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Alien species on Sylt

Alien species on Sylt. Seaweeds. Maria Redeker, Carolin Barz, Olga Kolychalow. Native Phaeophycea (brown alga). http://www.arkive.org/species/ARK/plants_and_algae/Fucus_vesiculosus/. Fucus vesiculosus. Gracilaria vermiculophylla Since 2002 in Wadden Sea. Sargassum muticum

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Alien species on Sylt

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  1. Alien species on Sylt Seaweeds Maria Redeker, Carolin Barz, Olga Kolychalow

  2. Native Phaeophycea (brown alga) http://www.arkive.org/species/ARK/plants_and_algae/Fucus_vesiculosus/ Fucus vesiculosus

  3. Gracilaria vermiculophylla Since 2002 in Wadden Sea Sargassum muticum Since 1993 on Sylt Alien Algae on Sylt http://www.algaebase.org/search/species/detail/?species_id=4417 http://www.issg.org/database/species/ecology.asp?si=727&fr=1&sts=sss

  4. Aims • Do the species differ in length? • Does any species prefer any specific attachment type? • Does the length of the alga depend on the attachment type? • Is there any competition between native and non-native species? • Does the length reflect any habitat provision? • May the non-native species have any effect on biodiversity?

  5. Study sites • Oyster bed • Former military area • Boulders • Oyster farm http://www.welt-atlas.de/datenbank/karten/karte-1-227.gif

  6. Methods • Measuring length of thalli • Determine attachment type

  7. Length of macroalgae

  8. Length of F. vesiculosus relating to attachment type

  9. Length of G. vermiculophylla relating to attachment type

  10. Length of S. muticum relating to attachment type

  11. Results • No obvious dependence of length and attachment type • Attachment type does not influence growth • Not possible to state if species prefer any specific attachment type

  12. Discussion • Notably longer thalli and complexity of structure of both invasive species may imply a larger surface, i.e. habitat • S. muticum supports twice as many species (local) as F.vesiculosus • S. muticum provides habitat for species which otherwise would be rare or absent (e.g. several species of red algae)

  13. Discussion • No competition between S. muticum and F. vesiculosus as they occur at different water levels • G. vermiculophylla and F. vesiculosus occur in the same spots

  14. Conclusions • Up to now no replacement of native species recorded in SE Wadden Sea • Seem to have positive effects on habitat formation and biodiversity • As non-native algae species are expected to increase in abundance, this might affect competitive ability of native species

  15. Conclusions • Species have the potential to alter the ecology of Wadden Sea • Attempts to eradicate S. muticum likely to fail • Due to insufficient knowledge it is not possible to predict the future effects • More research is needed !!!!!!

  16. Thank you for your attention!!

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