Micro-endemism in New Caledonia : Characterization from freshwater zooplankton, identification of major explicative factors and submission of a functional ecology model

The biological, geological and climatic context of New Caledonia is particularly remarkable through the association of outstanding factors and conditions. Although of small area (approximately the same as the Pyrenees), the island is one of the major global biodiversity hotspots and possesses the greatest proportion of endemic species described on all french territories (56% according to the INPN, 2021). It has long been thought that this extraordinary biodiversity came from its dissociation from Australia 80 Ma ago followed by independant speciations in New Caledonia but it has been demonstrated that the island has been submerged until 37 Ma ago and would have known a later re-colonisation of terrestrial life. The tectonic event that led to the emergence of New Caledonia has also provoked the carriage of the Earth's mantle that created, after alteration, massifs rich in heavy metal that are under high mining exploitation pressure.

This thesis revolves around three main parts, the first two are paricularly focusing on the documentation and explanation of endemism and micro-endemism among zooplanktonic communities of neo-caledonian ponds. Indeed, ponds in New Caledonia are quite unknown and a preliminary work, carried out during my internship also within the BIOPAC team, suggests the existence of numerous species to discover and describe. The documentation of endemism and micro-endemism within these communities will unfold through the combination of genetic and morphologic approaches. From this documentation, several models (species niche models, predictive repartition models and extrapolation in high potential areas) will be constructed to caracterize major explicative factors of this phenomena in freshwater zooplanktonic communities.

These two first parts will allow an enrichment of the knowledge and understanding of neo-caledonian ecosystems and will constitute a basis to the establishment of the third and last major part of the thesis : the provision of methods and tools to study endemism and micro-endemism. This part of the thesis is particularly possible through the collaboration with the UMS Patrimoine Naturel and the french biodiversity data hub (Pôle National de Données de Biodiversité) and has emerged from several observations made in ecology and around biodiversity conservation sciences. In fact, great advances have been accomplished since the first main alerts on biodiversity loss in the 1960s : we have great quality research and expertise in these domains at a global scale, we have functional concepts and various, adaptable and practical methods. Yet, all these things are greatly under-used and would gain to be more transparent, reproducible and accessible. The idea with this part of the thesis is to make the findings and knowledge produced by this research directly actionable to protect ecosystems.