BfR-Wissenschaft 
25 
Thus, for oil spill response and precaution measures, a sensitivity study of the entire intertidal 
area was badly needed in order to assess the potential to minimize ecological and economi 
cal damage. Based on comprehensive field surveys (i.a. Dorjes et al. 1984, Farke et al. 
1985, van Bernem et al. 1989) and in close cooperation with the Central Command for Mari 
time Emergencies (Havariekommando - HK), an automated expert-model for the German 
part of “Wadden Sea” areas was developed at the Institute for Coastal Research (Helmholtz- 
Zentrum Geesthacht, HZG) (Schiller et.al 2005, van Bernem et. al 2007). As an operational 
model it serves as important instrument for decision making processes, precautionary 
measures and the further design of oil spill response strategies. 
Sheltered tidal flats, salt marshes and adjacent estuaries belong to the types of coast which 
are most sensitive to oil pollution. Since it is not possible to protect the entire German North 
Sea coast equally at all levels, oil spill contingency planning requires a more detailed classifi 
cation. For this reason, individual soft bottom habitats, communities and stocks of salt 
marshes, macrofauna, waterfowl and estuarine biotope types were evaluated and classified 
according to their vulnerability to oil pollution. 
The sensitivity of a particular area to oil contamination depends largely upon the physical 
characteristics of the habitat, the susceptibilities of individual species and their ecological 
properties within the communities. Flence, the field work for habitat mapping during 2003- 
2006 was a central part of the study. For this part, the experiences and results obtained from 
the previous FIZG-project “Thematic Mapping and Sensitivity Study of Intertidal Flats” during 
the years 1987-1992 served as a valuable basis. For example, the documentation of chang 
es during these periods of observation provides information on stability features of the eco 
systems involved. During the first project nearly 5000 locations were processed and charac 
terized using about 70 parameters for each site. The in-situ mapping was a combination of 
estimated and measured values, collected along a grid net of locations with 1 km interval. 
The estimated values, including biotic and abiotic parameters, were documented using a 
standardized protocol („record sheet“). They comprised, for example, information on the 
presence of micro- and macroalgae, surface structure (i.e. ripple, colour) and sediment char 
acteristics. The measured values included grain size, shear strength, water content of sedi 
ments as well as the macrofauna species present. 
The assessment of value of each location was calculated using an automated expert system 
developed at FIZG and based on neural network techniques and advanced classification 
methods (tree fit). Four classes have been defined to scale the oil sensitivity of tidal flat areas 
from low (1: green) to high (4: magenta). The design of this model enables the „Central 
Command for Maritime Emergencies“, as the main-user to calculate the spatio-temporal sen 
sitivity of intertidal areas without extensive further expert assistance. 
The spatial distribution of the sensitivity of tidal flat areas (benthic index) was combined with 
data on saltmarsh distribution and the presence of sea grass and mussel beds. These addi 
tional data were integrated using the monitoring results of the national park authorities of 
Lower Saxony, Schleswig-Flolstein and Flamburg. The temporal aspect of this sensitivity was 
calculated using the monitoring data of breeding and migratory birds which are compiled 
yearly by these authorities. The complete data sets were used together with a geographic 
information system (GIS) to generate sensitivity maps of the German North Sea Coast (Fig 
ure 5.1).