title: Colonization and demographic expansion of freshwater fauna across the Hawaiian archipelago.
abstract: It is widely accepted that insular terrestrial biodiversity progresses with island age because colonization and diversification proceed over time. Here, we assessed whether this principle extends to oceanic island streams. We examined rangewide mtDNA sequence variation in four stream-dwelling species across the Hawaiian archipelago to characterize the relationship between colonization and demographic expansion, and to determine whether either factor reflects island age. We found that colonization and demographic expansion are not related and that neither corresponds to island age. The snail Neritina granosa exhibited the oldest colonization time (~2.713 mya) and time since demographic expansion (~282 kya), likely reflecting a preference for lotic habitats most prevalent on young islands. Conversely, gobioid fishes (Awaous stamineus, Eleotris sandwicensis and Sicyopterus stimpsoni) colonized the archipelago only ~0.411-0.935 mya, suggesting ecological opportunities for colonization in this group were temporally constrained. These findings indicate that stream communities form across colonization windows, underscoring the importance of ecological opportunities in shaping island freshwater diversity.
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA. alda.fernando@gmail.com.|Tulane-Xavier Center for Bioenvironmental Research, Tulane University, New Orleans, LA, USA. alda.fernando@gmail.com.
authors.forename: F
authors.initials: F
authors.lastname: Alda
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.
authors.forename: R B
authors.initials: RB
authors.lastname: Gagne
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.|Department of Biological Science, California State University, Fullerton, Fullerton, CA, USA.
authors.forename: R P
authors.initials: RP
authors.lastname: Walter
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.|Department of Life Sciences, Texas A & M University - Corpus Christi, Corpus Christi, TX, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Hogan
authors.affiliation: Tulane-Xavier Center for Bioenvironmental Research, Tulane University, New Orleans, LA, USA.|Department of Biological Sciences, Clemson University, Clemson, SC, USA.
authors.forename: K N
authors.initials: KN
authors.lastname: Moody
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.
authors.forename: F
authors.initials: F
authors.lastname: Zink
authors.affiliation: Center for Limnology, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: P B
authors.initials: PB
authors.lastname: McIntyre
authors.affiliation: Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Gilliam
authors.affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.|Tulane-Xavier Center for Bioenvironmental Research, Tulane University, New Orleans, LA, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Blum
mesh_terms: D000818:Animals; D059001:Aquatic Organisms; D044822:Biodiversity; D005618:Fresh Water; D006254:Hawaii; D010473:Perciformes; D011157:Population Dynamics; D012908:Snails
keywords: Hawaiʻi; amphidromy; evolutionary history; goby; island biogeography; snail