Maerl Bed Conservation: Successes and Failures

Most ecoregions lack data on maerl distribution and ecological status, so this needs fundamental research for conservation. Brittany, NW France, is an exception and has extensive research on maerl species, associated biodiversity, human-induced impacts and protection efforts. Breton maerl habitats host exceptionally high species richness and functional diversity, surpassing all other coastal habitats in the region. The meiofauna and microflora of maerl beds and the role of these habitats as carbon stores remain poorly known. Bans on direct exploitation in Europe have led to environmental improvements, although maerl extraction has begun in other regions of the world. In Europe, serious maerl conservation problems persist, particularly due to scallop and clam dredging, eutrophication and mariculture impacts. Not enough has been done to curb these issues, which are proven to severely degrade maerl, its biodiversity and ecosystem functions. Conservation measures for maerl beds should be strengthened and codesigned with local stakeholders as these habitats take millennia to form and are inadequately protected by current strategies.