In my Phd-research I focus on the genus of submerged macrophytes Ruppia sp. Plants belonging to this genus are found in coastal and saline wetlands all over the world, where they are a key-stone species, being one of the very few angiosperms that can resist such high variations in water and salinity-levels. It’s simplified and slender morphology and high phenotypic diversity poses problems for its taxonomy and identification. Today, molecular markers derived from the chloroplast DNA and microsatellite markers can be used to help identification, but these new answers question our former knowledge about the different Ruppia species, their origins and their ecology.
Focusing on a Mediterranean wetland, the Camargue in the south of France, I am trying to solve the taxonomic and ecological questions this genus raises, by looking at it on a small scale. Microsatellites allow us to infer the relationships between the plants within this area and can help to solve questions about the origins of the plant (several introductions by e.g. birds or sea currents from other wetlands versus a single introduction event), about the underlying mechanisms of its (local) dispersal, about the possibility and history of hybridizations and about the distribution and co-occurrence of different Ruppia species. Combining microsatellites with experimental work helps answering ecological questions about the importance of genetic diversity in these species-poor systems (effects on the ecosystems resilience or its consequences for (micro-)invertebrates diversity) and the way of seed establishment and germination. These answers will allow us to gain a better understanding of the importance of Ruppia in these ecosystems, and the potential needs and methods for future conservation, as many of these coastal wetlands are threatened ecosystems.