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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

Structure analysis of A. elisabethae populations in The Bahamas.Results of Structure analysis. (A) plot of Evanno’s delta K as a function of the number of putative populations for simulations including all 13 sites and 10 loci and (B), inferred population structure. (C) plot of Evanno’s delta K as a function of the number of putative populations for simulations excluding the Exuma Sound and San Salvador populations and D, inferred population structure. Site abbreviations as in Table 1.
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fig-3: Structure analysis of A. elisabethae populations in The Bahamas.Results of Structure analysis. (A) plot of Evanno’s delta K as a function of the number of putative populations for simulations including all 13 sites and 10 loci and (B), inferred population structure. (C) plot of Evanno’s delta K as a function of the number of putative populations for simulations excluding the Exuma Sound and San Salvador populations and D, inferred population structure. Site abbreviations as in Table 1.

Mentions: The Structure and Geneland analyses of the populations clearly characterized the complex nature of population structure of A. elisabethae in The Bahamas. An initial Structure analysis, which included all 13 sites exhibited a best fit model of K = 2 (data not shown) in which colonies from Exuma Sound (HC) and San Salvador (PR) generally belonged to one population and those from the other sites to a second population. Subsequent analysis without the Exuma Sound (HC) and San Salvador (PR) collections generated highly variable results. LnP[k] values from the Structure analyses did not monotonically increase with increasing K, and there were high levels of variance at K values >3, both of which suggested the simulations were not converging. Increased steps (200,000 burn in and 106 MCMC replications) had no appreciable effect on the results. Repeating the analysis using all 10 loci; i.e., including those in which alleles were present, also indicated K = 2 when all 13 sites were included (Figs. 3A and 3B). The individuals from San Salvador (PR) belonged to a distinct population with those from Exuma Sound (HC) exhibiting admixture between the San Salvador (PR) population and a second population, which was represented by the colonies from the remaining sites. That analysis suggested K = 3 among the 11 sites (Figs. 3C and 3D).


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

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

Structure analysis of A. elisabethae populations in The Bahamas.Results of Structure analysis. (A) plot of Evanno’s delta K as a function of the number of putative populations for simulations including all 13 sites and 10 loci and (B), inferred population structure. (C) plot of Evanno’s delta K as a function of the number of putative populations for simulations excluding the Exuma Sound and San Salvador populations and D, inferred population structure. Site abbreviations as in Table 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig-3: Structure analysis of A. elisabethae populations in The Bahamas.Results of Structure analysis. (A) plot of Evanno’s delta K as a function of the number of putative populations for simulations including all 13 sites and 10 loci and (B), inferred population structure. (C) plot of Evanno’s delta K as a function of the number of putative populations for simulations excluding the Exuma Sound and San Salvador populations and D, inferred population structure. Site abbreviations as in Table 1.
Mentions: The Structure and Geneland analyses of the populations clearly characterized the complex nature of population structure of A. elisabethae in The Bahamas. An initial Structure analysis, which included all 13 sites exhibited a best fit model of K = 2 (data not shown) in which colonies from Exuma Sound (HC) and San Salvador (PR) generally belonged to one population and those from the other sites to a second population. Subsequent analysis without the Exuma Sound (HC) and San Salvador (PR) collections generated highly variable results. LnP[k] values from the Structure analyses did not monotonically increase with increasing K, and there were high levels of variance at K values >3, both of which suggested the simulations were not converging. Increased steps (200,000 burn in and 106 MCMC replications) had no appreciable effect on the results. Repeating the analysis using all 10 loci; i.e., including those in which alleles were present, also indicated K = 2 when all 13 sites were included (Figs. 3A and 3B). The individuals from San Salvador (PR) belonged to a distinct population with those from Exuma Sound (HC) exhibiting admixture between the San Salvador (PR) population and a second population, which was represented by the colonies from the remaining sites. That analysis suggested K = 3 among the 11 sites (Figs. 3C and 3D).

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