title: Distribution, structure and function of Nordic eelgrass(Zostera marina)ecosystems: implications for coastal management and conservation.
abstract: This paper focuses on the marine foundation eelgrass species,Zostera marina, along a gradient from the northern Baltic Sea to the north-east Atlantic. This vast region supports a minimum of 1480 km2eelgrass (maximum >2100 km2), which corresponds to more than four times the previously quantified area of eelgrass in Western Europe.Eelgrass meadows in the low salinity Baltic Sea support the highest diversity (4-6 spp.) of angiosperms overall, but eelgrass productivity is low (<2 g dw m-2d-1) and meadows are isolated and genetically impoverished. Higher salinity areas support monospecific meadows, with higher productivity (3-10 g dw m-2d-1) and greater genetic connectivity. The salinity gradient further imposes functional differences in biodiversity and food webs, in particular a decline in number, but increase in biomass of mesograzers in the Baltic.Significant declines in eelgrass depth limits and areal cover are documented, particularly in regions experiencing high human pressure. The failure of eelgrass to re-establish itself in affected areas, despite nutrient reductions and improved water quality, signals complex recovery trajectories and calls for much greater conservation effort to protect existing meadows.The knowledge base for Nordic eelgrass meadows is broad and sufficient to establish monitoring objectives across nine national borders. Nevertheless, ensuring awareness of their vulnerability remains challenging. Given the areal extent of Nordic eelgrass systems and the ecosystem services they provide, it is crucial to further develop incentives for protecting them. © 2014 The Authors.Aquatic Conservation: Marine and Freshwater Ecosystemspublished by John Wiley & Sons, Ltd.
authors.affiliation: Åbo Akademi University, Department of Biosciences, Environmental and Marine Biology Åbo, Finland.
authors.forename: Christoffer
authors.initials: C
authors.lastname: Boström
authors.affiliation: Göteborg University, Department of Marine Ecology, Sven Lovén Centre for Marine Science Fiskebäckskil, Sweden.
authors.forename: Susanne
authors.initials: S
authors.lastname: Baden
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Experimental Ecology of Food Webs Düsternbrooker Weg 20, Kiel, Germany.
authors.forename: Anna-Christina
authors.initials: AC
authors.lastname: Bockelmann
authors.affiliation: Aarhus University, Department of Bioscience Frederiksborgvej 399, Roskilde, Denmark.
authors.forename: Karsten
authors.initials: K
authors.lastname: Dromph
authors.affiliation: Department of Biology, University of Oslo Oslo, Norway.
authors.forename: Stein
authors.initials: S
authors.lastname: Fredriksen
authors.affiliation: Åbo Akademi University, Department of Biosciences, Environmental and Marine Biology Åbo, Finland.
authors.forename: Camilla
authors.initials: C
authors.lastname: Gustafsson
authors.affiliation: Aarhus University, Department of Bioscience Vejlsøvej 25, Silkeborg, Denmark.
authors.forename: Dorte
authors.initials: D
authors.lastname: Krause-Jensen
authors.affiliation: Estonian Marine Institute, University of Tartu Tallinn, Estonia.
authors.forename: Tiia
authors.initials: T
authors.lastname: Möller
authors.affiliation: Roskilde University, Department of Environmental, Social and Spatial Change (ENSPAC) Universitetsvej 1, Roskilde, Denmark.
authors.forename: Søren Laurentius
authors.initials: SL
authors.lastname: Nielsen
authors.affiliation: Aarhus University, Department of Bioscience Ole Worms Allé, Århus C, Denmark.
authors.forename: Birgit
authors.initials: B
authors.lastname: Olesen
authors.affiliation: University of Groningen, Marine Benthic Ecology & Evolution group, Centre for Ecological and Evolutionary Studies Nijenborgh 7, Groningen, Netherlands.
authors.forename: Jeanine
authors.initials: J
authors.lastname: Olsen
authors.affiliation: Göteborg University, Department of Marine Ecology, Sven Lovén Centre for Marine Science Fiskebäckskil, Sweden.
authors.forename: Leif
authors.initials: L
authors.lastname: Pihl
authors.affiliation: Norwegian Institute for Water Research Gaustadalléen 21, Oslo, Norway.
authors.forename: Eli
authors.initials: E
authors.lastname: Rinde
keywords: Zostera marina; biological organization; conservation; eelgrass food web; eutrophication; genetic diversity; trajectories