Assessing and forecasting the effects of submersion on biodiversity. A method to implement an ecological-quality indicator in a context of coastal realignment and rising sea levels

Marianne Debue (1) , Lucille Billon (1) , Olivier Brivois (2) , Rémy Poncet (1) , Yorick Reyjol (1)

1 PatriNat - Patrimoine naturel
2 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

In the context of climate change and sea-level rise, coastal realignment consists in reopening polders to marine waters to favor 'nature-based' mitigation measures. Such operations have consequences on biodiversity, which vary depending on the parameters studied and site features. In this study, a multimetric indicator aiming to evaluate and predict the potential ecological quality of sites undergoing a realignment operation was developed. This indicator is based on the combination of two tools, (i) a biological-capacity matrix to assess the importance of different habitats of a defined typology for taxonomical, patrimonial and functional parameters; (ii) habitat maps obtained by photointerpretation for past habitats, by machine learning using space-borne imagery for present habitats and by forecasting using submersion models for future habitats. The indicator is presented in the form of a radar chart, with each axis corresponding to one parameter of the biological-capacity matrix and highlighting its different values for different coastal-realignment scenarios or different time horizons.

Mots clés: Saltmarsh; Habitats; Machine learning; Marine submersion; Sea-level rise; Climate change

Domaines: Sciences de la Terre; Sciences de l'environnement; Biodiversité et Ecologie

Marianne Debue, Lucille Billon, Olivier Brivois, Rémy Poncet, Yorick Reyjol. Assessing and forecasting the effects of submersion on biodiversity. A method to implement an ecological-quality indicator in a context of coastal realignment and rising sea levels. Ecological Indicators, 2022, 142, pp.109216. ⟨10.1016/j.ecolind.2022.109216⟩. ⟨hal-03844486⟩