The distribution of the endemic brown alga
Fucus virsoides was assessed along the northern Adriatic
coastline. A high-resolution geographic information system
database was created using visual census methods to
identify the presence and abundance of algae, including
the geomorphology of the substrate. Samples of F. virsoides
were collected for analysis of the quantitative spatial
distribution. The abundance of F. virsoides was related
to several environmental variables, including the relative
exposure index (REI). The results support the hypothesis
that the distribution of F. virsoides in the Gulf of Trieste
is influenced mainly by the stability of mediolittoral
substrata, wave exposure and the vicinity of freshwater
inputs. Populations of this species are widespread in the
Gulf of Trieste. Many of them were found growing inside
small harbours or along a boatyard, where fluctuations in
salinity and nutrient concentrations are frequent. Therefore,
we conclude that F. virsoides cannot be considered
an ecological indicator for seawater pollution nor for climate
change, since it is subjected naturally to high pollution
levels and environmental variability.
