for future cumulative impact assessments in areas with ice-rich permafrost.

The spatial and temporal influence of infrastructure and road dust on seasonal snowmelt, vegetation productivity, and early season surface water cover in the Prudhoe Bay Oilfield

“…Arctic regions are experiencing rapid change due to cumulative effects caused by climate change and the expansion of infrastructure driven primarily by industrial development related to resource extraction (NRC 2003;AMAP, 2007;Walker et al 2022). Oil and gas exploration and development, in particular, has led to the spread of infrastructure in many areas of the circumpolar Arctic over the last five decades (Kumpula et al, 2012;Raynolds et al, 2014Raynolds et al, , 2020Walker et al, 2022).…”

“…Arctic regions are experiencing rapid change due to cumulative effects caused by climate change and the expansion of infrastructure driven primarily by industrial development related to resource extraction (NRC 2003;AMAP, 2007;Walker et al 2022). Oil and gas exploration and development, in particular, has led to the spread of infrastructure in many areas of the circumpolar Arctic over the last five decades (Kumpula et al, 2012;Raynolds et al, 2014Raynolds et al, , 2020Walker et al, 2022). Areas like the Prudhoe Bay Oilfield in Alaska (Figure 1a) are host to many types of infrastructure, ranging from paved and gravel roads, airports, stores, and other service facilities, to pipelines, processing plants, drill rigs, gravel pits and pads, and associated features of oil and gas production (Raynolds et al, 2014).…”

“…Infrastructure actively influences the distribution and redistribution of snow by creating barriers that act like snow fences, leading to modified snow depths and snow-melt patterns (Fortier et al 2011). Previous studies have shown that snow along roads and on road embankments can disappear earlier compared to snow in the surrounding area, leading to earlier soil thaw and vegetation green-up near roads (Benson et al, 1975;Walker and Everett, 1987;Walker et al, 2022, Chen et al, 2020. In winter, roadside snow drifts develop along the margins of the elevated roads.…”

“…Thus, the snowdrifts insulate the soils, keeping the underlying tundra relatively warm during winter. Dust-covered roadside drifts also melt out earlier than areas distant from the roads, contributing to early-summer flooding, warmer summer soil temperatures, thicker active layers near roads, and enhanced thermokarst (Walker et al, 2022). These snow-free and often-flooded roadside areas attract wildlife, including many waterbirds before nesting (Walker and Everett, 1987;Truett et al, 1997).…”

“…The high pH of the loess-derived soils (Everett and Parkinson 1977) promotes a relatively rich local flora with abundant basophilous plant species (Walker, 1985;Walker and Everett, 1991). However, extreme amounts of dust near roads cause reduced species diversity and vegetative cover, particularly of small forbs, mosses, and lichens (Walker et al, 2022). Remote sensing has been a frequently used tool to study snow cover, snow water equivalent (SWE) and other snow properties in the high and mid latitudes.…”