Recent research has highlighted strong correlations between soil edaphic parameters and bacterial
biodiversity. Here we seek to explore these relationships across the European Union member states with
respect to mapping bacterial biodiversity at the continental scale. As part of the EU FP7 EcoFINDERs
project, bacterial communities from 76 soil samples taken across Europe were assessed from eleven
countries encompassing Arctic to Southern Mediterranean climes, representing a diverse range of soil
types and land uses (grassland, forest and arable land). We found predictable relationships between
community biodiversity (ordination site scores) and land use factors as well as soil properties such as pH.
Based on the modelled relationship between soil pH and bacterial biodiversity found for the surveyed
soils, we were able to predict biodiversity in
1000 soils for which soil pH data had been collected as part
of national scale monitoring. We then performed interpolative mapping utilising existing EU wide soil pH
data to present the
first map of bacterial biodiversity across the EU member states. The predictive
accuracy of the map was assessed again using the national scale data, but this time contrasting the EU
wide spatial predictions with point data on bacterial communities. Generally the maps were useful at
predicting broad extremes of biodiversity reflective of low or high pH soils, though predictive accuracy
was limited for Britain particularly for organic/acidic soil communities. Spatial accuracy could however
be increased by utilising published maps of soil pH calculated using geostatistical approaches at both
global and national scales. These
findings will contribute to wider efforts to predict and understand the
spatial distribution of soil biodiversity at global scales. Further work should focus on enhancing the
predictive power of such maps, by harmonising global datasets on soil conditioning parameters, soil
properties and biodiversity; and the continued efforts to advance the geostatistical modelling of specific
components of soil biodiversity at local to global scales.