Combined genetic and habitat characterization as a management tool for Zostera noltii seagrass populations along the Atlantic Moroccan Coast

Abstract

Seagrass meadows provide an essential ecological service in coastal ecosystems worldwide, although they are sensitive to many environmental and human factors having been documented a serious global regression. Along the Atlantic Moroccan Coast we found 5 areas with maximum environmental interest as coastal lagoons characterized by the presence of intertidal seagrass Zostera noltii meadows that shelter great biodiversity throughout the year (Loukos estuary, Moulay Bousselham, Sidi Moussa, Oualidia and Naila´s Lagoon). In order to suggest future management strategies that promotes the conservation of these highly sensitive and valuable areas, the present work, which is conducted on the framework of TechMARAT´s project (0111_TECHMARAT_2_A, POCTEFEX-FEDER), has studied the genetic characterization and the connectivity between population to identify Management Units, while providing remote sensing tools to mapping the actual distribution of Z. noltii meadows. Zostera noltii populations are shown to be highly isolated due to low long and short-term gene flow and high distance between optimal habitats. Bio-geographical analysis (PCoA, NJ tree and STRUCTURE) supported the clustering of Z. noltii subpopulations into three groups corresponding to three different geographical regions: R1-Northern Morocco (Larache and Moulay Bousselham), R2-Central Morocco (Oualidia and Sidi Moussa) and R3-Southern Morocco (Nayla). The clear definition of seagrass clusters along the Atlantic Moroccan Coast should be considered for the future management of these spaces, defining Management Units that could be used to improve restoration techniques, avoiding translocation and mixing of very different populations (outbreeding depression), or to prioritize population units for conservation due to the limited economical resources. Additionally, we characterized their habitat through high-resolution satellite images and in situ fields surveys. The developed maps can be used by management agencies to identify and determined Z. noltii habitats that can serve as a starting point in conservation planning and to evaluated and monitored changes over time.