BACKGROUND AND AIMS: Seagrasses are important facilitator species in shallow, soft-bottom marine environments worldwide and, in many places, are threatened by coastal development and eutrophication. One narrow-leaved species (Zostera marina) and one wide-leaved species, variously designated as Z. marina, Z. pacifica or Z. asiatica, are found off the California Channel Islands and adjacent California-Mexico coast. The aim of the present study was to confirm species identification genetically and to link patterns of genetic diversity, connectivity and hybridization among and within the populations with historical sea levels (Ice Age) or the contemporary environment. METHODS: Samples (n = 11-100) were collected from 28 sites off five California Channel Islands and six sites off the adjacent coast of southern California and Baja California, Mexico. DNA polymorphisms of the rDNA-ITS (internal transcribed spacer) cistron (nuclear), the matK intron (chloroplast) and nine microsatellite loci (nuclear) were examined in a population genetic and phylogeographic context. KEY RESULTS: All wide-leaved individuals were Z. pacifica, whereas narrow-leaved forms were Z. marina. Microsatellite genotypes were consistent with hybridization between the two species in three populations. The present distribution of Z. pacifica follows a glacial age land mass rather than present oceanographic regimes, but no link was observed between the present distribution of Z. marina and past or present environments. Island populations of Z. marina often were clonal and characterized by low genotypic diversity compared with populations along the Baja California coast. The high level of clonal connectivity around Santa Catalina Island indicated the importance of dispersal and subsequent re-establishment of vegetative fragments. CONCLUSIONS: The pristine environmental conditions of offshore islands do not guarantee maximum genetic diversity. Future restoration and transplantation efforts of seagrasses must recognize cryptic species and consider the degree of both genetic and genotypic variation in candidate donor populations.
BACKGROUND AND AIMS: Seagrasses are important facilitator species in shallow, soft-bottom marine environments worldwide and, in many places, are threatened by coastal development and eutrophication. One narrow-leaved species (Zostera marina) and one wide-leaved species, variously designated as Z. marina, Z. pacifica or Z. asiatica, are found off the California Channel Islands and adjacent California-Mexico coast. The aim of the present study was to confirm species identification genetically and to link patterns of genetic diversity, connectivity and hybridization among and within the populations with historical sea levels (Ice Age) or the contemporary environment. METHODS: Samples (n = 11-100) were collected from 28 sites off five California Channel Islands and six sites off the adjacent coast of southern California and Baja California, Mexico. DNA polymorphisms of the rDNA-ITS (internal transcribed spacer) cistron (nuclear), the matK intron (chloroplast) and nine microsatellite loci (nuclear) were examined in a population genetic and phylogeographic context. KEY RESULTS: All wide-leaved individuals were Z. pacifica, whereas narrow-leaved forms were Z. marina. Microsatellite genotypes were consistent with hybridization between the two species in three populations. The present distribution of Z. pacifica follows a glacial age land mass rather than present oceanographic regimes, but no link was observed between the present distribution of Z. marina and past or present environments. Island populations of Z. marina often were clonal and characterized by low genotypic diversity compared with populations along the Baja California coast. The high level of clonal connectivity around Santa Catalina Island indicated the importance of dispersal and subsequent re-establishment of vegetative fragments. CONCLUSIONS: The pristine environmental conditions of offshore islands do not guarantee maximum genetic diversity. Future restoration and transplantation efforts of seagrasses must recognize cryptic species and consider the degree of both genetic and genotypic variation in candidate donor populations.
Authors: T D Herbert; J D Schuffert; D Andreasen; L Heusser; M Lyle; A Mix; A C Ravelo; L D Stott; J C Herguera Journal: Science Date: 2001-07-06 Impact factor: 47.728
Authors: Raquel Muñiz-Salazar; Sandra L Talbot; George K Sage; David H Ward; Alejandro Cabello-Pasini Journal: Mol Ecol Date: 2005-03 Impact factor: 6.185
Authors: Jeanine L Olsen; Wytze T Stam; James A Coyer; Thorsten B H Reusch; Martin Billingham; Christoffer Boström; Elizabeth Calvert; Hartvig Christie; Stephen Granger; Richard la Lumière; Nataliya Milchakova; Marie-Pierre Oudot-Le Secq; Gabriele Procaccini; Bahram Sanjabi; Ester Serrao; Jan Veldsink; Stephen Widdicombe; Sandy Wyllie-Echeverria Journal: Mol Ecol Date: 2004-07 Impact factor: 6.185
Authors: Jane M Edgeloe; Anita A Severn-Ellis; Philipp E Bayer; Shaghayegh Mehravi; Martin F Breed; Siegfried L Krauss; Jacqueline Batley; Gary A Kendrick; Elizabeth A Sinclair Journal: Proc Biol Sci Date: 2022-06-01 Impact factor: 5.530
Authors: Andreas M Zipperle; James A Coyer; Karsten Reise; Eelo Gitz; Wytze T Stam; Jeanine L Olsen Journal: Mar Biol Date: 2009-07-05 Impact factor: 2.573
Authors: Sandra L Talbot; George K Sage; Jolene R Rearick; Meg C Fowler; Raquel Muñiz-Salazar; Bethany Baibak; Sandy Wyllie-Echeverria; Alejandro Cabello-Pasini; David H Ward Journal: PLoS One Date: 2016-04-22 Impact factor: 3.240