The Venice lagoon is the Italian hotspot of non-indigenous species (NIS) in the Mediterranean Sea. A critical revision of the alien macroalgae estimates the actual number of introductions in 28 taxa, 54% of the total introduced macroalgae present along the Italian coasts; many cryptogenic species reported in the previous lists have been excluded, whereas a few taxa such as Ulva fasciata/Ulva lactuca require confirmation. Out of these 29 NIS, 5 are Chlorophyceae, 6 Phaeophyceae, 17 Rhodophyceae; 4 taxa are invasive (Gracilaria vermiculophylla, Sargassum muticum, Undaria pinnati fida, Codium fragile subsp. fragile ) and 3 potentially invasive (Hypnea flexicaulis, Grateloupia turuturu, Heterosiphonia japonica ). Other NIS (Agardhiella subulata, Solieria filiformis) are invasive only in the Venice Lagoon or nearby (lagoons of the Po Delta and the pond Pialassa della Baiona in Emilia-Romagna Region). G. vermiculophylla, A. subulata, S. filiformis and H. flexicaulis are able to grow also by free floating or in soft substrata and present a high invasion risk. The other taxa are benthic species whose presence depends on the availability of hard substrata. S. muticum and U. pinnatifida have raised public concern after having colonized the banks of the historical centre of Venice and Chioggia; however, their biomass is negligible: ca. 0.2 ktonnes for Undaria and 6-7 ktonnes for Sargassum, accounting for ca. 5-7% of the total lagoon macroal gal biomass. The most invasive species is surely G. vermiculophylla , first recorded in 2008 in some confined areas (Lago dei Teneri) of the central lagoon and now (2014) occurring between Venice, the industrial area and Campalto. In the latter area it has completely replaced the laminar Ulvaceae that in July 2013 had triggered an anoxic crisis. Despite the invasive behavior of G. vermiculophylla , it is not considered to adversely affect the environment; furthermore this species is studied for agar, sugar or alcohol production.
Spreading and production of invasive alien macrophytes in the Venice Lagoon
Sfriso A.;Marchini A.;
2014
Abstract
The Venice lagoon is the Italian hotspot of non-indigenous species (NIS) in the Mediterranean Sea. A critical revision of the alien macroalgae estimates the actual number of introductions in 28 taxa, 54% of the total introduced macroalgae present along the Italian coasts; many cryptogenic species reported in the previous lists have been excluded, whereas a few taxa such as Ulva fasciata/Ulva lactuca require confirmation. Out of these 29 NIS, 5 are Chlorophyceae, 6 Phaeophyceae, 17 Rhodophyceae; 4 taxa are invasive (Gracilaria vermiculophylla, Sargassum muticum, Undaria pinnati fida, Codium fragile subsp. fragile ) and 3 potentially invasive (Hypnea flexicaulis, Grateloupia turuturu, Heterosiphonia japonica ). Other NIS (Agardhiella subulata, Solieria filiformis) are invasive only in the Venice Lagoon or nearby (lagoons of the Po Delta and the pond Pialassa della Baiona in Emilia-Romagna Region). G. vermiculophylla, A. subulata, S. filiformis and H. flexicaulis are able to grow also by free floating or in soft substrata and present a high invasion risk. The other taxa are benthic species whose presence depends on the availability of hard substrata. S. muticum and U. pinnatifida have raised public concern after having colonized the banks of the historical centre of Venice and Chioggia; however, their biomass is negligible: ca. 0.2 ktonnes for Undaria and 6-7 ktonnes for Sargassum, accounting for ca. 5-7% of the total lagoon macroal gal biomass. The most invasive species is surely G. vermiculophylla , first recorded in 2008 in some confined areas (Lago dei Teneri) of the central lagoon and now (2014) occurring between Venice, the industrial area and Campalto. In the latter area it has completely replaced the laminar Ulvaceae that in July 2013 had triggered an anoxic crisis. Despite the invasive behavior of G. vermiculophylla , it is not considered to adversely affect the environment; furthermore this species is studied for agar, sugar or alcohol production.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
