Marine landscape maps: methodology and potential use

The Marine Landscape is a concept that originated in Canada (Roff and Taylor 2000) and was recently implemented in UK and Europe in the respective frames of the UKSeaMap (Connor 2006) and Mesh projects. It aims to describe the marine environment with respect to its main geophysical features, in terms of both the seabed and water column. Marine landscape maps are not a surrogate for genuine habitat maps which are produced by incorporating biological data from samples to the physical map. They provide a more global vision of our coastal and shelf environment in terms of their main physiographic traits and hence act as a support for national/regional policy and spatial planning. While initially applied on a more global scale (resolution of one nautical mile), the concept was taken forward and applied to the French coastal approaches where digital data sets were available at higher density. The classification used for a landscape map is quite flexible. It will not be the same in a full sedimentary type of seabed or a rocky foreshore and differs in fully marine or in more continental seas such as the Baltic, for example. It needs to be adapted on a case-by-case basis to the local physiography and also to be discussed with the main stakeholders to best serve their needs. The paper discusses the methodology used to produce a seabed map, mainly relying on data cross-tabulations within a GIS, and deals with both raster and vector data. Validation against historic habitat maps is presented. Problems linked to discrepancies in data resolution are also discussed. Finally an application making use of the landscape map for conservation issues in Brittany is discussed