Publication Abstract

Using the EUNIS habitat classification system in broadscale regional mapping: some problems and potential solutions from case studies in the English Channel.

Using the EUNIS habitat classification system in broadscale regional mapping: some problems and potential solutions from case studies in the English Channel.

Roger Coggan, Ceri James, Bryony Pearce and Jennifer Plim

The EUNIS habitat classification system provides a standard for recording European marine habitats and biotopes. Its hierarchical structure introduces physical, environmental and biological parameters at different levels, making it attractive for use in broadscale predictive mapping. We have developed a modelled EUNIS map for an area of 12,755 sq km in the eastern English Channel, but in doing so met two difficulties which stem from the structure of the EUNIS classification system. Firstly, it includes only two major substrate classes, ‘rock’ and ‘sediment’, so provides no solution for areas where rock is covered by a thin (<1.0 m) sediment layer. Acoustic surveys indicate such areas as rock but grab surveys show them as sediment, and the communities they support can be distinct from those in pure rock or sediment habitats. Secondly, there is an inconsistency in the level at which EUNIS introduces biological zones into the hierarchy. For rock habitats the littoral, infralittoral and circalittoral zones are introduced at EUNIS level 2, but the deep circalittoral only at level 4. For sediment habitats, level 2 only differentiates littoral from sublittoral; the infralittoral, circalittoral and deep circalittoral zones are all introduced at level 4. As a result, broadscale maps classified at EUNIS levels 2 or 3 are internally inconsistent, showing some but not all sublittoral zonation for rock habitats and no sublittoral zonation for sediment habitats. This can be greatly misleading to the end-user of the maps. Our case study offers solutions to these problems by making some modifications to the EUNIS system, introducing a new substrate class of ‘rock and thin sediment’ and allowing biological zones to be represented more equitably.

Reference:

R. Coggan*, C. James, B. Pearce and J. Plim (2011) Using the EUNIS habitat classification system in broadscale regional mapping: some problems and potential solutions from case studies in the English Channel. ICES CM 2011/G3. ICES Annual Science Conference 2011. Theme Session G: Habitat Modelling and Mapping for better assessment and monitoring of our seas.

R. Coggan*, C. James, B. Pearce and J. Plim

ICES CM 2011/G3. ICES Annual Science Conference 2011. Theme Session G: Habitat Modelling and Mapping for better assessment and monitoring of our seas.