Species and synonym list of the German marine - Institut für ...

Introduction
Salinity and its variability, substrate availability and light climate are the key
factors governing the distribution of macrophyte species along the German coast
(LAKOWITZ 1929, KORNMANN & SAHLING 1977, NIELSEN et al. 1995). They can explain
together with local hydrodynamic conditions and biological factors the main portion of
species distribution (BUCAS et al. 2007).
In the last decades changes in distribution and diversity of macroalgae were
observed in German coastal waters. All water bodies bordering the German states,
Lower Saxony, Schleswig-Holstein, Mecklenburg-Western Pommerania and their
corresponding islands have been subjected to extremely high anthropogenic impacts
in the 20th century (ŁYSIAK-PASTUSZAK 2000; REISE et al. 2006). The nutrient input to
the coastal waters is high, especially via rivers and diffuse agricultural run-off
(BEHRENDT et al., 1999; STALNACKE et al. 1999). Consequently, the trophic status has
increased drastically during the last thirty years according to long-term monitoring
measurements (Nausch et al. 1999). The underwater light regime as well as the
substrate type have changed over time depending on the eutrophication of the water
bodies (SCHUBERT & FORSTER, 1997; NIELSEN et al. 2002). Both factors are important
for the composition and depth distribution of submerged macrophyte communities
(Van den Berg et al. 1998; GREVE & KRAUSE-JENSEN 2005; HAUXWELL et al. 2006) and
explain observed changes in all regions.
The arrival of new species from warmer regions and the invasion of alien
species due to human activities can increase species diversity on the one hand, but
risk dramatic changes in community structure on the other. Climate change
enhances the arrival of new species from warmer regions that formerly were not able
to survive. As the worldwide transport of merchandise on the oceans is steadily
increasing, so, too, is the transport of macroalgae spores and juvenile stages in the
ballast water. Two other vectors related to the arrival of alien species are aquaculture
farming and unfortunately also the escape of material from scientific research. Known
alien species from German coastal waters can form mono-specific stands in the
invaded habitats, potentially with persistent impact on the native assemblage
structure.
The aim of this work was the publication of a complete check-list and synonym
list for marine and brackish macroalgae for Germany including all invasive species
encountered during the last century as a basis for further research. We disclaim in
this publication any risk analysis for German macroalgae because this was already
done by SCHORIES et al. (1995) and is under current revision by the German Federal
Agency for Nature Conservation (Bundesamt für Naturschutz, BfN).
1 Study Area and Methods
North Germany is bordered on its Western side with the North Sea and on its
Eastern side with the brackish Baltic Sea. This geographical feature results in a
variety of water bodies, differing in macroalgae richness. Detailed description about
different water typologies for the North and Baltic Sea are given by GOSSELCK et al.
(2003). Due to the lack of distribution data for marine macrophytes we distinguish
here only between (1) the Eastern Frisian Wadden Sea, (2) the Northern Frisian
Wadden Sea, (3) the area around the Island of Helgoland, (4) the Western German
Baltic Sea from Flensburg to the island of Fehmarn and (5) the Eastern German
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