Genetic characterization of Zostera noltii seagrass populations along the Atlantic Moroccan Coast and the Canary Island.

Abstract

Seagrass meadows provide an essential ecological service in coastal ecosystems worldwide, although they are sensitive to many human factors having been documented a serious global regression. Along the Atlantic Moroccan Coast we found 5 coastal lagoons with maximum environmental interest char- acterized by the presence of intertidal seagrass Zostera noltii meadows that shelter great biodiversity throughout the year (Larache, Moulay Bousselham, Sidi Moussa, Oualidia and Nayla). In the Canary Is- land, only one single Z. noltii population has been located on the coast of Lanzarote (Arrecife), which has been included in the “Canary Island Catalogue of Endangered Species” as “threatened with extinction” (BOC 2001/097). In order to suggest future management strategies that promote the conservation of these highly sensitive and valuable areas, the present project has studied the genetic characterization and the connectivity between Moroccan and Canarian populations (0111-TECHMARAT-2-A, POCTEFEX- FEDER). Special handling deserves the single Lanzarote population to establish a restoration guidelines for its urgently recovery. 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 supported the clustering of Z. noltii subpopulations into four groups corresponding to four different geographical regions: R1-Northern Morocco (Larache and Moulay Bousselham), R2-Central Morocco (Oualidia and Sidi Moussa), R3- Southern Morocco (Nayla) and R4-Canary Island (Lanzarote). 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. Several recommendations to effectively restore the remaining Lanzarote population are also suggested, such as the employment of alternative restoration methods (e.g. seeds and seedlings cultivation), and the election of an appropriate starting plant material according to its genetic variability and genetic relation to recipient population.