Habitat maps are important as they contain essential information about the seafloor which is required to sustainably manage and develop the economic potential of European sea-basins. European seabed habitat maps serve many purposes including the design of ecologically coherent Marine Protected Area (MPA) networks, species distribution modelling, establishing monitoring programmes for seabed habitats and informing maritime spatial planning (MSP). They are also indispensable for Member States to fulfill their legal obligations under the Marine Strategy Framework Directive (MSFD), where full coverage of seabed predominant habitats of all European seas is required.
Unfortunately, habitat maps from surveys are very costly and time consuming to produce. A more time- and cost-efficient way to meet the need for a full coverage habitat map is to use low resolution maps and models to 'predict' seafloor habitat types. These maps of expected seabed-habitat types can be generated by combining a series of proxy measurements such as; water depth, sediment type and light levels amongst others, using statistical analysis and Geographical Information System (GIS) modelling.
Objectives of EMODnet Seabed Habitats
The primary objective of Seabed Habitats in Phase II is to create a homogeneous seabed habitat map covering all European seas that will be freely available to users and will effectively meet their needs but also to trigger the collation of maps from surveys throughout Europe and their dissemination through the internet for wider use.
Key services provided by EMODnet Seabed Habitats
EMODnet Seabed Habitats provides the following key services to users:
- Map Viewer: a free, interactive mapping portal (webGIS) for viewing and downloading broad-scale, seabed habitat maps as well as secondary input data layers such as energy and light penetration at the seabed. Users can build a query based on specific criteria such as geographic area, data layer or specific habitat. Alternatively users can simply browse for information using the icons provided.
- Downloading: all layers can be exported using the Web Map Service (WMS) to personal desktop GIS applications or to other web mapping portals. Information can also be downloaded as ready-to-use maps, in pdf format or in GIS format to be easily overlaid with users’ datasets.
- Search: fully searchable metadata describing the file content is provided with the files following INSPIRE directive standards.
EMODnet Seabed Habitats will expand Phase I EUSeaMap work to cover the remaining sea-basins by mobilising data capture from various sources. The first step is to acquire the best-available spatial data for several environmental variables. The data are organised and harmonised into raster images divided into classes. These data can be combined by ‘layering’ the data in GIS to create a combined output describing the habitat. The principal input layers are the type of seabed substrate and the biological zones. Depending on the basin, layers of hydrodynamic energy levels, salinity and/or temperature are also produced. For example the hydrodynamic energy layer at the seabed is divided into ‘Low’, ‘Medium’ and ‘High’ classes as per EUNIS requirements.
Data sources primarily include data provided by EMODnet Geology and Bathymetry projects. List of data sources prior to EMODnet layers include:
- IBCM map (substrate)
- GEBCO data (bathymetry)
- Wind and wave data from MyOcean, ECMWF, IOWAGA
- Light attenuation in water from the EU MERIS satellite
EMODnet Seabed Habitats product development
- Harmonised broad-scale habitat map: A single harmonised broad-scale habitat map is currently available for the Baltic Sea, the Western Mediterranean Sea, the Greater North Sea and the Celtic Seas, SW Atlantic and Macaronesia (Figure 1). Its coverage is being extended to all European seas by 2016. The habitats in this map are consistent between basins and approximately correspond to the MSFD ‘predominant habitats’. This map is available to end users at 250m resolution (roughly the 1:1M scale, see an example in Figure 10).
- Region-specific maps: Although there is a need to produce a harmonised map across the regions, harmonising necessarily loses some of the region-specific data. More detailed maps are possible, owing to the specific conditions relevant to each region. The project will assess the feasibility of locally producing higher resolution. Typically coverage of between 10-20% would be obtained if a scale of 1:250000 was contemplated.
- Confidence maps: Combining the data in a meaningful way for the purpose of predictive mapping is a complex process, given that there is variation in the thematic and spatial scale of input data layers and the reliability of threshold values of environmental parameters in producing biologically relevant boundaries. This makes the provision of confidence assessment all the more relevant. The confidence score reflects the level of confidence users can expect in broad-scale maps. Likewise maps from surveys are delivered along with a confidence score based on their metadata which informs users on their level of quality.
Improvements in the current development Phase II
The calibration of the EUNIS thresholds in newly added basins (such as the Eastern Mediterranean and the Black Sea) using biological data is the most innovative strand of work during EMODnet Phase II (2013-2016). Following consensus within the seabed mapping community for the EUNIS classification categories, it is then a matter of translating these boundaries into physical amounts. With the advent of physical models running over long time periods, statistics can now be computed and climate established for a number of physical parameters (temperature, waves and currents, salinity, light etc.) with full coverage for European seas.