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Population structure among octocoral adults and recruits identifies scale dependent patterns of population isolation in The Bahamas.

Lasker HR, Porto-Hannes I - PeerJ (2015)

Bottom Line: Analysis of recruits from 4 sites on the LBB from up to 6 years did not detect differences between years nor differences with adult populations.The result suggests that neither selection on recruits nor inter-annual variation in dispersal affected adult population structure.Recognition of these complex patterns is important in developing management plans for A. elisabethae and in understanding the effects of disturbance to adult populations of A. elisabethae and similar species with limited dispersal.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Geology, University at Buffalo , Buffalo, NY , USA ; Graduate Program in Evolution, Ecology and Behavior, University at Buffalo , Buffalo, NY , USA.

ABSTRACT
Patterns of dispersal and connectivity of the Caribbean gorgonian Antillogorgia elisabethae in The Bahamas were assessed in both adults and recently settled recruits from 13 sites using microsatellite loci. Adult populations along the Little Bahama Bank (LBB) exhibited a clear pattern of isolation by distance (IBD) which described 86% of the variance in pairwise genetic distances. Estimates of dispersal based on the IBD model suggested dispersal distances along the LBB on the order of 100 m. Increasing the spatial scale to include sites separated by open ocean generated an apparent IBD signal but the relationship had a greater slope and explained less of the variance. This relationship with distance reflected both stepping stone based IBD and regional differentiation probably created by ocean currents and barriers to dispersal that are correlated with geographic distance. Analysis of recruits from 4 sites on the LBB from up to 6 years did not detect differences between years nor differences with adult populations. The result suggests that neither selection on recruits nor inter-annual variation in dispersal affected adult population structure. Assignment tests of recruits indicated the most likely sources of the recruits were the local or adjacent populations. Most of the patterning in population structure in the northern Bahamas can be explained by geographic distance and oceanographic connectivity. Recognition of these complex patterns is important in developing management plans for A. elisabethae and in understanding the effects of disturbance to adult populations of A. elisabethae and similar species with limited dispersal.

No MeSH data available.


Related in: MedlinePlus

Geneland analysis of A. elisabethae populations in The Bahamas.Spatial distribution of estimated populations by Geneland (K = 8). Continuous grey lines show the estimated population partitions, and dashed lines depict the edge of the Little Bahama and Great Bahama Banks. Abbreviations as in Table 1. Map source: World_Light_Gray_Base from Esri, HERE, DeLorme, MapmyIndia, © OpenStreetMap contributors, and the GIS user community. Map created in ArcGIS v. 10.1
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fig-4: Geneland analysis of A. elisabethae populations in The Bahamas.Spatial distribution of estimated populations by Geneland (K = 8). Continuous grey lines show the estimated population partitions, and dashed lines depict the edge of the Little Bahama and Great Bahama Banks. Abbreviations as in Table 1. Map source: World_Light_Gray_Base from Esri, HERE, DeLorme, MapmyIndia, © OpenStreetMap contributors, and the GIS user community. Map created in ArcGIS v. 10.1

Mentions: Geneland incorporates the geographic location of the samples in its analysis, and the analysis partitioned the data into K = 8 clusters (Fig. 4). The grouping within the LBB sites and EGG changed with different λ values. When λ = 2, all LBB sites except WC formed one group. At λ = 5–100, WC formed a cluster, BS and SC another cluster and the rest of the LBB populations along with EGG formed a third cluster. At λ = 100, the most likely number of cluster was 10, however, two of these clusters were “unsampled” populations. The other 8 clusters were the same as described above. Although the Geneland analysis partitioned the sites into a greater number of populations, the results are concordant with the patterns seen in the Structure plots (Fig. 3). In both analyses there is a core of sites on the LBB. In the Structure analysis, sites on the LBB differed from adjacent sites by relatively small differences in the levels of admixture, while in some Geneland analyses those were further divided into the sites near Great Abaco (CHR, CHSL, GP, MI and sometimes EGG) and those closer to Grand Bahama (SC, BS). WC and TR which had different patterns of admixture in the Structure analysis were also distinct populations in the Geneland analysis.


Population structure among octocoral adults and recruits identifies scale dependent patterns of population isolation in The Bahamas.

Lasker HR, Porto-Hannes I - PeerJ (2015)

Geneland analysis of A. elisabethae populations in The Bahamas.Spatial distribution of estimated populations by Geneland (K = 8). Continuous grey lines show the estimated population partitions, and dashed lines depict the edge of the Little Bahama and Great Bahama Banks. Abbreviations as in Table 1. Map source: World_Light_Gray_Base from Esri, HERE, DeLorme, MapmyIndia, © OpenStreetMap contributors, and the GIS user community. Map created in ArcGIS v. 10.1
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493681&req=5

fig-4: Geneland analysis of A. elisabethae populations in The Bahamas.Spatial distribution of estimated populations by Geneland (K = 8). Continuous grey lines show the estimated population partitions, and dashed lines depict the edge of the Little Bahama and Great Bahama Banks. Abbreviations as in Table 1. Map source: World_Light_Gray_Base from Esri, HERE, DeLorme, MapmyIndia, © OpenStreetMap contributors, and the GIS user community. Map created in ArcGIS v. 10.1
Mentions: Geneland incorporates the geographic location of the samples in its analysis, and the analysis partitioned the data into K = 8 clusters (Fig. 4). The grouping within the LBB sites and EGG changed with different λ values. When λ = 2, all LBB sites except WC formed one group. At λ = 5–100, WC formed a cluster, BS and SC another cluster and the rest of the LBB populations along with EGG formed a third cluster. At λ = 100, the most likely number of cluster was 10, however, two of these clusters were “unsampled” populations. The other 8 clusters were the same as described above. Although the Geneland analysis partitioned the sites into a greater number of populations, the results are concordant with the patterns seen in the Structure plots (Fig. 3). In both analyses there is a core of sites on the LBB. In the Structure analysis, sites on the LBB differed from adjacent sites by relatively small differences in the levels of admixture, while in some Geneland analyses those were further divided into the sites near Great Abaco (CHR, CHSL, GP, MI and sometimes EGG) and those closer to Grand Bahama (SC, BS). WC and TR which had different patterns of admixture in the Structure analysis were also distinct populations in the Geneland analysis.

Bottom Line: Analysis of recruits from 4 sites on the LBB from up to 6 years did not detect differences between years nor differences with adult populations.The result suggests that neither selection on recruits nor inter-annual variation in dispersal affected adult population structure.Recognition of these complex patterns is important in developing management plans for A. elisabethae and in understanding the effects of disturbance to adult populations of A. elisabethae and similar species with limited dispersal.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Geology, University at Buffalo , Buffalo, NY , USA ; Graduate Program in Evolution, Ecology and Behavior, University at Buffalo , Buffalo, NY , USA.

ABSTRACT
Patterns of dispersal and connectivity of the Caribbean gorgonian Antillogorgia elisabethae in The Bahamas were assessed in both adults and recently settled recruits from 13 sites using microsatellite loci. Adult populations along the Little Bahama Bank (LBB) exhibited a clear pattern of isolation by distance (IBD) which described 86% of the variance in pairwise genetic distances. Estimates of dispersal based on the IBD model suggested dispersal distances along the LBB on the order of 100 m. Increasing the spatial scale to include sites separated by open ocean generated an apparent IBD signal but the relationship had a greater slope and explained less of the variance. This relationship with distance reflected both stepping stone based IBD and regional differentiation probably created by ocean currents and barriers to dispersal that are correlated with geographic distance. Analysis of recruits from 4 sites on the LBB from up to 6 years did not detect differences between years nor differences with adult populations. The result suggests that neither selection on recruits nor inter-annual variation in dispersal affected adult population structure. Assignment tests of recruits indicated the most likely sources of the recruits were the local or adjacent populations. Most of the patterning in population structure in the northern Bahamas can be explained by geographic distance and oceanographic connectivity. Recognition of these complex patterns is important in developing management plans for A. elisabethae and in understanding the effects of disturbance to adult populations of A. elisabethae and similar species with limited dispersal.

No MeSH data available.


Related in: MedlinePlus