title: Keeping things local: SubpopulationNbandNein a stream network with partial barriers to fish migration.
abstract: For organisms with overlapping generations that occur in metapopulations, uncertainty remains regarding the spatiotemporal scale of inference of estimates of the effective number of breeders (N^b) and whether these estimates can be used to predict generationalNe. We conducted a series of tests of the spatiotemporal scale of inference of estimates ofNbin nine consecutive cohorts within a long-term study of brook trout (Salvelinus fontinalis). We also tested a recently developed approach to estimate generationalNefrom N^b and compared this to an alternative approach for estimating N^e that also accounts for age structure. Multiple lines of evidence were consistent with N^b corresponding to the local (subpopulation) spatial scale and the cohort-specific temporal scale. We found that at least four consecutive cohort-specific estimates of N^b were necessary to obtain reliable estimates of harmonic mean N^b for a subpopulation. Generational N^e derived from cohort-specific N^b was within 7%-50% of an alternative approach to obtain N^e, suggesting some population specificity for concordance between approaches. Our results regarding the spatiotemporal scale of inference forNbshould apply broadly to many taxa that exhibit overlapping generations and metapopulation structure and point to promising avenues for using cohort-specific N^b for local-scale genetic monitoring.
authors.affiliation: Wildlife Biology Program Department of Ecosystem and Conservation Sciences College of Forestry and Conservation University of Montana Missoula MT USA.
authors.forename: Andrew R
authors.identifier: 0000-0001-8245-6236
authors.initials: AR
authors.lastname: Whiteley
authors.affiliation: Department of Environmental Conservation University of Massachusetts Amherst Amherst MA USA; U.S. Forest Service Northern Research Station University of Massachusetts Amherst MA USA.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Coombs
authors.affiliation: U.S. Geological Survey Leetown Science Center S.O. Conte Anadromous Fish Research Center Turners Falls MA USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: O'Donnell
authors.affiliation: U.S. Forest Service Northern Research Station University of Massachusetts Amherst MA USA.
authors.forename: Keith H
authors.initials: KH
authors.lastname: Nislow
authors.affiliation: U.S. Geological Survey Leetown Science Center S.O. Conte Anadromous Fish Research Center Turners Falls MA USA.
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Letcher
keywords: brook trout; effective number of breeders; effective population size; linkage disequilibrium; metapopulation; salmonid; stream fishes; temporal estimator