The purpose is to study the effect of the American mink Neovison vison on native diversity, in order to establish a correct framework for the management and control of its populations, in order to preserve the natural biodiversity in the areas of action of the project.

The purpose is to study the effect of the American mink Neovison vison on native diversity, in order to establish a correct framework for the management and control of its populations, in order to preserve the natural biodiversity in the areas of action of the project.

The purpose of the initiative is to study the effects of the interaction of the American mink Neovison vison, with the ecosystem and native biodiversity (predation and competition relationships), through the methods of prospecting for tracks and indications, and trapping with capture and recapture, in areas with presence (two zones A and B) and absence of the invasive species (one zone C).

Through the data collected, the abundance of different carnivores, considered as competitors, and prey species, between the study areas will be compared. Different measures will also be taken, which will allow the study of both population parameters of the different species of carnivores captured, as well as reproductive parameters of the American mink.

By removing individuals in one of the study areas (zone B), it will be determined if it is possible to restore the balance in the dynamics of the ecosystem, broken by the presence of the invasive species, and it will be evaluated if trapping is a correct method for controlling American mink populations. All with the ultimate goal of laying the foundations for a future plan for the proper management of American mink populations.

The areas in which the project will be developed are the following:

Zone A: Llobregat and Gavarresa rivers, in the Bages region. It comprises two stretches of river, with a total of 20 km: Riera Gavarresa, from the municipality of Avinyó to its junction with the Llobregat, in Cabrianes; and Río Llobregat, from Balsareny to Navarcles. The section in total also runs through the municipalities of Artés, Sallent, Sampedor and Sant Fruitós de Bages.

Zone B: Fluvià river, in the regions of La Garrotxa, Pla de l’Estany and Alt Empordà. It comprises a 20 km stretch of river, from the municipality of Argelaguer, to the AP-7 bridge, in Báscara. It also runs through the municipalities of Besalú, Esponellà, Cresipà and Pontós.

Zone C: Francolí River, in the region of Conca de Barberá. It comprises a 20 km stretch of river, from the municipality of Espluga de Francolí to Picamoixons. It also runs through the municipalities of Montblanc, Vilaverd and La Riba.

The specific objectives are:

• To know the effects of the presence of the American mink on the diversity of native fauna, through the study of the competition and predation of this species on the organisms that share habitat with it.
• To delve into the biology of American mink reproduction in Catalonia (reproductive status, to determine the exact breeding season, and number of offspring per female, to determine the birth rate).
• To know the population structure (distribution in age classes) of the American mink and the different competing species and prey.
• To determine if it is possible to restore the balance prior to the presence of the American mink.
• To find out if trapping is an effective methodology for controlling American mink populations.
• Establish a framework for future actions of correct management, with the intention of solving the possible ecological and social problems caused by this species.