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Mediterranean Bioconstructions Along the Italian Coast 113

Ionian Seas. The few explorations of this long stretch of coast have revealed
very rich communities (e.g. Bo et al., 2011, 2012a,b). The south Adriatic
coast of Italy is very rich in bioconstructions and Posidonia, whereas these
are almost absent in the Central Adriatic, characterized by long stretches
of sandy coasts and bottoms where mainly Sabellaria reefs are present.
Fraschetti et al. (2008) remarked that bioconstructions are original and
vulnerable habitats that deserve absolute priority in conservation measures.
Bioconstructors, in fact, replace the original geological habitat and become
themselves a habitat that, even if they die, remains in place for some time,
but loses its most peculiar feature: life. Both the European and the Italian
authorities recognize this importance, since both nationally designated
MPAs and SCIs designated in Italian waters almost invariably comprise
either bioconstructions or Posidonia meadows or both.
The importance of some bioconstructions, especially coralligenous ones,
is more elusive than that of both tropical and cold-water coral formations,
where the corals are both the habitat and its benthic component. If corals
die, the perception of life disappears. Coralligenous formations, on the con-
trary, are the habitat for a wealth of spectacular living sponges, cnidarians,
bryozoans and ascidians that are not the primary “makers” of the substrate,
this role being played by coralline algae and bacterial mats. The “beauty” of
coral formations is seen in the corals, whereas the “beauty” of coralligenous
formations is seen in what covers the bioconstruction.
The distribution patterns of Italian coastal bioconstructions are quite well
known, but many gaps are still to be filled for the deep sea and for some
stretches of coast. The state of these formations must be continuously mon-
itored so as to assess their condition and, in case of deterioration, to develop
specifically tailored management options, even though they will be probably
insufficient if a full understanding of the processes that allow for their
persistence is not available. The knowledge of patterns, then, should be
upgraded with an improving knowledge of processes, as shown here with
connectivity models as a preliminary example.

6. CONCLUSIONS

The basic principle of guidelines to preserve bioconstructions, then, is
very simple: impacts affecting them must be identified and removed. This
can be straightforward for direct impacts, but global impacts such as climate
warming are more difficult to manage. Extensive mass mortalities of impor-
tant species that grow on coralligenous formations, such as sponges and sea