title: Coast-wide recruitment dynamics of Olympia oysters reveal limited synchrony and multiple predictors of failure.
abstract: Recruitment of new propagules into a population can be a critical determinant of adult density. We examined recruitment dynamics in the Olympia oyster (Ostrea lurida), a species occurring almost entirely in estuaries. We investigated spatial scales of interannual synchrony across 37 sites in eight estuaries along 2,500 km of Pacific North American coastline, predicting that high vs. low recruitment years would coincide among neighboring estuaries due to shared exposure to regional oceanographic factors. Such synchrony in recruitment has been found for many marine species and some migratory estuarine species, but has never been examined across estuaries in a species that can complete its entire life cycle within the same estuary. To inform ongoing restoration efforts for Olympia oysters, which have declined in abundance in many estuaries, we also investigated predictors of recruitment failure. We found striking contrasts in absolute recruitment rate and frequency of recruitment failure among sites, estuaries, and years. Although we found a positive relationship between upwelling and recruitment, there was little evidence of synchrony in recruitment among estuaries along the coast, and only limited synchrony of sites within estuaries, suggesting recruitment rates are affected more strongly by local dynamics within estuaries than by regional oceanographic factors operating at scales encompassing multiple estuaries. This highlights the importance of local wetland and watershed management for the demography of oysters, and perhaps other species that can complete their entire life cycle within estuaries. Estuaries with more homogeneous environmental conditions had greater synchrony among sites, and this led to the potential for estuary-wide failure when all sites had no recruitment in the same year. Environmental heterogeneity within estuaries may thus buffer against estuary-wide recruitment failure, analogous to the portfolio effect for diversity. Recruitment failure was correlated with lower summer water temperature, higher winter salinity, and shorter residence time: all indicators of stronger marine influence on estuaries. Recruitment failure was also more common in estuaries with limited networks of nearby adult oysters. Large existing oyster networks are thus of high conservation value, while estuaries that lack them would benefit from restoration efforts to increase the extent and connectivity of sites supporting oysters.
authors.affiliation: Elkhorn Slough National Estuarine Research Reserve, 1700 Elkhorn Road, Royal Oaks, California, 95064, USA.|Department of Ecology and Evolutionary Biology, University of California, 100 Shaffer Road, Santa Cruz, California, 95060, USA.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Wasson
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, 100 Shaffer Road, Santa Cruz, California, 95060, USA.|Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, Beaufort, North Carolina, 28516, USA.
authors.forename: Brent B
authors.initials: BB
authors.lastname: Hughes
authors.affiliation: Schmid College of Science and Technology, Department of Biological Sciences, Chapman University, Orange, California, 92866-1005, USA.|Department of Biological Science (MH-282), California State University, P.O. Box 6850, Fullerton, California, 92834-6850, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Berriman
authors.affiliation: Smithsonian Environmental Research Center, 3152 Paradise Drive, Tiburon, California, 94920, USA.|San Francisco Bay National Estuarine Research Reserve, 3152 Paradise Drive, Tiburon, California, 94920, USA.|Department of Environmental Science and Policy, University of California, One Shields Avenue, Davis, California, 95616, USA.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Chang
authors.affiliation: San Francisco Bay National Estuarine Research Reserve, 3152 Paradise Drive, Tiburon, California, 94920, USA.|Department of Environmental Science and Policy, University of California, One Shields Avenue, Davis, California, 95616, USA.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Deck
authors.affiliation: Skagit County Marine Resources Committee, 1800 Continental Place, Mount Vernon, Washington, 98273, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Dinnel
authors.affiliation: Elkhorn Slough National Estuarine Research Reserve, 1700 Elkhorn Road, Royal Oaks, California, 95064, USA.
authors.forename: Charlie
authors.initials: C
authors.lastname: Endris
authors.affiliation: Department of Biological Science (MH-282), California State University, P.O. Box 6850, Fullerton, California, 92834-6850, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Espinoza
authors.affiliation: Vancouver Island University, 900 Fifth Street, Nanaimo, British Columbia, V9R 5S5, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Dudas
authors.affiliation: San Francisco Bay National Estuarine Research Reserve, 3152 Paradise Drive, Tiburon, California, 94920, USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Ferner
authors.affiliation: Department of Environmental Science and Policy, University of California, One Shields Avenue, Davis, California, 95616, USA.
authors.forename: Edwin D
authors.initials: ED
authors.lastname: Grosholz
authors.affiliation: Department of Marine and Environmental Sciences, Marine Science Center, Northeastern University, Nahant, Massachusetts, 01908, USA.
authors.forename: David
authors.initials: D
authors.lastname: Kimbro
authors.affiliation: Department of Biology, University of Washington, Seattle, Washington, 98195-1800, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Ruesink
authors.affiliation: Department of Biology, University of Washington, Seattle, Washington, 98195-1800, USA.
authors.forename: Alan C
authors.initials: AC
authors.lastname: Trimble
authors.affiliation: The Nature Conservancy, 821 SE 14th Avenue, Portland, Oregon, 97214, USA.
authors.forename: Dick
authors.initials: D
authors.lastname: Vander Schaaf
authors.affiliation: Smithsonian Environmental Research Center, 3152 Paradise Drive, Tiburon, California, 94920, USA.|Department of Environmental Science and Policy, University of California, One Shields Avenue, Davis, California, 95616, USA.
authors.forename: Chela J
authors.initials: CJ
authors.lastname: Zabin
authors.affiliation: Department of Biological Science (MH-282), California State University, P.O. Box 6850, Fullerton, California, 92834-6850, USA.
authors.forename: Danielle C
authors.initials: DC
authors.lastname: Zacherl
mesh_terms: D063147:Animal Distribution; D000818:Animals; D002170:Canada; D010125:Ostreidae / Q000502:physiology*; D010140:Pacific Ocean; D011157:Population Dynamics; D014481:United States
keywords: biogeography; bivalves; conservation; population cycles; population ecology; regional studies; restoration