Characterization of the Bulrushes


Bulrushes - les Oudinières (photo credit : CCIN)


The characterization of the Bulrushes (habitat related to the reed bed and dominated by the Bulrush that grows in brackish lagoons) and the search for Dark Spreadwings is carried out on the entire LIFE perimeter defined on the island of Noirmoutier on an area of 1600 ha. This study was not conducted on the Marais Breton or on the Guérande and Mès marshes.


This action allows you to:

  • Characterize the bulrushes (number, state of conservation) and identify potentially interesting sites for the Leste with great stigmas; Refine and update knowledge on the habitats of the Natura 2000 site under the Habitats Directive.
  • Have an inventory of the population of Dark Spreadwings on the Île de Noirmoutier.
  • Determine sites that could be the subject of restoration and management work in favor of Dark Spreadwings.


The study began in March 2019 with a first field trip for the mapping of the Bulrushes between March and May 2019. A second field visit was made between May and the end of June 2019 for the identification of the Leste with great stigmas. An interim report was sent in January 2020.

A new field visit will be made between mid-May and the end of June 2020 for the identification of the Leste with great stigmas on the bulrush pools considered to be the most favorable.

A final report is expected by December 2020.


The first results show 117 bulrushes present throughout the study area.

At the end of this 1st analysis, a 2nd analysis was set up by comparing the salinities of the different basins with those of the RNN des Marais de Müllembourg (area with the highest numbers of Leste). This work made it possible to determine the basins considered most favorable for the reception of Leste with great stigmas to target prospecting.

Thus, among the 117 sites identified, 23 sites were selected to search for the Leste with great stigmas in June 2019. The species was observed on 12 sites with a total number of 1505 individuals.

Bulrushes  mapping of île de Noirmoutier (source : CCIN)


Leste with great stigmas results, prospecting 2019 (source : CCIN)