Historical changes and inventory of macroalgae from Koenigshafen Bay in the northern Wadden Sea

• Published in: Exchange processes and long-term developments in the ecology of the List tidal basin in the northern Wadden Sea. Proceedings of the Ecosystem Research Project in the Schleswig-Holstein Wadden Sea (SWAP) Vol. 51; no. 3; pp. 321 - 341
• Main Authors: Schories, D, Albrecht, A, Lotze, H
• Format: Book Chapter
• Language: English
• Published: 01.01.1997
• Subjects: Callithamnion corymbosum; Enteromorpha; Gracilaria verrucosa; Marine; Sargassum muticum; ANE, Germany, Schleswig-Holstein, Sylt I., Koenigshafen Bay; ANE, Wadden Sea
• ISSN: 0174-3597

Knowledge on the distribution, abundance and species richness of intertidal macroalgae occurring on sandy and muddy flats of the German Wadden Sea is still incomplete. We summarize published and unpublished information available on the presence of macroalgae on the on tidal flats of Koenigshafen Bay (island of Sylt, North Sea), one of the more extensively studied areas of the Wadden Sea. A total of 46 green algal species, 36 brown algal species and 26 red algal species has been recorded within the last 120 years on soft and hard substrata of Koenigshafen Bay (disregarding species found unattached or drifting). Several of these species were only temporarily resident on the tidal flats. Today, at least 35 green, 15 brown and 12 red algal species occur within or close to Koenigshafen Bay. Significant long-term changes in species abundances have occurred in all three major groups of algae: Since the late 1970s, dense green algal mats dominated by Enteromorpha flexuosa, E. radiata and E. prolifera have occurred regularly on the intertidal flats, whereas a general decrease of brown and red algae has been documented. Two red algal species, Gracilaria verrucosa and its epiphyte Callithamnion corymbosum, were conspicuous members of the macro-flora until the middle of this century. Although still present in the 1980s, they have now disappeared completely. On the other hand, the brown alga Sargassum muticum has begun to colonize mussel beds. The causal background of long-term changes in the macroalgal flora of Koenigshafen Bay is discussed. Owing to substantial nomenclatural changes during the last 120 years, a revised species list with authors' names and synonyms is included.