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- Källström, Björn, 1970, et al.
(author)
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Seed rafting as a dispersal strategy for eelgrass (Zostera marina)
- 2008
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In: Aquatic Botany. - : Elsevier BV. - 0304-3770. ; 88:2, s. 148-153
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Journal article (peer-reviewed)abstract
- Using observations, experiments and model simulations we investigate the possibility and range of long-distance dispersal by seed rafting in eelgrass, Zostera marina, at the Swedish west coast. A field experiment showed that the breaking strength of post-flowering rhipidia decreased significantly over a 30-day period, indicating that ontogenetic changes of the morphology facilitate dislodgement of the rhipidia at the optimal time for dispersal. We recorded positive buoyancy of detached post-flowering rhipidia for at least 26 days. Finally, we found evidence for sexual reproduction via seeds in the study area. These results, together with field measurements of wind-driven surface-transport velocity of rhipidia and wind data from 7 years, allowed us to model a dispersal potential of up to 150 km in one season along the Swedish west coast, which corresponds well with published estimates of dispersal potential from both observational and genetic studies. The results add to evidence that rafting of seeds on floating reproductive shoots is an important dispersal strategy for eelgrass, allowing for colonisation of new areas and for recolonisation after die-back events. (c) 2007 Elsevier B.V. All rights reserved.
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- Nyqvist, Anna, 1961, et al.
(author)
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Dynamics of Seagrass Meadows on the Swedish Skagerrak Coast
- 2009
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In: Ambio. - : Royal Swedish Academy of Sciences. - 0044-7447 .- 1654-7209. ; 38:2, s. 85-88
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Journal article (peer-reviewed)abstract
- Seagrasses have declined in many places around the world, and the Swedish Skagerrak coast is no exception. Between the 1980s and 2000, the cover of eelgrass (Zostera marina L.) on the Swedish Skagerrak coast decreased about 60%. In the present study, the sites that were investigated in the 1980s and 2000 were revisited (1655 ha) in 2003 and 2004 to investigate long and short term temporal and spatial differences in eelgrass coverage. The distribution of eelgrass was mapped from a small boat using an aquascope and a GPS receiver. No variation in total (about 150 km) or regional (about 20 km) eelgrass cover was found between 2000 and 2004, but there were substantial changes (both losses and gains) in meadow size on a local (less than about 2 km) scale. The results have implications for management of shallow soft bottoms, particularly because it was shown that even though no eelgrass is found in a single survey in a specific area, there could be eelgrass growing there in the following years.
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| 4. |
- Nyqvist, Anna, 1961, et al.
(author)
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Föränderliga ålgräsängar
- 2007
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In: Havsmiljön - aktuell rapport om miljötillståndet i Kattegatt, Skagerrak och Öresund. ; 2007:December
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Journal article (other academic/artistic)abstract
- Utbredningen av ålgräs i Bohuslän minskade med ca 60 % från 1980 till 2000. Hur har det gått sedan? För att försöka lära oss mer om ålgräsets dynamik gjordes ytterligare undersökningar av ett antal ålgräsängar utmed den svenska västkusten. Resultatet av dessa fältundersökningar har sedan använts i en modell som kan användas för att studera konsekvenser av mänskliga störningar och av olika strategier för att skydda dessa områden.
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