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Living in the past: phylogeography and population histories of Indo-Pacific wrasses (genus Halichoeres) in shallow lagoons versus outer reef slopes.

Ludt WB, Bernal MA, Bowen BW, Rocha LA - PLoS ONE (2012)

Bottom Line: The outer reef species showed significantly less population structure, consistent with longer pelagic larval durations.Mismatch distributions and significant negative Fu's F values indicate Pleistocene population expansion for all species, and (contrary to expectations) shallower histories in the outer slope species.We conclude that lagoonal wrasses may persist through glacial habitat disruptions, but are restricted to refugia during lower sea level stands.

View Article: PubMed Central - PubMed

Affiliation: Department of Marine Science, University of Texas, Austin, Texas, United States of America. wbludt@gmail.com

ABSTRACT
Sea level fluctuations during glacial cycles affect the distribution of shallow marine biota, exposing the continental shelf on a global scale, and displacing coral reef habitat to steep slopes on oceanic islands. In these circumstances we expect that species inhabiting lagoons should show shallow genetic architecture relative to species inhabiting more stable outer reefs. Here we test this expectation on an ocean-basin scale with four wrasses (genus Halichoeres): H. claudia (N = 194, with ocean-wide distribution) and H. ornatissimus (N = 346, a Hawaiian endemic) inhabit seaward reef slopes, whereas H. trimaculatus (N = 239) and H. margaritaceus (N = 118) inhabit lagoons and shallow habitats throughout the Pacific. Two mitochondrial markers (cytochrome oxidase I and control region) were sequenced to resolve population structure and history of each species. Haplotype and nucleotide diversity were similar among all four species. The outer reef species showed significantly less population structure, consistent with longer pelagic larval durations. Mismatch distributions and significant negative Fu's F values indicate Pleistocene population expansion for all species, and (contrary to expectations) shallower histories in the outer slope species. We conclude that lagoonal wrasses may persist through glacial habitat disruptions, but are restricted to refugia during lower sea level stands. In contrast, outer reef slope species have homogeneous and well-connected populations through their entire ranges regardless of sea level fluctuations. These findings contradict the hypothesis that shallow species are less genetically diverse as a consequence of glacial cycles.

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Related in: MedlinePlus

Sampling locations per species.Map of the Indo-Pacific region where samples of all species were collected. 1) Cocos Keeling Island, 2) Christmas Island, 3) Palau, 4) Kwajalein, Marshall Islands, 5) Fiji, 6) Palmyra, 7) Kiribati, 8) Moorea, 9) Marquesas, 10) Hawaiian Archipelago. Colors in the pie charts indicate species sampled at each location.
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pone-0038042-g001: Sampling locations per species.Map of the Indo-Pacific region where samples of all species were collected. 1) Cocos Keeling Island, 2) Christmas Island, 3) Palau, 4) Kwajalein, Marshall Islands, 5) Fiji, 6) Palmyra, 7) Kiribati, 8) Moorea, 9) Marquesas, 10) Hawaiian Archipelago. Colors in the pie charts indicate species sampled at each location.

Mentions: We sampled Halichoeres claudia (n = 194, 5 locations), H. ornatissimus (n = 346, 13 locations), H. trimaculatus (n = 239, 7 locations), and H. margaritaceus (n = 118, 3 locations) from 21 locations in the Indian and Pacific Oceans (Fig. 1). All samples were collected using pole spears while SCUBA diving or snorkeling between 2006 and 2009. Fin clips or gill tissues were subsequently stored in either 95% ethanol or saturated salt (NaCL) solution with 20% DMSO [18]. DNA was later extracted using the “Hot-Shot” method described in Meeker et al. [19] and stored at 10°C before PCR amplification. All necessary permits were obtained for the described field studies. Permits were obtained from the following authorities: US Fish and Wildlife Service, Hawaii Department of Land and Natural Resources, Hawaii Papahānaumokuākea Marine National Monument, Palau Marine Resources Office, Marshall Islands Marine Resource Authority, Kiribati Ministry of Fishes and Marine Resources, Australia Department of Environment and Natural Resources, French Polynesia Fisheries Department, and the Fiji Ministry of Fisheries and Forests.


Living in the past: phylogeography and population histories of Indo-Pacific wrasses (genus Halichoeres) in shallow lagoons versus outer reef slopes.

Ludt WB, Bernal MA, Bowen BW, Rocha LA - PLoS ONE (2012)

Sampling locations per species.Map of the Indo-Pacific region where samples of all species were collected. 1) Cocos Keeling Island, 2) Christmas Island, 3) Palau, 4) Kwajalein, Marshall Islands, 5) Fiji, 6) Palmyra, 7) Kiribati, 8) Moorea, 9) Marquesas, 10) Hawaiian Archipelago. Colors in the pie charts indicate species sampled at each location.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368945&req=5

pone-0038042-g001: Sampling locations per species.Map of the Indo-Pacific region where samples of all species were collected. 1) Cocos Keeling Island, 2) Christmas Island, 3) Palau, 4) Kwajalein, Marshall Islands, 5) Fiji, 6) Palmyra, 7) Kiribati, 8) Moorea, 9) Marquesas, 10) Hawaiian Archipelago. Colors in the pie charts indicate species sampled at each location.
Mentions: We sampled Halichoeres claudia (n = 194, 5 locations), H. ornatissimus (n = 346, 13 locations), H. trimaculatus (n = 239, 7 locations), and H. margaritaceus (n = 118, 3 locations) from 21 locations in the Indian and Pacific Oceans (Fig. 1). All samples were collected using pole spears while SCUBA diving or snorkeling between 2006 and 2009. Fin clips or gill tissues were subsequently stored in either 95% ethanol or saturated salt (NaCL) solution with 20% DMSO [18]. DNA was later extracted using the “Hot-Shot” method described in Meeker et al. [19] and stored at 10°C before PCR amplification. All necessary permits were obtained for the described field studies. Permits were obtained from the following authorities: US Fish and Wildlife Service, Hawaii Department of Land and Natural Resources, Hawaii Papahānaumokuākea Marine National Monument, Palau Marine Resources Office, Marshall Islands Marine Resource Authority, Kiribati Ministry of Fishes and Marine Resources, Australia Department of Environment and Natural Resources, French Polynesia Fisheries Department, and the Fiji Ministry of Fisheries and Forests.

Bottom Line: The outer reef species showed significantly less population structure, consistent with longer pelagic larval durations.Mismatch distributions and significant negative Fu's F values indicate Pleistocene population expansion for all species, and (contrary to expectations) shallower histories in the outer slope species.We conclude that lagoonal wrasses may persist through glacial habitat disruptions, but are restricted to refugia during lower sea level stands.

View Article: PubMed Central - PubMed

Affiliation: Department of Marine Science, University of Texas, Austin, Texas, United States of America. wbludt@gmail.com

ABSTRACT
Sea level fluctuations during glacial cycles affect the distribution of shallow marine biota, exposing the continental shelf on a global scale, and displacing coral reef habitat to steep slopes on oceanic islands. In these circumstances we expect that species inhabiting lagoons should show shallow genetic architecture relative to species inhabiting more stable outer reefs. Here we test this expectation on an ocean-basin scale with four wrasses (genus Halichoeres): H. claudia (N = 194, with ocean-wide distribution) and H. ornatissimus (N = 346, a Hawaiian endemic) inhabit seaward reef slopes, whereas H. trimaculatus (N = 239) and H. margaritaceus (N = 118) inhabit lagoons and shallow habitats throughout the Pacific. Two mitochondrial markers (cytochrome oxidase I and control region) were sequenced to resolve population structure and history of each species. Haplotype and nucleotide diversity were similar among all four species. The outer reef species showed significantly less population structure, consistent with longer pelagic larval durations. Mismatch distributions and significant negative Fu's F values indicate Pleistocene population expansion for all species, and (contrary to expectations) shallower histories in the outer slope species. We conclude that lagoonal wrasses may persist through glacial habitat disruptions, but are restricted to refugia during lower sea level stands. In contrast, outer reef slope species have homogeneous and well-connected populations through their entire ranges regardless of sea level fluctuations. These findings contradict the hypothesis that shallow species are less genetically diverse as a consequence of glacial cycles.

Show MeSH
Related in: MedlinePlus