title: Archipelagos of the Anthropocene: rapid and extensive differentiation of native terrestrial vertebrates in a single metropolis.
abstract: Some of the best evidence for rapid evolutionary change comes from studies of archipelagos and oceanic islands. City parks are analogous systems as they create geographically isolated green spaces that differ in size, structure and complexity. Very little, however, is known about whether city parks within a single urban centre drive selection and result in the diversification of native species. Here, we provide evidence for the rapid genetic and morphological differentiation of a native lizard (Intellagama lesueurii) at four geographically close yet unconnected parks within one city. Year of establishment of each city park varied from 1855 (oldest) to 2001 (youngest) equating to a generation time range of 32 to three generations. Genetic divergence among city park populations was large despite the small pairwise geographic distances (<5 km) and found to be two to three times higher for microsatellites and three to 33 times higher for mtDNA relative to nonurban populations. Patterns of morphological differentiation were also found to be most extensive among the four city park populations. In contrast to nonurban populations, city park populations showed significant differentiation in relative body size, relative head and limb morphology and relative forelimb and hindlimb length. Crucially, we show that these patterns of differentiation are unlikely to have been caused by founder events and/or drift alone. Our results suggest that city park 'archipelagos' could represent theatres for rapid evolution that may, in time, favour adaptive diversification.
authors.affiliation: School of Science and Engineering, University of the Sunshine Coast, Maroochydore DC, Qld, 4556, Australia.
authors.forename: Bethan L
authors.initials: BL
authors.lastname: Littleford-Colquhoun
authors.affiliation: School of Science and Engineering, University of the Sunshine Coast, Maroochydore DC, Qld, 4556, Australia.
authors.forename: Christofer
authors.initials: C
authors.lastname: Clemente
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Whiting
authors.affiliation: School of Biological Sciences, University of Queensland, St. Lucia, Qld, 4072, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ortiz-Barrientos
authors.affiliation: School of Science and Engineering, University of the Sunshine Coast, Maroochydore DC, Qld, 4556, Australia.
authors.forename: Celine H
authors.identifier: http://orcid.org/0000-0002-9671-2138
authors.initials: CH
authors.lastname: Frère
mesh_terms: D000818:Animals; D002947:Cities; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D040961:Genetic Drift; D014644:Genetic Variation; D005828:Genetics, Population; D008116:Lizards / Q000033:anatomy & histology* / Q000235:genetics*; D018895:Microsatellite Repeats; D011793:Queensland
chemical_list: D004272:DNA, Mitochondrial
keywords: genetics; local adaptation; morphology; reptiles; urbanization