Arctic ground squirrels Urocitellus parryii as drivers and indicators of change in northern ecosystems

Abstract

Global warming and increasing human activity are altering northern ecosystems. In these strongly seasonal environments, small herbivorous mammals may have a significant role in determining the trajectory of ecosystem transitions from one state to another. Arctic ground squirrels Urocitellus parryii are a key component of northern terrestrial food webs and are considered ecosystem engineers, exerting a large impact on their habitat through bioturbation. We review and synthesize diverse information about current and past distribution and density of arctic ground squirrels, their physiology and ecological interactions with other species. Factors that appear to affect the distribution and abundance of arctic ground squirrels include increasing temperatures, changes in flooding probability, permafrost thaw, shifting phenology, habitat change, new predators and invasive diseases. Increases in the distribution and density of arctic ground squirrels in northern latitudes and high altitudes could accelerate ecosystem change through facilitation of disturbance‐tolerant species, while decreases in southern and milder climates could remove an important agent of disturbance and prey item. Despite their pervasive ecological influence throughout most of their range, arctic ground squirrels are underrepresented in ecological research, based on a comparison of the number of publications about arctic ground squirrels with the number about other species of the same genus, and about other arctic herbivores. The widespread distribution of arctic ground squirrels, along with their potential to exacerbate and alter trajectories of ecosystem change under global warming, makes them a valuable indicator of ecosystem change and therefore a candidate for increased monitoring.

Distribution and occupancy of wolverines on tundra, northwestern Alaska

“…In NPR‐A there are 3 key factors with potential to influence wolverine populations: climate change, industrial development, and hunting and trapping. Alaska's climate is warming at twice the rate as the rest of North America and greater increases in warming in the northernmost parts of the state (Chapin et al ) are bringing a suite of ecological changes that may affect wolverines (Tape et al , Wheeler and Hik , Tape et al , Magoun et al ). Additionally, plans for oil, gas, mining, and road development means potential for increasing infrastructure in NPR‐A (U.S. Bureau of Land Management [BLM] 2017).…”

How will the greening of the Arctic affect an important prey species and disturbance agent? Vegetation effects on arctic ground squirrels

“…Likely future trends in forb cover are less clear than for shrubs and graminoids (Elmendorf et al 2012). Trends in forb cover at the level of the functional group have shown no major change with experimental warming either in wet or dry sites (Wahren et al 2005) and no consistent temporal trends in a largescale analysis of tundra responses to warming (Elmendorf et al 2012). This study suggests the contingencies which determine success of forbs under changing ecological structure of communities are likely to strongly influence arctic ground squirrel success.…”

Use of Arctic ground squirrels (Urocitellus parryii) by brown bears (Ursus arctos)

“…Arctic ground squirrels are an important herbivore in northern ecosystems, and their distribution and density are predicted to change with global warming (Wheeler and Hik 2013). Recent observations of brown bears in the Canadian Arctic Archipelago suggest a northward range expansion (Doupe et al 2007, AED unpubl.…”