Preprint volume - SIBM

Pre-print Volume - Oral presentations
Topic 1: BIODIVERSITY AND CONSERVATION SCIENCE: CONTRIBUTING TO MANAGEMENT
Conclusions – Results of the comparison between PITs and visual quadrats highlight a
high variability among quadrats that hides the differences existing among sampling
sites in zones subjected to a different protection regime. To overcame this limit a
higher number of replicates is necessary, with a consequent increase in the amount of
time spent underwater. On the contrary, PITs have a larger cost/time effectiveness,
exhibit a lower variability among replicates and, because of their larger sampling size,
should be better candidates to detect differences at larger spatial scales (Parravicini et
al., 2009). The MDS plot also ordinates PIT replicates in a way that reflects the
zonation of the MPA. However, the institution of the Isola di Bergeggi MPA is too
recent, while a high number of studies (Claudet et al., 2008 and references therein)
suggest that several years are necessary to make protection effects detectable. Our
sampling sites were located along a inshore-offshore gradient, and the zonation of the
‘Isola di Bergeggi’ MPA exactly superimposes over such a gradient. This might cause
a problem in the future monitoring programs to discriminate protection effects from
environmental constrains: a more appropriate design will be necessary to disentangle
inshore-offshore and protection effects. Actually, visual quadrats and PITs are two
complementary sampling techniques, because the former is able to detect the
variability on the small scale, while the latter on the large scale.
When comparing cover data with frequency data no significant differences between
the two descriptors are found, both being able to collect the same information on
benthic assemblages. However, we advocate the adoption of frequency to characterize
benthic communities because it requests a comparatively shorter time for collecting
data.
References
BIANCHI C.N., PRONZATO R., CATTANEO-VIETTI R., BENEDETTI-CECCHI L., MORRI C.,
PANSINI M., CHEMELLO R., MILAZZO M., FRASCHETTI S., TERLIZZI A., PEIRANO A.,
SALVATI E., BENZONI F., CALCINAI B., CERRANO C., BAVESTRELLO G. (2004) –
Mediterranean marine benthos: a manual of methods for its sampling and study. Hard bottoms.
Biol. Mar. Mediterr., 11: 185 215.
CLAUDET J., OSEMBERG C.W., BENEDETTI-CECCHI L., DOMENICI P., GARCÍA-
CHARTON J.A., PÉREZ-RUSAFA A., BADALAMENTI F., BAYLE-SEMPERE J., BRITO
A., BULLERI F., CULIOLI J.M., DIMECH M., FALCÓN J.M., GUALA I., MILAZZO M.,
SÁNCHEZ-MECA J., SOMERFIELD P.J., STOBART B., VENDEPERRE F., VALLE C.,
PLANES S. (2008) – Marine reserves: size and age do matter. Ecology Letters, 11: 481-489.
PARRAVICINI V., MORRI C., CIRIBILLI G., MONTEFALCONE M., ALBERTELLI G.,
BIANCHI C.N. (2009) - Size matters more than method: visual quadrats vs photography in
measuring human impact on Mediterranean rocky reef communities. Estuarine, Coastal and Shelf
Science, 81: 358-367.
Work partially done within the frame of the research project ‘The impacts of biological invasions and
climate change on the biodiversity of the Mediterranean Sea’ (Italy–Israel co-operation, Italian
Ministry of the Environment). Data were collected thanks to an agreement between DipTeRis and the
MPA Authority Comune di Bergeggi.
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
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