Factors Governing the Distribution and Abundance of Arctic Ground Squirrels

Werner, Jeffery R.

doi:10.14430/arctic4537

Cited by 4 publications

(2 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We propose that predation, being the most consistent explanation for population collapses, is the most likely proximate cause of local ground squirrel extinctions in the boreal forests of the SW Yukon. The principle assertions of this paper—the existence of Type II predation and an unstable critical threshold in prey density—is being tested by raising the local density of AGS above 0.7/ha in a series of experimental reintroductions into formerly occupied habitats within the boreal forest zone ( Werner, 2015 ). This study offers a practical example of how monitoring the per-capita rate of change for prey species can be used to infer the predator relationship and, by extension, the range of prey densities where mortality may be depensatory.…”

Section: Discussionmentioning

confidence: 99%

You can hide but you can’t run: apparent competition, predator responses and the decline of Arctic ground squirrels in boreal forests of the southwest Yukon

Werner

Gillis

Boonstra

2016

PeerJ

Self Cite

View full text Add to dashboard Cite

Throughout much of North America’s boreal forest, the cyclical fluctuations of snowshoe hare populations (Lepus americanus) may cause other herbivores to become entrained in similar cycles. Alternating apparent competition via prey switching followed by positive indirect effects are the mechanisms behind this interaction. Our purpose is to document a change in the role of indirect interactions between sympatric populations of hares and arctic ground squirrels (Urocitellus parryii plesius), and to emphasize the influence of predation for controlling ground squirrel numbers. We used mark-recapture to estimate the population densities of both species over a 25-year period that covered two snowshoe hare cycles. We analysed the strength of association between snowshoe hare and ground squirrel numbers, and the changes to the seasonal and annual population growth rates of ground squirrels over time. A hyperbolic curve best describes the per capita rate of increase of ground squirrels relative to their population size, with a single stable equilibrium and a lower critical threshold below which populations drift to extinction. The crossing of this unstable boundary resulted in the subsequent uncoupling of ground squirrel and hare populations following the decline phase of their cycles in 1998. The implications are that this sustained Type II predator response led to the local extinction of ground squirrels. When few individuals are left in a colony, arctic ground squirrels may also have exhibited an Allee effect caused by the disruption of social signalling of approaching predators.

show abstract

Section: Discussionmentioning

confidence: 99%

You can hide but you can’t run: apparent competition, predator responses and the decline of Arctic ground squirrels in boreal forests of the southwest Yukon

Werner

Gillis

Boonstra

2016

PeerJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…We propose that predation, being the most consistent explanation for population collapses, is the most likely proximate cause of local ground squirrel extinctions in the boreal forests of the SW Yukon. The principle assertions of this paper -the existence of Type II predation and an unstable critical threshold in prey density -is being tested by raising the local density of AGS above 0.7 / ha in a series of experimental reintroductions into formerly occupied habitats within the boreal forest zone (Werner, 2015). This study offers a practical example of how monitoring per-capita rates of change for prey species can be used to infer the predator relationship and, by extension, the range of prey densities where mortality may be depensatory.…”

Section: Study Limitationsmentioning

confidence: 99%

Peer Review #1 of "You can hide but you can’t run: apparent competition, predator responses and the decline of Arctic ground squirrels in boreal forests of the southwest Yukon (v0.1)"

Torrisi¹

2016

View full text Add to dashboard Cite

Throughout much of North America's boreal forest, the cyclical fluctuations of snowshoe hare populations (Lepus americanus) may cause other herbivores to become entrained in similar cycles. Alternating apparent competition and indirect mutualism via prey switching are the mechanisms behind this interaction. Our purpose is to document a change in the role of indirect interactions between sympatric populations of hares and arctic ground squirrels (Urocitellus parryii plesius), and to emphasize the influence of predation for controlling ground squirrel numbers. We used mark-recapture to estimate the population densities of both species over a 25-year period that covered two snowshoe hare cycles. We analysed the strength of association between snowshoe hare and ground squirrel numbers, and the changes to the seasonal and annual population growth rates of ground squirrels over time. A hyperbolic curve best describes the per capita rate of increase of ground squirrels relative to their population size, with a single stable equilibrium and a lower critical threshold below which populations drift to extinction. The crossing of this unstable boundary resulted in the subsequent uncoupling of ground squirrel and hare populations following the decline phase of their cycles in 1998. The implications are that this sustained Type II predator response led to the local extinction of ground squirrels. When few individuals are left in a colony, arctic ground squirrels may also have exhibited an Allee effect caused by the disruption of social signalling of approaching predators.

show abstract

Landscape drivers of site occupancy by remnant populations of arctic ground squirrels (Urocitellus parryii)

et al. 2021

View full text Add to dashboard Cite

Factors Governing the Distribution and Abundance of Arctic Ground Squirrels

Cited by 4 publications

References 25 publications

You can hide but you can’t run: apparent competition, predator responses and the decline of Arctic ground squirrels in boreal forests of the southwest Yukon

You can hide but you can’t run: apparent competition, predator responses and the decline of Arctic ground squirrels in boreal forests of the southwest Yukon

Peer Review #1 of "You can hide but you can’t run: apparent competition, predator responses and the decline of Arctic ground squirrels in boreal forests of the southwest Yukon (v0.1)"

Landscape drivers of site occupancy by remnant populations of arctic ground squirrels (Urocitellus parryii)

Contact Info

Product

Resources

About