Abstract
Corridors are a popular tool for conservation of small populations. However, two purported benefits of corridors, increasing gene flow and providing a means for the recolonization of extinct patches of habitat (population rescue), may have unappreciated impacts on the likelihood that a new allele will become incorporated (fixed) within a population. Using a simulation model, I demonstrate that connecting a stable, isolated population with a population that requires periodic rescue (due to extinction via natural or anthropogenic disturbance) can affect fixation of alleles in the stable population, largely by changing the effective population size Ne of the two-patch complex. When disturbance is rare, connecting the two patches with corridors can increase fixation of beneficial alleles and increase loss of harmful alleles. However, the opposite occurs when rates of disturbance are high: corridors can promote fixation of harmful alleles and reduce fixation of beneficial alleles. Because the impact of corridors hinges upon disturbance frequency (i.e. rate of population rescue), population growth rate, movement rates, and habitat quality, different species are likely to have different responses to corridor-mediated fixation, even if the species reside within the same ecological community. By changing fixation, corridors could thus either promote adaptation or extinction.
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Acknowledgements
B. Danielson, M. Whitlock, F. Janzen, J. Nason, T. Kawecki, D. Coltman, E. Damschen, D. Adams, R. Dyer, N. Haddad, and the ELVIS labgroup at Iowa State University provided insightful discussion and comments on previous drafts of the manuscript. Financial support provided by the Ecology and Evolutionary Interdepartmental Graduate Program at ISU, the National Science Foundation, and a Science to Achieve Results Fellowship from the U.S. Environmental Protection Agency. Portions of this work were conducted while a Postdoctoral Associate at the National Center for Ecological Analysis and Synthesis, a Center funded by NSF (Grant #DEB-0072909), the University of California, and the Santa Barbara campus.
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Orrock, J.L. Conservation corridors affect the fixation of novel alleles. Conserv Genet 6, 623–630 (2005). https://doi.org/10.1007/s10592-005-9016-6
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DOI: https://doi.org/10.1007/s10592-005-9016-6