Invasive species

Biological monitoring

Presentation

This action concerns both the invasive exotic plant species (Baccharis halimifolia and the grass of Pampa Cortaderia selloana) and animal species (Nutria Myocastor coypus and Muskrat Ondatra zibethicus). This monitoring concerns all of the territories.

Goals

The objective is to assess the impact of actions implemented to combat invasive species present in the salt and salt marshes targeted by LIFE Sallina and degrading natural habitats such as lagoons and salt meadows.

Advancement

The follow-ups concerning the invasive exotic animal species are carried out throughout the duration of the project on all the territories.

For invasive exotic plant species, this monitoring will be carried out in 2021 for Noirmoutier Island, in 2022 for the Millac marshes and in 2023 for the Guérande and Mès marshes. Note that a detailed mapping of the distribution of Baccharis was carried out in 2018 on the marshes of the Presqu’île de Guérande and in 2016 on the Marsh of Millac.

Results

» Marshes of Guérande and Mès :

The trapping implemented in 2019 made it possible to capture 36 nutria (10 on the site of Careil-Mouzac and 26 on that of North-East Saillé).

In general, compared to freshwater marshes or certain rivers in the department, the populations are not very large in terms of numbers. However, individuals can settle in a sustainable manner and create damage to habitats and cause dysfunctions in the hydraulic management of the salt marshes exploited on the edge of the pilot sites.