DNA-based monitoring: A pilot study on autonomous reef monitoring structures (ARMS) in the North Sea region.

Here we evaluated a genetic monitoring protocol for potential applications in regional level status assessments of benthic diversity across in the North Sea Region (NSR). For this study, we chose an established method for passive sampling of hard-bottom communities using Autonomous Reef Monitoring Structures (ARMS). We created thirteen sample events in five coastal observatories throughout Denmark, Norway, Sweden, and Belgium. Field work was carried out by each partner, while the laboratory work, data management as well as analyses were performed centralized. Sequence analysis of the collected samples resulted in identification of 599 species across the five observatories.
Sixty percent of the identified species belonged to metazoans, while the remaining forty percent consisted of plants, fungi as well as single- and multicellular eukaryotic taxa. A scan against the ecological checklists for sensitive, alien, and red-listed species resulted in observations of 76 sensitive
species, 24 alien species, and 4 vulnerable or near-threatened species across the five observatories. Our results show that benthic communities can be monitored by independent parties while data can be analyzed on a regional scale. Cost comparison with diver-based monitoring methods showed that the tested method is not more expensive than conventional monitoring. We conclude that ARMS provide a mature and cost-effective method for genetic monitoring of benthic hard bottom habitats in the North Sea Region and recommend implementation of the method in national monitoring programs as well as environmental impact assessments in order to better assess the health status and change of coastal ecosystems and the biological response to human activities in the ocean.