Sardinian warbler is one of the 15 species that were included in the third data provision and for which pilot maps were produced recently. In addition to the four pilot maps (breeding occurrence, breeding code, abundance code and changes in comparison to EBBA1) that were created for this species on a 50×50 scale, a new milestone was made in the case of Sardinian warbler – the first fine resolution map (10×10 km).
EBBA2 attempts to show information on species distribution at 10×10 km, which could be considered a fine resolution at European scale. It would be too ambitious to cover the whole of Europe in a 10×10 km grid but with a sampling approach modelling maps at such a resolution should be possible for many species. These fine-grained maps are based on statistical models that allow inference on the species occurrence in non-surveyed squares thanks to the knowledge about the patterns of species occurrence in a number of surveyed areas. The generation of these maps represents a new challenge at European level and they are expected to be a source of information of great interest for science and conservation. Fine-grained maps show the probability of occurrence of a species. It is important to stress that as well as resolution and statistical inference, these maps differ conceptually from the others since they consider species occurrence during the breeding season, not taking into account breeding evidence (confirmed, probable, possible) or absolute abundance. However, it is important to outline that measures of occurrence shown in these maps can often be considered as a surrogate of the relative abundance of the species.
The first pilot EBBA2 high resolution map (10×10 km) for the Sardinian Warbler (Sylvia melanocephala) was produced using the preliminary set of standardised data provided by national coordinators and ensemble prediction of seven species distribution models (ANN, BRT, FDA, MARS, RF, GAM and GLM). This first modelled pilot map shows a few inconsistencies with our current knowledge of the species distribution and will be improved with the final data.
Probability of occurrence of Sardinian warbler, high resolution map (10×10 km)
Preliminary occurrence map for Sardinian warbler (50×50 km)
Sergi Herrando and Pietro Milanesi, 1.3.2017