Preprint volume - SIBM

Pre-print Volume - Posters
Topic 1: BIODIVERSITY AND CONSERVATION SCIENCE: CONTRIBUTING TO MANAGEMENT
I. LOCCI, M. ESPA, F. PALMAS, A.A. PENDUGIU, P. PESCI, A. SABATINI
Department of Animal Biology and Ecology, University of Cagliari, Via T. Fiorelli, 1 - 09126 Cagliari, Italy.
ilocci@uniss.it
BIODIVERSITY INDEX EVOLUTION
IN SHALLOW WATER AREAS OF SARDINIAN SEAS (10-100 M)
EVOLUZIONE DEGLI INDICI DI BIODIVERSITÀ
NELLA FASCIA COSTIERA DEI MARI SARDI (10-100 M)
Abstract – Biological diversity is considered an important factor for ecosystem stability. The aim of this
study is to examine the temporal evolution of classical biodiversity indexes for shallow waters (10-100 m)
demersal assemblages in specific locations of the Sardinian seas, which have been subject to different
fishing pressure over the past 14 years (1994-2007). Our results indicate that fishing pressure appeared to
affect the diversity of shallow waters species, showing different biodiversity index reactions on different
levels of fishing effort. The validity and reliability of this index as a measure of environmental stress and its
potential use for the monitoring of demersal ecosystem is then discussed.
Key-words: demersal assemblages, Sardinia, biodiversity.
Introduction - The high concentration of human population near coasts and the
oceans’ productive coastal margins, strongly affects marine ecosystems and its
resources (Halpern et al., 2008). Industrial fishing in particular can have both direct
and indirect consequences on marine systems (Fogarty et al., 1998; Greenstreet and
Hall, 1996), including effects on species diversity. Several studies have underlined the
role of biodiversity in ecosystem functioning (Worm et al., 2006; Hector and Bagchi,
2007). In the light of the above, come out the importance of biological diversity, and
the development of further tools for monitoring its status should be considered
imperative. The aim of this study is to examine the answer of biodiversity indexes in
consequence of fleet evolution, on shallow waters demersal assemblages.
Materials and methods – Data were collected over 1994-2007 period, within the
framework of the international MEDITS research programme. The year 2002 was
excluded due to a sensible delay in starting the survey. Only the 10-100 m depth range
were considered. Species abundances data were used to calculate Shannon’s index
(H’), species richness (lnS) and Pielou’s evenness (J’). Fishing effort were evaluated
by means of Regione Autonoma della Sardegna fleet archives. These data regarded the
number of trawlers (