Marine seabed habitats are highly influenced by the geophysical variables they feature. These are firstly seabed type, topography and exposure, but in the more inshore areas also include water transparency, salinity, temperature etc. Some relations have been established in a top-down approach between adequate combinations of these variables and the higher levels of the Eunis (European Nature Information System) habitat classification which is currently being used to harmonise seabed habitat mapping throughout Europe. These levels have been referred to as "Marine landscapes", as they are aggregations of a number of lower Eunis habitats from levels 4 to 6. More elaborate variables that are thought to have a bearing on habitat types can be computed from the initial basic ones through comprehensive use of GIS functions. The depth provides slope and orientation. An aggregation of currents and wave action on the seabed provides exposure. Sediment grain size along with currents and slopes allow bedforms on sedimentary bottoms to be predicted. Adequate binning of these quantities and their cross-tabulation leads to a number of landscape types which usually pertain to level 3, but also 4 at times. That raises the question: to which extent could assimilating of biological samples (by way of, e.g., a point–to-polygon method) allow a holistic habitat map at a lower typology level to be produced?
The notion of marine landscape can be further exploited to describe any particular habitat, provided that the distribution laws of this habitat with respect to the geophysical parameters are established on the basis of adequate field data sets. This is a bottom-up approach of habitat modelling adapted to mapping individual priority habitats for which field samples are available.
Populus Jacques, Hamdi Anouar, Golding Neil, Van Lancker Vera, de Oliveira Eric (2006). Towards prediction of seabed habitats. Actes du colloque CoastGIS'06, Australia, July 2006. https://archimer.ifremer.fr/doc/00000/6338/