Conservation of Mediterranean wetlands: Interest of historical approach

The wetlands of North Africa are an endangered and invaluable ecological heritage. Some of these wetlands are now protected by various conservation statutes; which actual impact has not yet been reliably evaluated. This article aims to assess the conservation management (Nature Reserve and Ramsar site) of a protected Tunisian lake, Majen Chitane, by using palaeoecological, historical and modern data, and by comparing it with the unprotected lake Majen Choucha. While located in similar environments, these lakes are today home to very different flora. Baseline conditions reconstructed from literature indicate that both lakes were very similar until the 1950s, and comparable to the current state of Majen Choucha, housing rich oligotrophic plant communities. In the 1960s, at the time that cultivation of the adjacent peatland began, Majen Chitane underwent strong ecological changes as the initial oligotrophic plant, diatom and zooplankton communities were replaced by eutrophication-tolerant ones. Eutrophication led to the local extinction of 40–55% of the hydrophytic and temporary-pool plant species, including those characteristic of the Isoetion. Given the damages and despite the recent conservation status of the site, it's unlikely that Majen Chitane will undergo any natural regeneration. Restoring it would start with completely protecting the complex lake-peatland and re-introducing the locally extinct species from Majen Choucha. This work exemplifies the usefulness of connecting palaeoecological, historical and modern data for the conservation of Mediterranean wetlands. Les zones humides d’Afrique du Nord représentent un patrimoine écologique inestimable et menacé. Certaines sont aujourd’hui protégées par divers statuts de conservation, dont l’impact réel n’a pas encore été évalué de manière fiable. Cet article vise à évaluer la gestion conservatoire (Réserve Naturelle et site Ramsar) d’un lac tunisien protégé (Majen Chitane), à travers des données paléoécologiques, historiques et actuelles, par comparaison à un lac non protégé (Majen Choucha). Bien que situés dans des environnements similaires, ces deux lacs hébergent aujourd’hui des flores très différentes. La reconstruction de l’état de référence à partir des données de la littérature révèle que les deux sites étaient très similaires avant les années 1950, et comparables à l’état actuel de Majen Choucha : ils hébergeaient notamment de riches communautés végétales oligotrophes. Depuis les années 1960, sim