Title: Author(s): Document owner: Reviewed by: Workgroup: MESH action: 4 Towards high resolution habitat maps of the Southern North Sea E. Verfaillie (UGent), S. Degraer (UGent), D. Long (BGS), D. Maljers (TNO Building and Environment), K. Schelfaut (UGent), S. Van Heteren (TNO Building and Environment), W. Willems (UGent), V. Van Lancker (UGent) Els Verfaillie (els.verfaillie@ugent.be) Version: Date published: File name: Language: Number of pages: Summary: Reference/citation: Keywords: n/a MESH_ElsVerfaillie_Dublin_150307_lowres.pdf English 24 (including this page) For this exercise, the methodology of Verfaillie et al. (2006) and Degraer et al. (in press) was applied to the Southern North Sea (UK, NL, B), resulting in sedimentological maps of the median grain size and the silt-clay percentage and four habitat suitability maps of macrobenthic communities. Powerpoint presentation: 14-15 March.2007 MESH Final Conference Dublin (IRL). Towards high resolution habitat maps of the Southern North Sea E. Verfaillie, S. Degraer, D. Long, D. Maljers, K. Schelfaut, S. Van Heteren, W. Willems, V. Van Lancker Sedimentological maps, macrobenthic communities, habitat suitability modelling, Southern North Sea Bookmarks: Related information: Page 1 of 1
Towards high resolution habitat maps of the Southern North Sea Els Verfaillie 1, Steven Degraer 1, Dave Long 2, Denise Maljers 3, Kristien Schelfaut 1, Wouter Willems 1, Sytze Van Heteren 3, Vera Van Lancker 1 1 Ghent University, Belgium 2 British Geological Survey, United Kingdom 3 TNO Built Environment & Geosciences, Netherlands
Contents Aim of transnational initiative How do I make a (habitat) map? Habitat suitability maps on Belgian Continental Shelf Same exercise for Southern North Sea Reflections Validation Concluding remarks References
Aim of transnational initiative (1) Study area: Southern North Sea New maps of (median) grain size of sand fraction and silt clay percentage vs. existing Folk map: input for transnational modelling initiatives Resolution 250 m Translation of sedimentological maps into first habitat suitability maps of macrobenthic communities for S N Sea
Aim of transnational initiative (2)
How do I make a (habitat) map? (1) STEP 1: Getting the best out of the ground truth data STEP 2: Selecting and getting the best out of the coverage data STEP 3: Integration of ground truth and coverage data STEP 4: Habitat map design and layout Focus on step 2, step 3 & step 4
How do I make a (habitat) map? (2) STEP 1 STEP 2 STEP 3 STEP 4
STEP 2: Selecting and getting the best out of the coverage data (1) Selection of relevant environmental variables: sediment type (median grain size, sorting, silt clay percentage), bathymetry and derivatives, energy (waves, currents), For soft substrata grain size and silt clay percentage seem to be the most relevant, but other variables have to be examined (e.g. d10, d90, dx, bathymetric derivatives such as BPI)
STEP 2 (2) If point data -> full coverage map of relevant environmental variables by interpolation Some variables are full coverage already e.g. multibeam bathymetry or backscatter, side scan sonar, satellite imagery
STEP 2 (3) Example of geostatistical interpolation of Ds50: Kriging with an external drift (KED) using bathymetry as secondary information R² (bathymetry Ds50) for Belgian and Dutch Continental Shelf up to IJmuiden: 800 R 2 = 0.3681 700 600 D50-sand (micron) 500 400 300 200 100 0 0 5 10 15 20 25 30 35 40 45 50 Bathymetry (m)
STEP 2 (4) KED vs Ordinary Kriging (OK): clear difference in depth defined zones e.g. sandbanksswales Verfaillie et al. (2006) Northing (m) 5660000 5680000 5700000 5720000 5740000 460000 480000 500000 520000 OK Easting (m) KED: median grain size (mu) 0-100 100-200 200-250 250-300 300-350 350-400 400-500 500-600 0 2.5 5 10 km UTM31N - WGS84 coordinates
STEP 2 (5) STEP 2 (5) Silt clay % Ds50
STEP 3: Integration of ground truth and coverage data (1) macrobenthic communities (Van Hoey et al., 2004): Macoma balthica community Increasing (median) grain-size Abra alba community Nephtys cirrosa community Ophelia limacina community Increasing silt-clay% HABITAT model (Degraer et al., in prep.) Quantification relation macrobenthos versus silt-clay% and median grain-size Multiple Discriminant Function Analysis Community dependent accuracy 67 88 %, average 77 %
STEP 3 (2) Silt-clay% Application of HABITAT model Median grain-size
STEP 4: Habitat map design and layout Habitat suitability maps of 4 macrobenthic communities
STEP 4: Habitat map design and layout Translation of habitat suitability maps into EUNIS level 5 map
Same exercise for Southern North Sea (1) Silt-clay% Application of HABITAT model Ds50
Same exercise for Southern North Sea (2) FIRST TRIAL VERSION!
Reflections on first trial of habitat suitability map of macrobenthic communities in soft substrata in the Southern North Sea: Southern N Sea same biogeographical area with comparable sediment type and communities Shading areas out of limits of model Gravel? As gravel is not an input for the model, typical associated fauna will not be predicted! High suitability of Abra alba community around shading areas are modelling artefacts Trans-border modelling work not evident! Different resolution of input data Different sampling methods and processing Absence of Macoma balthica community around Western Scheldt estuary Lower estimation of Dutch silt clay percentages?
Validation of coverages OK KED: best results for all validation indices! Verfaillie et al. (2006) Until now: only validation for Belgian dataset!
Validation of Habitat model Three-fold cross validation of the empirical habitat suitability model using both median grain size and silt clay percentage a posteriori average CCI (i.e. correctly classified instances) of 77% (communitydependent CCI ranging from 67 to 88%) and a Cohen s kappa of 0.67, pointing towards a high accuracy of the model Only done for Belgian dataset!
Concluding remarks Folk map (qualitative classes) vs Ds50 map and silt clay map (quantitative data): more useful as model input Examination of other model inputs relevant for biological communities/species e.g. gravel, Dx, bathymetric derived maps Interesting first results of habitat suitability maps of Southern North Sea Community vs species specific modelling (e.g. Willems et al., in press) Trans-border work remains difficult!
References Degraer, S., E. Verfaillie, W. Willems, E. Adriaens, V. Van Lancker & M. Vincx (in prep.) Habitat suitability as a mapping tool for macrobenthic communities: An example from the Belgian part of the North Sea. Van Hoey, G., Degraer, S., Vincx, M., 2004. Macrobenthic community structure of soft-bottom sediments at the Belgian Continental Shelf. Estuarine, Coastal and Shelf Science 59, 599 613. Verfaillie, E., Van Meirvenne, M. & Van Lancker, V., 2006. Multivariate geostatistics for the predictive modelling of the surficial sand distribution in shelf seas, Continental Shelf Research, 26 (19), 2454-2468. Willems, W., Goethals, P., Van den Eynde, D., Van Hoey, G., Van Lancker, V., Verfaillie, E., Vincx, M., Degraer, S. (in press). Where is the worm? Predictive modelling of the habitat preferences of the tube-building polychaete Lanice conchilega (Pallas, 1766). Ecological Modelling.
Thank you! Joint Nature Conservation Committee (JNCC) www.jncc.gov.uk Ghent University www.ugent.be Ifremer www.ifremer.fr/rebent Centre for Environment, Fisheries and Aquaculture Science (CEFAS) www.cefas.co.uk Agri-Food and Biosciences Institute www.afbini.gov.uk Natural England www.naturalengland.org.uk WAGENINGEN IMARES Marine Institute www.marine.ie IMARES www.wageningenimares.wur.nl Envision Mapping Ltd www.envision.uk.com Amgueddfa Cymru National Museum of Wales www.museumwales.ac.uk/en/biosyb/ TNO Netherlands Organisation for Applied Scientific Research www.tno.nl British Geological Survey (BGS) www.bgs.ac.uk NEW ENO INTERREG IIIB North West Europe www.nweurope.org