Page 4 - Espinosa_alii_2013
P. 4

The marine limpet Patella ferruginea  269

               1,000
                   (a)                           (b)

                100


                 10


                 1
               1,000
                   (c)                           (d)

                100


                 10


                 1
               1,000
                   (e)                           (f)

                100


                 10


                 1
               1,000
                   (g)                           (h)
                                                                              FIG. 2 Size frequency distribution of
                100
                                                                              P. ferruginea (on a logarithmic scale) for
                                                                              each site at which .10 specimens were
                 10                                                           collected (Supplementary Table S1):
                                                                              (a) Asinara (Site 10), (b) Zembra
                                                                              archipelago (data pooled for Sites 51–55),
                 1                                                            (c) Capo Testa (25), (d) Galeria (1),
                   0–1 1–2 2–3 3–4 4–5 5–6 6–7 7–8 8–9 9–10  0–1 1–2 2–3 3–4 4–5 5–6 6–7 7–8 8–9 9–10
                                                                              (e) Kelibia (45), (f ) El Haouaria (44),
                                                                              (g) Porto Rafael (24), (h) Olbia (18).

           TABLE 2 One-way ANOVA for the differences in size between  appearing in the upper half of the graph (Fig. 3). SIMPROF
           populations of P. ferruginea. Only the eight populations where .10  analysis showed three clusters: one of small populations at
           individuals were recorded were included in this analysis. Results of  frequently visited sites (less protected) on Corsica, Sardinia
           the Student–Newman–Keuls test are ordered by mean size from  and mainland Tunisia, a second of mainly protected sites
           high to low.
                                                              (both on natural and artificial substrates), and a third of sev-
           Source of variation  SS  df   MS   F      P        eral North African populations from the Strait of Gibraltar
           Between populations  357.70 7  51.10 11,156  ,0.001  to the Zembra archipelago in the Siculo-Tunisian strait.
           Within populations  4,672.01 1,020  4.58           PERMANOVA analysis indicated that protection (as a
           Total           5,029.71 1,027                     result of inaccessibility) influenced the size frequency
                                                              distribution of the populations, whereas the type of sub-
           Student–Newman–Keuls test: Asinara.Capo Testa 5 Zembra 5  strate (natural vs artificial) had no significant influence on
           Galeria 5 Porto Rafael 5 Olbia 5 Kelibia 5 El Haouaria.
                                                              population structure (Table 3).

              Multivariate analyses indicated differences in population
                                                              Discussion
           structure with the level of exploitation. Populations in areas
           free of human visitation (protected) partially segregate from  The main conclusion of this study is the vulnerable situation
           the human-affected sites in the MDS analysis, mainly  of P. ferruginea. Although previous studies identified the


           © 2013 Fauna & Flora International, Oryx, 48(2), 266–275

           http://journals.cambridge.org    Downloaded: 14 Mar 2014                        IP address: 150.214.246.48
   1   2   3   4   5   6   7   8   9