Management of invasive species in wetlands protected areas of the Natura 2000 network: case studies in Sardinia

Wetlands represent an important part of Europe’s biodiversity. They provide ideal conditions for a wide variety of flora and fauna. However, despite their importance, wetlands are disappearing and among the most threatened ecosystems within the Natura 2000 network. Invasive alien species (IAS) are one of the main causes of biodiversity loss and species extinction and their spread is currently favoured by climate change and globalisation, which in parallel reduces the resilience of endangered habitats like wetlands. Molentargius salt marshes and Santa Gilla lagoon are the most important wetlands in southern Sardinia and among the largest ecosystems of natural wetlands in Europe. They are located in urban contexts and on the outskirts of the city of Cagliari and they have been historically modified and used by humans. Nonetheless, they are still conserving relevant aspects, in terms of habitats and species and they are recognized for their conservation importance by the Ramsar Convention and protected by different regional (Molentargius-Saline Regional Park), national and international policies (two SACs: “Stagno di Molentargius e territori limitrofi” and “Stagno di Cagliari, Saline di Macchiareddu, Laguna di Santa Gilla”; two SPAs: “Saline di Molentargius” and “Stagno di Cagliari”). In recent years, the two wetlands have been affected by several projects concerning actions aimed at eradicating and controlling IAS. These projects were financed by the managing authority of the protected areas with own and regional funds (Molentargius-Saline Regional Park) and by European funds within the Prioritized Action Frameworks (PAFs) to implement the EU-wide Natura 2000 network (action 6.5.1 POR FESR 2014-2020) (Metropolitan City of Cagliari). Eradication and control of IAS were necessary to give back space to native species, to support the recovery of natural vegetation, and also facilitate, wherever the eradication took place, the reintroduction of native species through renaturation of wetland areas. The eradication actions were performed only by expert and authorized staff, since IAS are inside natural and sensitive habitats, to avoid harming native animal and plant species. Both hand and mechanical eradication practices were carried out and, at the same time, their effectiveness was monitored. An economic estimate was also made to evaluate the work effort in terms of number of workers, tools used and time consuming for eradication. The results obtained are important from an application point of view because they provide useful information for the conservation of autochthonous species and natural habitats and for the management of IAS in wetlands.