Preprint volume - SIBM

Pre-print Volume - Oral presentations
Topic 1: BIODIVERSITY AND CONSERVATION SCIENCE: CONTRIBUTING TO MANAGEMENT
G. GATTI, M. MONTEFALCONE, V. PARRAVICINI, C. MORRI, M. CHIANTORE, C.N. BIANCHI
DipTeRis, Department for the study of the Territory and its Resources, University of Genoa,
Corso Europa, 26 - 16132 Genoa, Italy.
gatti.giulia25@gmail.com
MONITORING THE “ISOLA DI BERGEGGI” MARINE
PROTECTED AREA: A COMPARISON BETWEEN
POINT INTERCEPT TRANSECTS AND VISUAL QUADRATS
IL MONITORAGGIO DELL'AREA MARINA PROTETTA
“ISOLA DI BERGEGGI”: POINT INTERCEPT TRANSECTS
E QUADRATI VISUALI A CONFRONTO
Abstract – Differences between two visual sampling methods, Point Intercept Transects (PITs) and Visual
Quadrats, were investigated on hard bottom subtidal benthic assemblages in the “Isola di Bergeggi” MPA
(Ligurian Sea). Results showed that PITs detect differences among sites better than quadrats.
Key-words: quadrat, PIT, Marine Protected Area, hard bottom, Mediterranean Sea.
Introduction – Monitoring activities were carried out in 2009 in the “Isola di
Bergeggi” MPA (Ligurian Sea, NW Mediterranean), instituted in 2007 (D.M.
7/5/2007), aiming to evaluate the condition of hard bottom assemblages. During the
kick off of these activities we sampled benthic assemblages using two visual methods
that enable to survey areas of different size, in order to compare their performance
when investigating differences among sites and zones subjected to a distinct protection
regime and to assess the most efficient method for monitoring a MPA.
Materials and methods – Surveys were carried out in May 2009 in a total of six sites:
two in zone A (Sites 5, 6), two in zone B (Sites 3, 7) and two in zone C (Sites 1, 2) at
5 m depth (Fig. 1). Two visual methods were applied for sampling benthic
assemblages: the Point Intercept Transect (PIT) and the Visual Quadrat (Bianchi et al.,
2004). Three 10 m long replicates of PITs and six replicates of quadrats (50 cm x
50 cm) were examined, totalling 18 PITs and 36 quadrats. Data from quadrats were
collected either as percent cover and relative frequency.
PIT and quadrat cover and frequency data for each species (or higher ranked taxon)
were used to calculate Bray Curtis Similarity and compared using multivariate analyses
(Multidimentional Scaling, SIMPER) to investigate similarity among sites. On the
basis of the number of species (or taxa) obtained in each replicate the Dispersion
Coefficient was computed, in order to analyse effects of the size of sampling area on
the dispersion between replicates.
Results – The comparison between PITs and quadrats shows small differences in the
number of species detected (PITs: 48 species; quadrats: 52 species). The MDS plot
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
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