Zostera noltii in the Canary Islands: a genetic description for conservation purposes

Abstract

The extremely delicate situation affecting the seagrass Zostera noltii in the Canary Islands (listed as 'threatened with extinction') requires urgent measures to ensure its preservation. The genetic or genotypic description of populations and knowledge about their connectivity are important genetic issues that should be taken into account to accomplish appropriate conservation and restoration programmes, particularly for threatened habitats or species. Therefore, a genetic characterisation of the single remaining meadow located on the coast of Lanzarote was conducted using nine microsatellite loci, and its genetic relationship with the geographically closest Moroccan populations was studied for restoration purposes. Results showed that the Lanzarote population has recently suffered a significant reduction in effective population size and presents low levels of allelic or genotypic diversity in relation to other Z. noltii populations throughout its distribution range. Moreover, this population remains in an extremely isolated situation in which it lacks long-term gene flow with other Moroccan populations. These genetic factors, together with the lack of sexual reproduction (only vegetative growth via rhizomes has been reported) and high anthropogenic pressures, make the risk of extinction of this species in the Canarian archipelago more likely. Some considerations for future restoration plans for this valuable species are suggested.