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dc.contributorVirginia Tech
dc.contributor.authorCooper, C. B.
dc.contributor.authorDaniels, S. J.
dc.contributor.authorWalters, J. R.
dc.date.accessioned2014-03-27T13:05:59Z
dc.date.available2014-03-27T13:05:59Z
dc.date.issued2008-12
dc.identifier.citationCaren B. Cooper, Susan J. Daniels, and Jeffrey R. Walters 2008. CAN WE IMPROVE ESTIMATES OF JUVENILE DISPERSAL DISTANCE AND SURVIVAL. Ecology 89:3349-3361. http://dx.doi.org/10.1890/08-0315.1
dc.identifier.issn0012-9658
dc.identifier.urihttp://hdl.handle.net/10919/46816
dc.description.abstractEstimates of distributions of natal dispersal distances and juvenile recruitment rates in open populations are strongly influenced by the extent and shape of the areas sampled. Techniques to improve biased dispersal and survival estimates include area-ratio methods based on weighting observations by sampling effort, the extent and shape of the area sampled, and the amount and distribution of preferred habitat surrounding the area sampled. We partitioned territories within the boundaries of a large, almost geographically closed, population of individually marked Red-cockaded Woodpeckers (Picoides borealis) and estimated dispersal and survival parameters from hypothetical smaller study areas (sampling areas) of varying sizes and shapes in order to examine whether an area-ratio method provides accurate or improved estimates of juvenile dispersal distance and survival. Non-aggregated sampling areas resulted in the detection of fewer dispersal events, but because of their large spatial extent, produced unbiased dispersal estimates. The use of aggregated sampling areas (circular or linear) resulted in the detection of higher numbers of dispersal events, but produced biased dispersal estimates that were generally improved by the area-ratio method. Area-ratio corrections usually provided better estimates of median dispersal distance than uncorrected estimates. Survival to breeding was usually underestimated and often not improved by the area-ratio method, regardless of extent and shape of the sampling area. Estimates of juvenile survival to breeding were improved by assuming that rates of emigration were equivalent to immigration, and correcting survival estimates accordingly. Small, local studies should use an area-ratio method to improve their estimates of median dispersal distance. Because the correction method estimates relative, but not absolute, numbers of individuals dispersing across distance categories, the area-ratio method should not be used for estimating survival. Non-aggregated sampling areas may be an effective design to increase spatial extent (and thus decrease bias) without proportionately increasing the amount of habitat sampled.
dc.description.sponsorshipNSF BSR-8307090, BSR-8717683
dc.description.sponsorshipU. S. Department of Defense, Department of the Army, Fort Bragg
dc.description.sponsorshipU. S. Fish and Wildlife Service
dc.description.sponsorshipNorth Carolina Wildlife Resources Commission
dc.description.sponsorshipSandhills Ecological Institute
dc.language.isoen_US
dc.publisherEcological Society of America
dc.subjectarea-ratio correction
dc.subjectband-resight
dc.subjectpicoides borealis
dc.subjectred-cockaded
dc.subjectwoodpecker
dc.subjectstudy area design
dc.subjectred-cockaded woodpecker
dc.subjectpollocks robust design
dc.subjectnatal dispersal
dc.subjectpopulation-dynamics
dc.subjecthabitat selection
dc.subjectseed dispersal
dc.subjectrecovery data
dc.subjectspotted owl
dc.subjectparus-major
dc.subjectgene flow
dc.titleCan we improve estimates of juvenile dispersal distance and survival?
dc.typeArticle - Refereed
dc.identifier.urlhttp://www.esajournals.org/doi/pdf/10.1890/08-0315.1
dc.date.accessed2014-03-11
dc.title.serialEcology
dc.identifier.doihttps://doi.org/10.1890/08-0315.1


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