- 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.