as promoted by the GEF-UNDP-IMO GloFouling Partnership project
(https://www.glofouling.imo.org, accessed July 2022). At the moment, the management
of fouling on recreational boats is based on guidelines applied on voluntary basis by
boat owners, and the management of fouling communities inhabiting ports has been
poorly considered, while the design of artificial infrastructures able to limit NIS
colonization is an aspect that needs further investigation (Hopkins et al., 2021). Elton’s
biotic resistance hypothesis (Elton, 1958) suggests that communities rich in native
species should be more resistant to NIS settlement. Several experiments have been
carried out to test this hypothesis, however reporting contradictory results (e.g.,
Stachowicz et al., 2002; Rius & McQuaid, 2009; Gestoso et al., 2014).
This study, inspired by the experiment carried out by Gestoso et al. (2017) in
Macaronesia, aimed at testing the biotic resistance hypothesis on Mediterranean fouling
communities through a transplant experiment.
Materials and methods
This study was carried out in three sites in the Gulf of La Spezia (Ligurian Sea, Italy) at
different level of ‘impact’, in terms of NIS propagule pressure and occurrence: one lowimpact site (Palmaria, a small island within the regional natural park of Porto Venere,
with very low NIS richness) and two high-impact sites (the marinas of Le Grazie and
Fezzano, with high NIS richness). During the transplant procedures from Palmaria to
the two marinas, only 20 out of 25 panels were found.
Fig.1: Map of the study area. Numbers indicate the panels initially deployed in each site,
while in brackets the number of panels located in each site after the transplant
experiment, specifying the treatment assigned: C (control, in Palmaria); T (transplanted
panels from Palmaria to the marinas); M (no-transplanted panels in marinas).
In April 2019 a total of 25 PVC panels were deployed in the three sites, arranged as
follow: 15 panels in Palmaria, 5 in Le Grazie and 5 in Fezzano). After three months of
immersion (July), all panels were retrieved, photographed, and rapidly analysed in the
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
30
(https://www.glofouling.imo.org, accessed July 2022). At the moment, the management
of fouling on recreational boats is based on guidelines applied on voluntary basis by
boat owners, and the management of fouling communities inhabiting ports has been
poorly considered, while the design of artificial infrastructures able to limit NIS
colonization is an aspect that needs further investigation (Hopkins et al., 2021). Elton’s
biotic resistance hypothesis (Elton, 1958) suggests that communities rich in native
species should be more resistant to NIS settlement. Several experiments have been
carried out to test this hypothesis, however reporting contradictory results (e.g.,
Stachowicz et al., 2002; Rius & McQuaid, 2009; Gestoso et al., 2014).
This study, inspired by the experiment carried out by Gestoso et al. (2017) in
Macaronesia, aimed at testing the biotic resistance hypothesis on Mediterranean fouling
communities through a transplant experiment.
Materials and methods
This study was carried out in three sites in the Gulf of La Spezia (Ligurian Sea, Italy) at
different level of ‘impact’, in terms of NIS propagule pressure and occurrence: one lowimpact site (Palmaria, a small island within the regional natural park of Porto Venere,
with very low NIS richness) and two high-impact sites (the marinas of Le Grazie and
Fezzano, with high NIS richness). During the transplant procedures from Palmaria to
the two marinas, only 20 out of 25 panels were found.
Fig.1: Map of the study area. Numbers indicate the panels initially deployed in each site,
while in brackets the number of panels located in each site after the transplant
experiment, specifying the treatment assigned: C (control, in Palmaria); T (transplanted
panels from Palmaria to the marinas); M (no-transplanted panels in marinas).
In April 2019 a total of 25 PVC panels were deployed in the three sites, arranged as
follow: 15 panels in Palmaria, 5 in Le Grazie and 5 in Fezzano). After three months of
immersion (July), all panels were retrieved, photographed, and rapidly analysed in the
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
30