title: Initial genetic diversity enhances population establishment and alters genetic structuring of a newly established Daphnia metapopulation.
abstract: When newly created habitats are initially colonized by genotypes with rapid population growth rates, later arriving colonists may be prevented from establishing. Although these priority effects have been documented in multiple systems, their duration may be influenced by the diversity of the founding population. We conducted a large-scale field manipulation to investigate how initial clonal diversity influences temporal and landscape patterns of genetic structure in a developing metapopulation. Six genotypes of obligately asexual Daphnia pulex were stocked alone (no clonal diversity) or in combination ('high' clonal diversity) into newly created experimental woodland ponds. We also measured the population growth rate of all clones in the laboratory when raised on higher-quality and lower-quality resources. Our predictions were that in the 3 years following stocking, clonally diverse populations would be more likely to persist than nonclonally diverse populations and exhibit evidence for persistent founder effects. We expected that faster growing clones would be found in more pools and comprise a greater proportion of individuals genotyped from the landscape. Genetic composition, both locally and regionally, changed significantly following stocking. Six of 27 populations exhibited evidence for persistent founder effects, and populations stocked with 'high' clonal diversity were more likely to exhibit these effects than nonclonally diverse populations. Performance in the laboratory was not predictive of clonal persistence or overall dominance in the field. Hence, we conclude that although laboratory estimates of fitness did not fully explain metapopulation genetic structure, initial clonal diversity did enhance D. pulex population establishment and persistence in this system.
authors.affiliation: Department of Animal Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign, 515 Morrill Hall, 505 S. Goodwin Ave, Urbana, IL, 61801, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Holmes
authors.affiliation: Centre d'Ecologie fonctionnelle et Evolutive, UMR 5175 CNRS - Université de Montpellier -EPHE, Campus CNRS, 1919 route de Mende, 34293, Montpellier Cedex 05, France.
authors.forename: Jelena H
authors.initials: JH
authors.lastname: Pantel
authors.affiliation: Department of Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY, 13210, USA.
authors.forename: Kimberly L
authors.initials: KL
authors.lastname: Schulz
authors.affiliation: Department of Animal Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign, 515 Morrill Hall, 505 S. Goodwin Ave, Urbana, IL, 61801, USA.
authors.forename: Carla E
authors.initials: CE
authors.lastname: Cáceres
mesh_terms: D000818:Animals; D003621:Daphnia / Q000235:genetics*; D017753:Ecosystem; D018703:Founder Effect; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D061005:Ponds
keywords: clonal structure; genetic differentiation; intraspecific diversity; persistent founder effects; population genetic structure