Plant and arthropod communities in Myriophyllum aquaticum (Vell.) Verdc. invaded and uninvaded waters in a Mediterranean wetland (Tuscany, Central Italy)

Biological invasions have been recognised as one of the most dramatic threats to biodiversity. Invasive Alien Species (IAS) can exert detrimental effects on the invaded ecosystem, generating both ecological and socioeconomic impacts. Myriophyllum aquaticum (Vell.) Verdc. is a well-known invasive species, native of South America, which is nowadays widespread in many countries. It was introduced in the alien range mostly as an ornamental plant in ponds and aquaria. In Tuscany, it has been recorded in the area of Lake Porta where it shows an invasive behaviour, spreading across the network of canals around the lake. The study focused on the comparison of macrophytes and arthropod communities between the canals with vegetation dominated by native plants and those with a strong invasion of M. aquaticum. The sampling units were transects of 5x2 metres placed along the stream banks of several canals around the lake Porta. The first results show differences mainly in plant species richness and in floristic composition between invaded and uninvaded transects. Further analyses are still in progress to evaluate possible changes in the arthropod communities on M. aquaticum-dominated stands.