Long‐term recovery patterns of arctic tundra after winter seismic exploration

Abstract

Abstract. In response to the increasing global demand for energy, oil exploration and development are expanding into frontier areas of the Arctic, where slow-growing tundra vegetation and the underlying permafrost soils are very sensitive to disturbance. The creation of vehicle trails on the tundra from seismic exploration for oil has accelerated in the past decade, and the cumulative impact represents a geographic footprint that covers a greater extent of Alaska's North Slope tundra than all other direct human impacts combined. Seismic exploration for oil and gas was conducted on the coastal plain of the Arctic National Wildlife Refuge, Alaska, USA, in the winters of 1984 and 1985. This study documents recovery of vegetation and permafrost soils over a two-decade period after vehicle traffic on snow-covered tundra. Paired permanent vegetation plots (disturbed vs. reference) were monitored six times from 1984 to 2002. Data were collected on percent vegetative cover by plant species and on soil and ground ice characteristics. We developed Bayesian hierarchical models, with temporally and spatially autocorrelated errors, to analyze the effects of vegetation type and initial disturbance levels on recovery patterns of the different plant growth forms as well as soil thaw depth. Plant community composition was altered on the trails by species-specific responses to initial disturbance and subsequent changes in substrate. Long-term changes included increased cover of graminoids and decreased cover of evergreen shrubs and mosses. Trails with low levels of initial disturbance usually improved well over time, whereas those with medium to high levels of initial disturbance recovered slowly. Trails on ice-poor, gravel substrates of riparian areas recovered better than those on ice-rich loamy soils of the uplands, even after severe initial damage. Recovery to pre-disturbance communities was not possible where trail subsidence occurred due to thawing of ground ice. Previous studies of disturbance from winter seismic vehicles in the Arctic predicted short-term and mostly aesthetic impacts, but we found that severe impacts to tundra vegetation persisted for two decades after disturbance under some conditions. We recommend management approaches that should be used to prevent persistent tundra damage.

Recovery of Tundra Vegetation Three Decades after Hydrocarbon Drilling with and without Seeding of Non-Native Grasses + Supplementary Appendices (See Article Tools)

“…Seed sources for many sump colonizers likely originate in these naturally disturbed areas (Cargill and Chapin, 1987). The persistence of distinct plant communities on sump caps after three decades of recovery is consistent with results of Johnstone and Kokelj (2008) in the MDR and other studies demonstrating slow recovery of tundra vegetation following industrial disturbance that span multiple decades (Harper and Kershaw, 1996;Forbes et al, 2001;Jorgenson et al, 2010;Rydgren et al, 2011). In contrast, other research in the MDR has documented rapid rates of vegetation recolonization and recovery following disturbances of tundra by fire, thaw slumps, drainage of lakes, and abandonment of gravel quarries (Lantz et al, 2009(Lantz et al, , 2010(Lantz et al, , 2013Marsh et al, 2009).…”

“…Sites underlain by ice-rich permafrost, or perennially frozen ground, can thaw and subside when the vegetation is removed or even compacted (Bliss and Wein, 1972;Burn and Kokelj, 2009;Jorgenson et al, 2010). Thawing of permafrost and the resulting changes in surface drainage alter soil conditions for plant growth, while at the same time plant community composition and structure affect permafrost stability through surface cover or effects on snow interception Kokelj et al, 2010).…”

“…Thawing of permafrost and the resulting changes in surface drainage alter soil conditions for plant growth, while at the same time plant community composition and structure affect permafrost stability through surface cover or effects on snow interception Kokelj et al, 2010). Once initiated, these interactions can be sustained over several years or decades and can substantially alter trajectories of vegetation recovery (Jorgenson et al, 2010;Lantz et al, 2013). Thus, early interventions that can alter the interacting effects of vegetation and permafrost thaw on disturbance recovery are of substantial interest for managing the impacts of oil and gas extraction in the North.…”

Linear disturbances on discontinuous permafrost: implications for thaw-induced changes to land cover and drainage patterns

“…depend on the degree of permafrost thaw (Jorgenson et al 2010a). Such consequences may be particularly important along the southern margins of discontinuous permafrost where permafrost is relatively thin (∼10 m) (Burgess and Smith 2000) and ground thermal regimes are vulnerable to disturbance.…”

Potential conflict between future development of natural resources and high-value wildlife habitats in boreal landscapes

“…Furthermore, increases in graminoid vegetation in reclaimed industrial lands could provide wild sheep with preferred forage (MacCullum and Geist 1992) given their forage preference toward graminoids year round (Seip and Bunnell 1985;Walker et al 2007). Difficulties of restoring shrub habitats in harsh environments (Smyth 1997;Jorgenson et al 2010;Sloan and Jacobs 2013) might discourage mountain goats from using reclaimed lands, especially in winter when their dependence on woody forage increases (Adams and Bailey 1983;Fox and Smith 1988 Fig. S5.2).…”