cylindracea exhibited little intra- and interannual variability: from 2008, the year of its
first finding, its cover has increased from 4% to about 12% in 2012-17 and remained
around this figure in the second period of monitoring, 2018 to 2021. In the circalittoral
zone (Fig. 1b), its cover resulted more variable within and among years and tended to
decrease over time: in 2008 its cover was 21%, to decrease to around 15% in 2012-17.
Notwithstanding wide interannual variability, cover returned to 15% in 2021. A reduction
in C. cylindracea cover was observed at all depths in 2019, after the severe storm that
occurred in the autumn of 2018, which caused the removal of algal thalli.
Fig. 1: Mean (± se) cover of Caulerpa cylindracea on the rocky reefs of the Portofino MPA,
in three time periods: 2008, when it was first recorded in the area; 2012-17, first period of
yearly monitoring (see Morri et al., 2019, for detail); and 2018 to 2021, recent monitoring
results. (a) Infralittoral zone (1 m to 20 m); (b) Circalittoral zone (21 m to 45 m)
Conclusions
Although primarily designed to manage fisheries, MPAs have been proven to be capable
of improving the health status of benthic habitats (Bianchi et al., 2022). Nonetheless, our
results show that the protection regime of Portofino MPA has been ineffective in keeping
reef communities in such a state of health as to enable them to prevent biological
invasions. In only 13 years, C. cylindracea has colonized the entire area and is now fully
established on the rocky reefs of Portofino MPA. Long-term monitoring remains the only
way to illustrate the naturalization trend of C. cylindracea and its consequences on the
native communities of Portofino MPA.
Bibliography
BIANCHI C.N., AZZOLA A., COCITO S., MORRI C., OPRANDI A., PEIRANO A.,
SGORBINI S., MONTEFALCONE M. (2022) - Biodiversity monitoring in Mediterranean
Marine Protected Areas: scientific and methodological challenges. Diversity, 14 (1): 43.
MONTEFALCONE M., MORRI C., PARRAVICINI V., BIANCHI C.N. (2015) - A tale of two
invaders: divergent spreading kinetics of the alien green algae Caulerpa taxifolia and Caulerpa
cylindracea. Biol. Invasions, 17: 2717–2728.
MORRI C., MONTEFALCONE M., GATTI G., VASSALLO P., PAOLI C., BIANCHI C.N. (2019) -
An alien invader is the cause of homogenization in the recipient ecosystem: a simulation-like
approach. Diversity, 11 (9): 146.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
106
first finding, its cover has increased from 4% to about 12% in 2012-17 and remained
around this figure in the second period of monitoring, 2018 to 2021. In the circalittoral
zone (Fig. 1b), its cover resulted more variable within and among years and tended to
decrease over time: in 2008 its cover was 21%, to decrease to around 15% in 2012-17.
Notwithstanding wide interannual variability, cover returned to 15% in 2021. A reduction
in C. cylindracea cover was observed at all depths in 2019, after the severe storm that
occurred in the autumn of 2018, which caused the removal of algal thalli.
Fig. 1: Mean (± se) cover of Caulerpa cylindracea on the rocky reefs of the Portofino MPA,
in three time periods: 2008, when it was first recorded in the area; 2012-17, first period of
yearly monitoring (see Morri et al., 2019, for detail); and 2018 to 2021, recent monitoring
results. (a) Infralittoral zone (1 m to 20 m); (b) Circalittoral zone (21 m to 45 m)
Conclusions
Although primarily designed to manage fisheries, MPAs have been proven to be capable
of improving the health status of benthic habitats (Bianchi et al., 2022). Nonetheless, our
results show that the protection regime of Portofino MPA has been ineffective in keeping
reef communities in such a state of health as to enable them to prevent biological
invasions. In only 13 years, C. cylindracea has colonized the entire area and is now fully
established on the rocky reefs of Portofino MPA. Long-term monitoring remains the only
way to illustrate the naturalization trend of C. cylindracea and its consequences on the
native communities of Portofino MPA.
Bibliography
BIANCHI C.N., AZZOLA A., COCITO S., MORRI C., OPRANDI A., PEIRANO A.,
SGORBINI S., MONTEFALCONE M. (2022) - Biodiversity monitoring in Mediterranean
Marine Protected Areas: scientific and methodological challenges. Diversity, 14 (1): 43.
MONTEFALCONE M., MORRI C., PARRAVICINI V., BIANCHI C.N. (2015) - A tale of two
invaders: divergent spreading kinetics of the alien green algae Caulerpa taxifolia and Caulerpa
cylindracea. Biol. Invasions, 17: 2717–2728.
MORRI C., MONTEFALCONE M., GATTI G., VASSALLO P., PAOLI C., BIANCHI C.N. (2019) -
An alien invader is the cause of homogenization in the recipient ecosystem: a simulation-like
approach. Diversity, 11 (9): 146.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
106