Dynamics of Seagrass Stability and Change

Duarte, Carlos M.; Fourqurean, James W.; Krause‐Jensen, Dorte; Olesen, Birgit

doi:10.1007/978-1-4020-2983-7_11

Cited by 38 publications

(43 citation statements)

References 132 publications

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“…Our initial prediction for the Norwegian populations was low genotypic diversity (i.e. presence of a few large genets/clones), a characteristic of isolation and reduced sexual reproduction (Duarte et al 2006) typically present in marginal populations such as those in the northern Baltic (Reusch et al 1999), the Black Sea (Olsen et al 2004) and the southern-most distribution in Portugal (Billing ham et al 2003). To the contrary, only 1 of the 15 sampled locations, an intertidal river outlet at Sør-Lenangen Nord with 5 fixed differences, was dominated by large genets/clones.…”

Section: Clonal Diversity and Population Structurementioning

confidence: 99%

“…Meadows may be heterogeneous as a consequence of temporal admixture events of repeated recruitment through time (originally proposed by Petit et al 2003for oaks, Becheler et al 2010; limited dispersal of pollen and seeds, leading to patchiness (Hämmerli & Reusch 2003); and local habitat selection (Oetjen & Reusch 2007, Oetjen et al 2010, Winters et al 2011. Alternatively, they can be homogeneous as a consequence of dominance by a few large genets/clones (Reusch et al 1999, Coyer et al 2008) and limited recruitment (Duarte et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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Eelgrass Zostera marina populations in northern Norwegian fjords are genetically isolated and diverse

Olsen¹,

Coyer

Stam³

et al. 2013

Mar. Ecol. Prog. Ser.

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Populations along the northern boundary of a marine species' distributional range in the NE Atlantic are expected to harbor lower standing genetic variation as a consequence of postglacial expansion following the last glacial maximum. Founder events and marginal habitat availability may render the edge populations more vulnerable to anthropogenic stress and less capable of rapid adaptation to global climate change, a concern for conservation and management. We analyzed meadow architecture, persistence and connectivity within and among 15 locations (600 samples genotyped with 8 microsatellite loci) in 3 fjords in Troms County, Norway (69°N). Whereas global mean allelic diversity (standardized for sample size) was in accordance with previous studies using the same markers, more extensive sampling revealed a broader range of allelic richness (mean = 2.85; range = 1.84 to 4.21) in the regional pool. Genotypic diversity was typically high, whereas large genets were rare (2 out of 15 locations). Population differentiation (F ST ) was 2 to 6 times higher between fjords than within fjords. A Bayesian (STRUCTURE) analysis also strongly supported the genetic distinctness of each fjord. Although 9 locations within the 60 km long Balsfjord were connected by gene flow, demographic connectivity may actually be low, as fixed differences were observed at 6 of the 9 locations, along with significantly positive inbreeding coefficients and strong substructure. Overall, our results suggest that these northern, leading-edge meadows are healthy, but vigilance is required to avoid further losses. Fjord-level management, especially of the larger fjords, will be sufficient to capture the range of variation.

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Section: Clonal Diversity and Population Structurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Eelgrass Zostera marina populations in northern Norwegian fjords are genetically isolated and diverse

Olsen¹,

Coyer

Stam³

et al. 2013

Mar. Ecol. Prog. Ser.

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“…As it is known to promote high concentrations of ammonium and sulfide in the porewater (Hauxwell et al, 2001;Short, 1983a;Smolders and Roelofs, 1995), both factors represent important biogeochemical stressors and are expected to influence seagrass expansion processes at a global scale. Although the occurrence of patches is a natural phenomenon in seagrass meadows (Duarte et al, 2006a), the level of patchiness is strongly increasing as a result of various human activities (Bostrom et al, 2006).…”

Section: Ecological Implicationsmentioning

confidence: 99%

“…Patches are very dynamic and normally ensure recovery of seagrass meadows (Duarte et al, 2006b). As we seek to preserve these constantly changing systems (preservation paradox; (Pickett and White, 1985)), it is vital to gain a better understanding of the effects of stressors on system dynamics.…”

Section: Ecological Implicationsmentioning

confidence: 99%

“…Patches expand through shoot expansion, mainly through horizontal elongation of rhizomes at the patch edges (Duarte et al, 2006a;Marba and Duarte, 1998;Olesen and Sand-Jensen, 1994;Vermaat, 2009). Their shoot densities increase exponentially (self-accelerating) with increasing patch age and size (Bostrom et al, 2006;Sintes et al, 2005;Vermaat, 2009;Vidondo et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

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Toxic effects of increased sediment nutrient and organic matter loading on the seagrass Zostera noltii

et al. 2014

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As a result of anthropogenic disturbances and natural stressors, seagrass beds are often patchy and heterogeneous. The effects of high loads of nutrients and organic matter in patch development and expansion in heterogeneous seagrass beds have, however, poorly been studied. We experimentally assessed the in situ effects of sediment quality on seagrass (Zostera noltii) patch dynamics by studying patch (0.35 m diameter) development and expansion for 4 sediment treatments: control, nutrient addition (NPK), organic matter addition (OM) and a combination (NPK+OM).OM addition strongly increased porewater sulfide concentrations whereas NPK increased porewater ammonium, nitrate and phosphate concentrations. As high nitrate concentrations suppressed sulfide production in NPK+OM, this treatment was biogeochemically comparable to NPK. Sulfide and ammonium concentrations differed within treatments, but over a 77 days period, seagrass patch survival and expansion were impaired by all additions compared to the control treatment.Expansion decreased at porewater ammonium concentrations >2000 mol L -1 .Mother patch biomass was not affected by high porewater ammonium concentrations as a result of its detoxification by higher seagrass densities. Sulfide 2 concentrations >1000 mol L -1 were toxic to both patch expansion and mother patch. We conclude that patch survival and expansion are constrained at high loads of nutrients or organic matter as a result of porewater ammonium or sulfide toxicity.

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2015

Aquaculture Ecosystems

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Dynamics of Seagrass Stability and Change

Cited by 38 publications

References 132 publications

Eelgrass Zostera marina populations in northern Norwegian fjords are genetically isolated and diverse

Eelgrass Zostera marina populations in northern Norwegian fjords are genetically isolated and diverse

Toxic effects of increased sediment nutrient and organic matter loading on the seagrass Zostera noltii

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