New EMODnet biology data product: Presence/absence of macrobenthos in European Seas
When mapping taxon distribution, it is important to know where the taxon did and did not occur. Inferring absences from presence-only databases is difficult and always involves some guesswork. In this product we have used as much meta-information as possible to guide us in inferring absences.
Datasets can contain implicit information on absences when they have uniformly searched for the same taxon over a number of sample locations. Normally, if the taxon would have been present there, it would have been recorded. Other datasets, however, are not informative about absences (e.g., museum collections). They were not used in the present collation.
In this product, it was implicitly assumed that a dataset inventorying the endomacrobenthos, was targeting all taxa belonging to this functional group, a distinction that can usually be made on the basis of the metadata.
At the taxon level, taxonomic registers such as WoRMS (WoRMS Editorial Board, 2021) give information on the functional group the taxon belongs to, which is present for many taxa. We used this information to select for benthic species but completed it with additional steps based on taxonomy and coherence of the datasets. Endomacrobenthos is a functional group often studied in the framework of monitoring projects. In total, this dataset contains information on presence/absence of almost 10,000 taxa in over 200,000 locations. It summarizes many person-years of efforts in monitoring and study of the benthos and is ready for many types of exploration of the patterns of occurrence of these species in space and time. Unfortunately, and despite the enormous effort represented, coverage of the European waters is not homogeneous. The dataset should therefore also be used to delineate areas where additional efforts in collection and assemblage of datasets would be most profitable.