Tracing the introduction history of the brown seaweed Dictyota cyanoloma (Phaeophyceae, Dictyotales) in Europe

Dictyota cyanoloma has recently been described from the Mediterranean Sea and Macaronesia but doubt had arisen as to whether this species was truly native in Europe. The species is mainly found on non-natural substrata (harbour walls, marinas, boat hulls, etc.), strongly suggesting that it is an int...

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Bibliographic Details
Published in:European Journal of Phycology
Main Authors: Steen, Frederique, Aragay, Joana, Zuljevic, Ante, Verbruggen, Heroen, Mancuso, Francesco Paolo, Bunker, Francis, Vitales, Daniel, Gómez Garreta, Amelia, De Clerck, Olivier
Format: Article in Journal/Newspaper
Language:English
Published: 2017
Subjects:
Biology and Life Sciences
Alien species
cryptogenic species
Dictyota cyanoloma
herbarium species
mitochondrial DNA
MEDITERRANEAN SEA
NORTH-ATLANTIC
PHYLOGENETIC ANALYSES
SPECIES DELIMITATION
GENETIC DIVERSITY
SARGASSUM-MUTICUM
ALLELIC RICHNESS
MARINE-ALGAE
INVASIONS
GENUS
Cornwall
North Atlantic
Online Access:https://biblio.ugent.be/publication/8518478
http://hdl.handle.net/1854/LU-8518478
https://doi.org/10.1080/09670262.2016.1212998
https://biblio.ugent.be/publication/8518478/file/8518479
Description
Summary:Dictyota cyanoloma has recently been described from the Mediterranean Sea and Macaronesia but doubt had arisen as to whether this species was truly native in Europe. The species is mainly found on non-natural substrata (harbour walls, marinas, boat hulls, etc.), strongly suggesting that it is an introduction. Molecular sequence information from historical herbarium samples proves the presence of D. cyanoloma in the Adriatic Sea as early as 1935. Since approximately the year 2000, however, the number of records as well as the geographic range of the species has expanded significantly. The presentday distribution of D. cyanoloma occupies most of the Mediterranean Sea, Macaronesia, NW Africa and southern Portugal, but recent records from Galicia and SW England (Falmouth, Cornwall) indicate that the species is rapidly expanding northward. Collections from Australia demonstrated that the species is also present from Perth in Western Australia, over much of the southern Australian coastline up to Minnie Water in New South Wales. Phylogenetic analyses resolve D. cyanoloma in a sister clade to a previously unreported Australian Dictyota species. Analysis of genetic diversity of the mitochondrial markers (nad6-nad11 and atp9-orf11) reveals that even though Australian populations contain a much higher haplotype richness, European populations are also fairly diverse. Furthermore, only two out of 25 haplotypes are shared between both regions. These somewhat counterintuitive results could be indicative of a more complicated introduction history.

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