title: Conservation of eelgrass (Zostera marina) genetic diversity in a mesocosm-based restoration experiment.
abstract: Eelgrass (Zostera marina) forms the foundation of an important shallow coastal community in protected estuaries and bays. Widespread population declines have stimulated restoration efforts, but these have often overlooked the importance of maintaining the evolutionary potential of restored populations by minimizing the reduction in genetic diversity that typically accompanies restoration. In an experiment simulating a small-scale restoration, we tested the effectiveness of a buoy-deployed seeding technique to maintain genetic diversity comparable to the seed source populations. Seeds from three extant source populations in San Francisco Bay were introduced into eighteen flow-through baywater mesocosms. Following seedling establishment, we used seven polymorphic microsatellite loci to compare genetic diversity indices from 128 shoots to those found in the source populations. Importantly, allelic richness and expected heterozygosity were not significantly reduced in the mesocosms, which also preserved the strong population differentiation present among source populations. However, the inbreeding coefficient F IS was elevated in two of the three sets of mesocosms when they were grouped according to their source population. This is probably a Wahlund effect from confining all half-siblings within each spathe to a single mesocosm, elevating F IS when the mesocosms were considered together. The conservation of most alleles and preservation of expected heterozygosity suggests that this seeding technique is an improvement over whole-shoot transplantation in the conservation of genetic diversity in eelgrass restoration efforts.
authors.affiliation: Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Ort
authors.affiliation: Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America.
authors.forename: C Sarah
authors.initials: CS
authors.lastname: Cohen
authors.affiliation: Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America.
authors.forename: Katharyn E
authors.initials: KE
authors.lastname: Boyer
authors.affiliation: Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Reynolds
authors.affiliation: Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America.
authors.forename: Sheh May
authors.initials: SM
authors.lastname: Tam
authors.affiliation: Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, United States of America.
authors.forename: Sandy
authors.initials: S
authors.lastname: Wyllie-Echeverria
mesh_terms: D003247:Conservation of Natural Resources; D018744:DNA, Plant; D014644:Genetic Variation; D005828:Genetics, Population; D018895:Microsatellite Repeats; D035962:Zosteraceae / Q000235:genetics*
chemical_list: D018744:DNA, Plant