title: Gene flow from an adaptively divergent source causes rescue through genetic and demographic factors in two wild populations of Trinidadian guppies.
abstract: Genetic rescue, an increase in population growth owing to the infusion of new alleles, can aid the persistence of small populations. Its use as a management tool is limited by a lack of empirical data geared toward predicting effects of gene flow on local adaptation and demography. Experimental translocations provide an ideal opportunity to monitor the demographic consequences of gene flow. In this study we take advantage of two experimental introductions of Trinidadian guppies to test the effects of gene flow on downstream native populations. We individually marked guppies from the native populations to monitor population dynamics for 3 months before and 26 months after gene flow. We genotyped all individuals caught during the first 17 months at microsatellite loci to classify individuals by their genetic ancestry: native, immigrant, F1 hybrid, F2 hybrid, or backcross. Our study documents a combination of demographic and genetic rescue over multiple generations under fully natural conditions. Within both recipient populations, we found substantial and long-term increases in population size that could be attributed to high survival and recruitment caused by immigration and gene flow from the introduction sites. Our results suggest that low levels of gene flow, even from a divergent ecotype, can provide a substantial demographic boost to small populations, which may allow them to withstand environmental stochasticity.
authors.affiliation: Kellogg Biological Station Department of Integrative Biology Michigan State University Hickory Corners MI USA; Department of Biology Colorado State University Fort Collins CO USA.
authors.forename: Sarah W
authors.initials: SW
authors.lastname: Fitzpatrick
authors.affiliation: Department of Biology Colorado State University Fort Collins CO USA.
authors.forename: Jill C
authors.initials: JC
authors.lastname: Gerberich
authors.affiliation: Department of Biology Colorado State University Fort Collins CO USA; Graduate Degree Program in Ecology Colorado State University Fort Collins CO USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Angeloni
authors.affiliation: Department of Fish, Wildlife, and Conservation Biology Colorado State University Fort Collins CO USA.
authors.forename: Larissa L
authors.initials: LL
authors.lastname: Bailey
authors.affiliation: Department of Biology Colorado State University Fort Collins CO USA; Graduate Degree Program in Ecology Colorado State University Fort Collins CO USA.
authors.forename: Emily D
authors.initials: ED
authors.lastname: Broder
authors.affiliation: Lehrstuhl für Zoologie und Evolutionsbiologie Department of Biology University of Konstanz Konstanz Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Torres-Dowdall
authors.affiliation: Department of Biology Colorado State University Fort Collins CO USA.
authors.forename: Corey A
authors.initials: CA
authors.lastname: Handelsman
authors.affiliation: CNRS UMR 7618 Institute of Ecology and Environmental Sciences of Paris (iEES) Université Pierre et Marie Curie Paris France; Department of Biological and Environmental Sciences Center of Excellence in Biological Interactions University of Jyväskylä Jyväskylä Finland.
authors.forename: Andrés
authors.initials: A
authors.lastname: López-Sepulcre
authors.affiliation: Department of Biology University of California Riverside CA USA.
authors.forename: David N
authors.initials: DN
authors.lastname: Reznick
authors.affiliation: Department of Biology Colorado State University Fort Collins CO USA; Graduate Degree Program in Ecology Colorado State University Fort Collins CO USA.
authors.forename: Cameron K
authors.initials: CK
authors.lastname: Ghalambor
authors.affiliation: Department of Biology Colorado State University Fort Collins CO USA; Graduate Degree Program in Ecology Colorado State University Fort Collins CO USA.
authors.forename: W
authors.initials: W
authors.lastname: Chris Funk
keywords: Poecilia reticulata; capture‐mark‐recapture; demographic rescue; fitness; gene flow; genetic rescue; hybridization; population growth