title: Fine-scale local adaptation in an invasive freshwater fish has evolved in contemporary time.
abstract: Adaptive evolutionary change in only a few generations can increase the ability of non-native invasive species to spread, and yet adaptive divergence is rarely assessed in recently established populations. In this study, we experimentally test for evidence of fine-scale local adaptation in juvenile survival and growth among three populations of an invasive freshwater fish with reciprocal transplants and common-garden experiments. Despite intrinsic differences in habitat quality, in two of three populations we detected evidence of increased survival in 'home' versus 'away' environments with a Bayesian occupancy model fitted to mark-recapture data. We found support for the 'local' versus 'foreign' criterion of local adaptation as 14 of 15 pairwise comparisons of performance were consistent with local adaptation (p < 0.001). Patterns in growth were less clear, though we detected evidence of location- and population-level effects. Although the agents of divergent ecological selection are not known in this system, our results combine to indicate that adaptive divergence--reflected by higher relative survival of local individuals--can occur in a small number of generations and only a few kilometres apart on the landscape.
authors.affiliation: Ocean Sciences Centre, Memorial University of Newfoundland, St John's, Newfoundland, Canada. resolute@uw.edu
authors.forename: Peter A H
authors.initials: PA
authors.lastname: Westley
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Ward
authors.forename: Ian A
authors.initials: IA
authors.lastname: Fleming
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D000704:Analysis of Variance; D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D003433:Crosses, Genetic; D017753:Ecosystem; D005618:Fresh Water; D058865:Introduced Species; D009523:Newfoundland and Labrador; D016017:Odds Ratio; D012641:Selection, Genetic; D016019:Survival Analysis; D014337:Trout / Q000235:genetics / Q000254:growth & development*