Preprint volume - SIBM

Pre-print Volume - Posters
Topic 1: BIODIVERSITY AND CONSERVATION SCIENCE: CONTRIBUTING TO MANAGEMENT
Chlorophyta 17,7%, Ochrophyta 20,8%), while 169 species were identified in the today
samples (Rhodophyta 73,6%, Chlorophyta 15,5%, Ochrophyta 10,9%). As shown in Fig. 2,
in both data set the taxon Rhodophyta is the richest in species, with an increase after 80
years. On the contrary, Chlorophyta and mainly Ochrophyta decrease. In particular, number
of Ochrophyta species is halved after 80 years.
Fig. 2 - Floristic comparison between 1927-2008. Fig. 3 - Comparision of corographyc groups between 1927-2008.
Confronto floristico tra il 1927 e 2008. Confronto dei gruppi corografici tra 1927 e 2008.
Only 40 species are shared by both the data set, being 191 the species exclusively found by
Funk and 129 those exclusively present in today samples. Among the shared species, 5 are
endemic (Balliella cladoderma, Halymenia floresia, Nithophyllum flabellatum,
Nithophyllum punctatum, Peyssonnelia squamaria). Other endemic species are exclusive of
single data set (33 in the Funk’s one, 26 in the today one). The allochthonous species are
totally different in the two data-set: 2 in Funk’s (Acanthophora nayadiformis, Hypnea
spinella) and 3 in the today one (Acrothamnion preisii, Asparagopsis armata, Caulerpa
racemosa). The comparison of corographyc spectra is shown in Fig. 3. On the overall, the
dominant corological groups are the same in both data-set, with the dominance of
Mediterranean species, that slightly decrease in time. In general, an increase of warm water
species (Tropical Atlantic-Boreal, Tropical Indo-Atlantic and Indo-Atlantic) and a decrease
of cold water species (Atlantic-boreal, Atlantic-Pacific, Circum-Boreal and Circum-
Austral) were recorded.
Conclusions – Several differences arise from the comparison of the two data-set, 80 years
distant in time. Probably, the lower number of species found today is due to a lower number
of investigated samples and sites and to different collecting techniques; on the other side,
modern direct sampling procedures are more efficient than ancient indirect ones. However,
the increase of anthropogenic impacts cannot be excluded, also on the basis of a drastic
decrease of Ochrophyta species, mainly of the genus Cystoseira (Serio et al., 2006), and of
an increase of Rhodophyta, due to an increase of water column turbidity. The influence on
the algal associations of the recent and invasive colonization by the allochthonous species
Caulerpa racemosa could also be taken into account for these changes, but must be better
studied in the future. The analysis of chorographic spectra also seems to sustain the
anthropogenic disturbance hypothesis, together with co-occurring changes in climatic
conditions, enhancing the presence of warm water species. In conclusion, an evident
decrease of biodiversity was recorded in the Gaiola Marine Protected Area after 80 years,
with a rearrangement of species in the main chorographic group, due to both climatic and
edaphic (anthropogenic) factors. The presence of a Marine Protected Area, by reducing the
anthropogenic impact, may enhance local biodiversity in the future.
References
FUNK G. (1927) - Die Algenvegetation des Golfs von Neapel. Pubb. Staz. Zoologica di Napoli, 7 (Suppl.): 1-320.
SERIO D., ALONGI G., CATRA M., CORMACI M., FURNARI G. (2006) - Change in the benthic algal flora of
Linosa Island (Straits of Sicily, Mediterranean Sea). Botanica Marina, 48: 135-144.
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
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