Evidence for source–sink dynamics in a regional population of arctic ground squirrels (Urocitellus parryii plesius)
Scott A. Donker A and Charles J. Krebs A B
+ Author Affiliations
- Author Affiliations
A Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, B.C. V6T 1Z4, Canada.
B Corresponding author. Email: krebs@zoology.ubc.ca
Wildlife Research 39(2) 163-170 https://doi.org/10.1071/WR11167
Submitted: 23 September 2011 Accepted: 24 January 2012 Published: 26 March 2012
Abstract
Context: Variable demographic rates can manifest themselves between habitat types in the form of source–sink dynamics where populations in sink habitats would not exist without the addition of migrants from source habitats.
Aims: Arctic ground squirrels (Urocitellus parryii pleisus (Osgood, 1900)) occupy a large geographic area in northern Canada and live in a variety of habitat types, including boreal forest, low-elevation meadows and alpine meadows, providing an opportunity to investigate the possible existence of source–sink dynamics.
Methods: We hypothesised that arctic ground squirrels in the south-western Yukon exhibit demographic characteristics indicative of source–sink dynamics. Boreal forest habitat could be a sink in spite of previous high squirrel densities, whereas meadows could be a source. We investigated this by mark–recapture live-trapping and radio-telemetry.
Key Results: In the boreal forest in the Kluane region, we found reduced recruitment, reduced population growth rates (λ), and reduced survivorship for radio-collared individuals that moved from low-elevation meadows into the boreal forest. There was no evidence from radio-collared juveniles of dispersal from high-density ground squirrel populations in alpine meadows down into boreal forest.
Conclusions: Boreal forest is a sink habitat for arctic ground squirrels. Source–sink dynamics observed between low-elevation meadow and boreal forest habitats appear to result from increased predation pressure in the boreal forest. The result has been a near extirpation of boreal forest arctic ground squirrels in the Kluane region since 1998.
Implications: Because the source areas of low-elevation meadows occupy only 7–9% of the lowland habitat, recolonisation of boreal forest sites has been very slow. Whereas alpine populations remain high in 2011, boreal forest populations remain near zero. Alpine populations do not appear to be a source for the boreal forest.
Additional keywords: habitat-specific demography, Yukon Urocitellus parryii plesius.
References
Boonstra, R., Boutin, S., Byrom, A. E., Karels, T. J., Hubbs, A. H., Stuart-Smith, K., Blower, M., and Antpoehler, S. (2001). Chapter 9: the role of red squirrels and arctic ground squirrels. In ‘Ecosystem Dynamics of the Boreal Forest: The Kluane Project’. (Eds C. J. Krebs, S. Boutin, and R. Boonstra.) pp. 179–214. (Oxford University Press: New York.)Boutin, S., Krebs, C. J., Boonstra, R., Dale, M. R. T., Hannon, S. J., Martin, K., Sinclair, A. R. E., Smith, J. N. M., Turkington, R., Blower, M., Byrom, A., Doyle, F. I., Doyle, C., Hik, D., Hofer, L., Hubbs, A., Karels, T., Murray, D. L., Nams, V., O’Donoghue, M., Rohner, C., and Schweiger, S. (1995). Population changes of the vertebrate community during a snowshoe hare cycle in Canada’s boreal forest. Oikos 74, 69–80.
| Population changes of the vertebrate community during a snowshoe hare cycle in Canada’s boreal forest.Crossref | GoogleScholarGoogle Scholar |
Brawn, J. D., and Robinson, S. K. (1996). Source–sink population dynamics may complicate the interpretation of long-term census data. Ecology 77, 3–12.
| Source–sink population dynamics may complicate the interpretation of long-term census data.Crossref | GoogleScholarGoogle Scholar |
Brooks, R. P. (1997). Improving habitat suitability index models. Wildlife Society Bulletin 25, 163–167.
Bruna, E. M. (2003). Are plant populations in fragmented habitats recruitment limited? Tests with an amazonian herb. Ecology 84, 932–947.
| Are plant populations in fragmented habitats recruitment limited? Tests with an amazonian herb.Crossref | GoogleScholarGoogle Scholar |
Byrom, A. E., and Krebs, C. J. (1999). Natal dispersal of juvenile arctic ground squirrels in the boreal forest. Canadian Journal of Zoology 77, 1048–1059.
| Natal dispersal of juvenile arctic ground squirrels in the boreal forest.Crossref | GoogleScholarGoogle Scholar |
Byrom, A. E., Karels, T. J., Krebs, C. J., and Boonstra, R. (2000). Experimental manipulation of predation and food supply of arctic ground squirrels in the boreal forest. Canadian Journal of Zoology 78, 1309–1319.
Caraco, T., Martindale, S., and Pulliam, H. R. (1980). Avian flocking in the presence of a predator. Nature 285, 400–401.
| Avian flocking in the presence of a predator.Crossref | GoogleScholarGoogle Scholar |
Carl, E. A. (1971). Population control in arctic ground squirrels. Ecology 52, 395–413.
| Population control in arctic ground squirrels.Crossref | GoogleScholarGoogle Scholar |
Caudill, C. C. (2003). Empirical evidence for nonselective recruitment and a source sink dynamic in a mayfly metapopulation. Ecology 84, 2119–2132.
| Empirical evidence for nonselective recruitment and a source sink dynamic in a mayfly metapopulation.Crossref | GoogleScholarGoogle Scholar |
Dias, P. C. (1996). Sources and sinks in population biology. Trends in Ecology & Evolution 11, 326–330.
| Sources and sinks in population biology.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3M7itFCrtQ%3D%3D&md5=d315d9f62a2e03c6267ea55284674be5CAS |
Diffendorfer, J. E. (1998). Testing models of source–sink dynamics and balanced dispersal. Oikos 81, 417–433.
Donker, S. A., and Krebs, C. J. (2011). Habitat specific distribution and abundance of arctic ground squirrels (Urocitellus parryii plesius) in southwest Yukon. Canadian Journal of Zoology 89, 577–583.
Eriksson, O. (1996). Regional dynamics of plants: a review of evidence for remnant, source–sink and metapopulations. Oikos 77, 248–258.
| Regional dynamics of plants: a review of evidence for remnant, source–sink and metapopulations.Crossref | GoogleScholarGoogle Scholar |
Fairbanks, B., and Dobson, F. S. (2007). Mechanisms of the group-size effect on vigilance in Columbian ground squirrels: dilution versus detection. Animal Behaviour 73, 115–123.
| Mechanisms of the group-size effect on vigilance in Columbian ground squirrels: dilution versus detection.Crossref | GoogleScholarGoogle Scholar |
Franklin, A. B. (2001). Exploring ecological relationships in survival and estimating rates of population change using program MARK. In ‘Wildlife, Land and People: Priorities for the 21st Century. Proceedings of the Second International Wildlife Management Congress’. (Eds R. Field, R. J. Warren, H. Okarma and P. R. Sievert.) pp. 290–296. (The Wildlife Society: Bethesda, MD.)
Gillis, E. A. (2003). Breeding dispersal, male mating tactics and population dynamics of arctic ground squirrels. Ph.D. Thesis, University of British Columbia, Vancouver, BC, Canada.
Gillis, E. A., Hik, D. S., Boonstra, R., Karels, T. J., and Krebs, C. J. (2005). Being high is better: effects of elevation and habitat on arctic ground squirrel demography. Oikos 108, 231–240.
| Being high is better: effects of elevation and habitat on arctic ground squirrel demography.Crossref | GoogleScholarGoogle Scholar |
Green, J. E. (1977). Population regulation and annual cycles of activity and dispersal in the arctic ground squirrel. M.Sc. Thesis, University of British Columbia, Vancouver, BC, Canada.
Gundersen, G., Johannesen, E., Andreassen, H. P., and Ims, R. A. (2001). Source–sink dynamics: how sinks affect demography of sources. Ecology Letters 4, 14–21.
| Source–sink dynamics: how sinks affect demography of sources.Crossref | GoogleScholarGoogle Scholar |
Hanski, I. (1998). Metapopulation dynamics Nature 396, 41–49.
| Metapopulation dynamicsCrossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXntl2rurw%3D&md5=8adccc681cb2b00c9f59c454dfb06d49CAS |
Hik, D. S., McColl, C. J., and Boonstra, R. (2001). Why are arctic ground squirrels more stressed in the boreal forest than in alpine meadows? Ecoscience 8, 275–288.
Hubbs, A. H., and Boonstra, R. (1997). Population limitation in arctic ground squirrels: effects of food and predation. Journal of Animal Ecology 66, 527–541.
| Population limitation in arctic ground squirrels: effects of food and predation.Crossref | GoogleScholarGoogle Scholar |
Johnson, D. M. (2004). Source–sink dynamics in a temporally heterogeneous environment. Ecology 85, 2037–2045.
| Source–sink dynamics in a temporally heterogeneous environment.Crossref | GoogleScholarGoogle Scholar |
Kanda, L. L., Fuller, T. K., Sievert, P. R., and Kellogg, R. L. (2009). Seasonal source–sink dynamics at the edge of a species’ range. Ecology 90, 1574–1585.
| Seasonal source–sink dynamics at the edge of a species’ range.Crossref | GoogleScholarGoogle Scholar |
Karels, T. J., and Boonstra, R. (1999). The impact of predation on burrow use by arctic ground squirrels in the boreal forest. Proceedings of the Royal Society of London. Series B. Biological Sciences 266, 2117–2123.
| The impact of predation on burrow use by arctic ground squirrels in the boreal forest.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD3czlvVensw%3D%3D&md5=444adc6beac240c5c5f8025ec84ed99dCAS |
Karels, T. J., and Boonstra, R. (2000). Concurrent density dependence and independence in populations of arctic ground squirrels. Nature 408, 460–463.
| Concurrent density dependence and independence in populations of arctic ground squirrels.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXos1Srtr4%3D&md5=824fa0ddc23445f776747e9c9f7dcbe5CAS |
Karels, T. J., Byrom, A. E., Boonstra, R., and Krebs, C. J. (2000). The interactive effects of food and predators on reproduction and overwinter survival of arctic ground squirrels. Journal of Animal Ecology 69, 235–247.
| The interactive effects of food and predators on reproduction and overwinter survival of arctic ground squirrels.Crossref | GoogleScholarGoogle Scholar |
Kildaw, S. D. (1995). The effect of group size manipulations on the foraging behavior of black-tailed prairie dogs. Behavioral Ecology 6, 353–358.
| The effect of group size manipulations on the foraging behavior of black-tailed prairie dogs.Crossref | GoogleScholarGoogle Scholar |
Kristan, W. B. (2003). The role of habitat selection behavior in population dynamics: source–sink systems and ecological traps. Oikos 103, 457–468.
| The role of habitat selection behavior in population dynamics: source–sink systems and ecological traps.Crossref | GoogleScholarGoogle Scholar |
Krebs, C. J., Boutin, S., and Boonstra, R. (eds). (2001). ‘Ecosystem Dynamics of the Boreal Forest: the Kluane Project.’ (Oxford University Press: New York.)
Lacey, E. A. (1991). Reproductive and dispersal strategies of male arctic ground squirrels (Spermophilus parryii plesius). Ph. D. Thesis, University of Michigan, MI, USA.
Lacey, E. A., Wieczorek, J. R., and Tucker, P. K. (1997). Male mating behaviour and patterns of sperm precedence in Arctic ground squirrels. Animal Behaviour 53, 767–779.
Lampila, S., Wistbacka, R., Makela, A., and Orell, M. (2009). Survival and population growth rate of the threatened siberian flying squirrel (Pteromys volans) in a fragmented forest landscape. Ecoscience 16, 66–74.
| Survival and population growth rate of the threatened siberian flying squirrel (Pteromys volans) in a fragmented forest landscape.Crossref | GoogleScholarGoogle Scholar |
Leibold, M. A., Holyoak, M., Mouquet, N., Amarasekare, P., Chase, J. M., Hoopes, M. F., Holt, R. D., Shurin, J. B., Law, R., Tilman, D., Loreau, M., and Gonzalez, A. (2004). The metacommunity concept: a framework for multi-scale community ecology. Ecology Letters 7, 601–613.
| The metacommunity concept: a framework for multi-scale community ecology.Crossref | GoogleScholarGoogle Scholar |
Lima, S. L. (1995). Back to the basics of anti-predatory vigilance: the group-size effect. Animal Behaviour 49, 11–20.
| Back to the basics of anti-predatory vigilance: the group-size effect.Crossref | GoogleScholarGoogle Scholar |
Nadler, C. F., and Hoffman, R. S. (1977). Patterns of evolution and migration in the arctic ground squirrel (Spermophilus parryii). Canadian Journal of Zoology 55, 748–758.
| Patterns of evolution and migration in the arctic ground squirrel (Spermophilus parryii).Crossref | GoogleScholarGoogle Scholar |
Nappi, A., and Drapeau, P. (2009). Reproductive success of the black-backed woodpecker (Picoides arcticus) in burned boreal forests: are burns source habitats? Biological Conservation 142, 1381–1391.
| Reproductive success of the black-backed woodpecker (Picoides arcticus) in burned boreal forests: are burns source habitats?Crossref | GoogleScholarGoogle Scholar |
O’Keefe, K. I. M., Ramakrishnan, U. M. A., Van Tuinen, M., and Hadly, E. A. (2009). Source–sink dynamics structure a common montane mammal. Molecular Ecology 18, 4775–4789.
| Source–sink dynamics structure a common montane mammal.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXjslKqsw%3D%3D&md5=c17c39170ea24617b77751be91115107CAS |
Peery, M. Z., Becker, B. H., and Beissinger, S. R. (2006). Combining demographic and count-based approaches to identify source-sink dynamics of a threatened seabird. Ecological Applications 16, 1516–1528.
| Combining demographic and count-based approaches to identify source-sink dynamics of a threatened seabird.Crossref | GoogleScholarGoogle Scholar |
Perlut, N. G., Strong, A. M., Donovan, T. M., and Buckley, N. J. (2008). Grassland songbird survival and recruitment in agricultural landscapes: implications for source-sink demography. Ecology 89, 1941–1952.
| Grassland songbird survival and recruitment in agricultural landscapes: implications for source-sink demography.Crossref | GoogleScholarGoogle Scholar |
Pollock, K. H., Winterstein, S. R., Bunck, C. M., and Curtis, P. D. (1989). Survival analysis in telemetry studies: the staggered entry design. The Journal of Wildlife Management 53, 7–15.
| Survival analysis in telemetry studies: the staggered entry design.Crossref | GoogleScholarGoogle Scholar |
Pradel, R. (1996). Utilization of capture-mark-recapture for the study of recruitment and population growth rate. Biometrics 52, 703–709.
| Utilization of capture-mark-recapture for the study of recruitment and population growth rate.Crossref | GoogleScholarGoogle Scholar |
Pulliam, H. R. (1988). Sources, sinks, and population regulation. American Naturalist 132, 652.
| Sources, sinks, and population regulation.Crossref | GoogleScholarGoogle Scholar |
Pulliam, H. R. (2000). On the relationship between niche and distribution. Ecology Letters 3, 349–361.
| On the relationship between niche and distribution.Crossref | GoogleScholarGoogle Scholar |
Roberts, G. (1996). Why individual vigilance declines as group size increases. Animal Behaviour 51, 1077–1086.
| Why individual vigilance declines as group size increases.Crossref | GoogleScholarGoogle Scholar |
Schooley, R. L., and Branch, L. C. (2009). Enhancing the area-isolation paradigm: habitat heterogeneity and metapopulation dynamics of a rare wetland mammal. Ecological Applications 19, 1708–1722.
| Enhancing the area-isolation paradigm: habitat heterogeneity and metapopulation dynamics of a rare wetland mammal.Crossref | GoogleScholarGoogle Scholar |
Watkinson, A. R., and Sutherland, W. J. (1995). Sources, sinks and pseudo-sinks. Journal of Animal Ecology 64, 126–130.
| Sources, sinks and pseudo-sinks.Crossref | GoogleScholarGoogle Scholar |
White, G. C., and Burnham, K. P. (1999). Program MARK: survival estimation from populations of marked animals. Bird Study 46, 120–139.
| Program MARK: survival estimation from populations of marked animals.Crossref | GoogleScholarGoogle Scholar |
