Rétablissement des communautés de libellules (Odonata) dans les tourbières du Jura neuchâtelois (Suisse)

Abstract

Restoration of dragonfly communities (Odonata) in the peatlands of the Jura Mountains of Neuchâtel (Switzerland). Over the course of the 20th century, the peatlands of the valleys of La Brévine and Les Ponts-de-Martel lost over 90% of their surface area due to the industrial exploitation of peat. Restoration work undertaken between 1996 and 2018 increased the number of bodies of water in these areas from 240 to 341 and their surface area from 1.3 to 10.1 hectares. Odonates have been regularly monitored in several of these wetland areas since 2005. In 2017 and 2018, an intensive monitoring program identified 38 species. Observations made between 1938 and 2018 included a total of 52 species, or over two-thirds of Swiss Odonata fauna. Nine of these species are found on the national Red List. Species strictly associated with peatlands benefitted from restoration measures; their numbers have increased since 2005. Leucorrhinia pectoralis is now established in twelve peatlands out of fifteen and L. albifrons, one of the rarest dragonflies in Switzerland, currently reproduces in a peatland that was the subject of intensive restoration. Discoveries of Aeshna subarctica and Ceriagrion tenellum may hint at future colonization of this region by these species. Given such positive results, the canton of Neuchâtel will continue its restoration program for at least the next five years. Only the coordinated management of diverse types of wetland habitats will allow for the survival of the most demanding species.