Modelling the response of Antarctic marine species to environmental changes. Methods, applications and limitations.

• Main Author: Guillaumot, Charlène
• Other Authors: Danis, Bruno, Saucède, Thomas, Gypens, Nathalie, IRISSON, Jean-Olivier IJ, HILL, Nicole NH, MORMEDE, Sophie MS, Navarro, Nicolas
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Universite Libre de Bruxelles 2021
• Subjects: Sciences exactes et naturelles; model performance; Southern Ocean; ecological modelling; physiological model; species distribution modelling; dispersal model; Antarctic; Antarc*
• Online Access: http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/327073; https://dipot.ulb.ac.be/dspace/bitstream/2013/327073/4/Thesis_C_GUILLAUMOT.pdf; https://dipot.ulb.ac.be/dspace/bitstream/2013/327073/3/TABLE_OF_CONTENTS_THESIS_C_GUILLAUMOT.docx; https://dipot.ulb.ac.be/dspace/bitstream/2013/327073/5/ContratDiGuillaumot.pdf

Among tools that are used to fill knowledge gaps on natural systems, ecological modelling has been widely applied during the last two decades. Ecological models are simple representations of a complex reality. They allow to highlight environmental drivers of species ecological niche and better understand species responses to environmental changes. However, applying models to Southern Ocean benthic organisms raises several methodological challenges. Species presence datasets are often aggregated in time and space nearby research stations or along main sailing routes. Data are often limited in number to correctly describe species occupied space and physiology. Finally, environmental datasets are not precise enough to accurately represent the complexity of marine habitats. Can we thus generate performant and accurate models at the scale of the Southern Ocean ?What are the limits of such approaches ?How could we improve methods to build more relevant models ?In this PhD thesis, three different model categories have been studied and their performance evaluated. (1) Mechanistic physiological models (Dynamic Energy Budget models, DEB) simulate how the abiotic environment influences individual metabolism and represent the species fundamental niche. (2) Species distribution models (SDMs) predict species distribution probability by studying the relationship between species presences and the environment. They represent the species realised niche. (3) Dispersal lagrangian models predict the drift of propagules in water masses. Results show that physiological models can be developed for marine Southern Ocean species to simulate the metabolic variations in link with the environment and predict population dynamics. However, more data are necessary to highlight detailed physiological contrasts between populations and to accurately evaluate models. Results obtained for SDMs suggest that models generated at the scale of the Southern Ocean and future simulations are not relevant, given the lack of data available to characterise ...