Preprint volume - SIBM

Pre-print Volume – Oral presentations
Topic 3: INTEGRATED COASTAL ZONE MANAGEMENT
A. ROVERE, M. MONTEFALCONE, P. VASSALLO, C. PAOLI, M. VACCHI, C. MORRI,
C.N. BIANCHI, M. FIRPO, G. ALBERTELLI, M. FABIANO
Dip.Te.Ris., Università degli Studi di Genova, Corso Europa, 26 - 16132 Genoa, Italia.
alessio.rovere@unige.it
POSIDONIA OCEANICA THROUGH TIME:
MODERN AND PALEOECOLOGICAL PERSPECTIVES
FROM THE BERGEGGI - VADO LIGURE AREA (SV)
POSIDONIA OCEANICA NEL TEMPO: PROSPETTIVE MODERNE
E PALEOECOLOGICHE NELL’AREA BERGEGGI-VADO LIGURE (SV)
Abstract - Diachronic cartography and one sediment core in the Bergeggi-Vado Ligure area (NW
Mediterranean Sea) were used to assess, respectively, short-term and long term evolution of the Posidonia
oceanica meadow. A preliminary evaluation of its economic value has been performed.
Key-words: Posidonia oceanica, evolution, diachronic cartography, Ligurian Sea.
Introduction - The endemic Posidonia oceanica (L.) Delile is the most abundant
seagrass in the Mediterranean Sea, where it forms extensive meadows from the surface
down to 40 m depth and plays major ecological roles for coastal ecosystems and
generates important services for coastal population (Montefalcone, 2009 and reference
therein). Geomorphology of the coast is influenced by P. oceanica meadows that damp
the swell and form an obstacle to the movement of sediments on the bottom (Tigny et
al., 2007; Vacchi et al., 2010). Meadows also contribute to water oxygenation, keeping
the ecosystem healthy. The preservation of these functions implies economic benefits
for coastal areas (e.g. fisheries, tourism) not necessarily perceived by society and
ascribed by economy. Regression of P. oceanica meadows, due to both natural and
human effects, has been surely accelerating in recent decades. In the Ligurian Sea, for
instance, nearly 30% of the original meadow surface area has been lost in the 1960s,
during the period of rapid urban and industrial development occurred along the
Ligurian coast (Bianchi and Morri, 2000). The health and occurrence of P. oceanica
meadows along the coastline, and their change over time, can be seen as one of the
“reading keys” of the evolution of soft coasts: the diachronic cartography represents an
important tool for measuring temporal changes in term of percentage gain or loss of
meadow extension. Superimposed to short term changes, P. oceanica is believed to
have had its climatic optimum around 6000±2750 years BP (Mateo et al., 1997). In this
contribution we attempt to evaluate long (millennial) and short (decadal) term
evolution of P. oceanica in the Bergeggi-Vado Ligure area (Ligurian Sea). This
evolution has been tentatively translated in monetary terms aiming at making clear
related economic outcomes.
Materials and methods - The extension and typology of the P. oceanica meadows in
the study area has been drawn in Bianchi and Peirano (1990), MSS-ENEA (1991),
Diviacco and Coppo (2006) using Side Scan Sonar (SSS). Cartographic outputs have
been vectorised at the same resolution scale (1:25000) and processed with GIS to
obtain concordance maps. One core (V1) was made in the study area and different
sections containing dead matte of P. oceanica have been dated through 14 C at Beta
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
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