Monitoring ecological quality of coastal waters by the Nature Index (NI) – an integrated measure of biodiversity

On a request by the Norwegian Government, a comprehensive index aimed at monitoring state and trends across and within all aquatic and terrestrial ecosystems has been developed and implemented in Norway. The Nature Index (NI) synthesises information on biodiversity from a variety of sources into simple and easily-communicated forms. The index is composed of a series of indicators, each representing individual species or diversity measures standardized to a reference state, and combined and weighted for ecosystems or geographical regions. We present results for coastal waters. The data were assembled from plankton and benthos monitoring programmes, habitat mapping, fish stock assessments, and seabird and sea mammal monitoring. In total 65 indicators were scored. Lack of surveillance data led to proportional under-representation of algae, invertebrates and non-commercial fish. The overall status of coastal waters was good, with a slight worsening from 1990 and 2000 to 2010. In south-eastern Norway the pelagic biodiversity status improved following reduced nutrient inputs. The benthic status was deteriorated due to reductions in kelp, invertebrates and fish. In Mid-Norway the pelagic status deteriorated due to a strong decrease of sea-birds. The benthic status improved following a re-growth of kelp in previously sea-urchin grazed areas. Compared to terrestrial systems, the coastal waters showed better status than forests, mires and wetlands and open lowland with semi-natural grasslands and coastal heaths. The Nature Index is intended to become a permanent tool for use in Norwegian nature management and political planning and will be further developed and updated yearly.