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Seed Mast Induced Population Synchrony in the White-footed Mouse Peromyscus leucopus

Seed Mast Induced Population Synchrony in the White-footed Mouse Peromyscus leucopus. Pei-Jen Shaner March 2005. Population Synchrony. Definition: Spatial covariation in population density fluctuations Measure: Cross-correlation coefficient (Bjørnstad et al. 1999).

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Seed Mast Induced Population Synchrony in the White-footed Mouse Peromyscus leucopus

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  1. Seed Mast Induced Population Synchrony in the White-footed Mouse Peromyscus leucopus Pei-Jen ShanerMarch 2005

  2. Population Synchrony Definition: Spatial covariation in population density fluctuations Measure: Cross-correlation coefficient (Bjørnstad et al. 1999) Eample: Soay sheep synchrony by Moran effect (Grenfell et al. 1998)

  3. Number of mice per 100 trappings Acorns per hectare (in thousands) (Elias et al. 2004) Seed Mast and the Deer Mouse (Peromyscus spp.) -Does seed mast induce population synchrony in the deer mouse? -What demographic processes drive the synchrony?

  4. Model I: direct demographic effects in situ recruitment adult survival juvenile survival reproduction recruitment population growth seed masting adult movement recruitment adult survival juvenile survival in situ recruitment reproduction

  5. Model II: indirect dispersal effects in situ recruitment adult survival juvenile survival reproduction recruitment population growth seed masting juvenile dispersal recruitment adult survival juvenile survival in situ recruitment reproduction

  6. Methods I: Mark-recapture and Demography Three annual cycles Population density(MNA) Survivorship(MARK) Reproduction: percent breeding females Recruitment: number juveniles per adult female

  7. Demographic variables estimated in situ recruitment in situ recruitment adult survival juvenile survival juvenile survival reproduction recruitment population growth adult movement juvenile dispersal recruitment adult survival juvenile survival juvenile survival in situ recruitment in situ recruitment reproduction seed masting

  8. Methods II: Isotopic Tracing of Adults and Juveniles September-October 2003 with a total of 200 pounds of seeds / grid Mixing equation: Δ xE (‰) = fb x (xEb) + (fm) x (xEm), where (fb + fm) = 1

  9. Habitat-specific Patterns in Population Synchrony Forest Field Cross-correlation coefficient 2001-02 2002-03 2003-04 2001-02 2002-03 2003-04

  10. Annual Survival *

  11. Adult Female Reproduction * *

  12. Juvenile Recruitment *

  13. * Adult Movement vs. Juvenile Dispersal

  14. in situ recruitment juvenile survival adult movement juvenile dispersal juvenile survival in situ recruitment Summary: direct versus indirect demographic effects adult survival reproduction recruitment population growth seed masting recruitment adult survival reproduction

  15. Conclusions Habitat-specific synchrony - effects of landscape fragmentation on population synchrony Seed mast induces synchrony mainly through juvenile dispersal - meta-population dynamics - genetic flow between populations Seed mast and spatial dynamics of consumer populations - landscape compositions and demographic processes are important

  16. Acknowledgement Bowers, Michael Carr, Dave Morris, Clay Sparding, Kimberly Kraus, Johanna Low, Candace Pedersen, Amy Funding: National Science Foundation Blandy Experimental Farm, VA

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