What the view shows
Reading the combined distribution of cattle density and NVZs.
The overlap shows which territories combine higher cattle density with Nitrate Vulnerable Zones, areas designated under Directive 91/676/EEC in which specific water-protection measures apply. The co-presence of the two variables does not allow responsibility to be attributed, nor a causal relationship to be demonstrated.
The overlap does not cover six regions: Bolzano and Aosta Valley, where no NVZ has been designated, and Marche, Molise, Basilicata and Calabria, whose designated NVZs are not yet integrated into the view. These territories account for 12.8% of national cattle farms (695 of 4,673 municipalities). For these regions the map therefore does not allow an assessment of the co-presence of the two variables.
The weight of the overlap
Share of municipalities in NVZ area compared with the share of animals those municipalities concentrate.
Municipalities in NVZ areas are only 17.4% of the national total (1,053 of 6,037 municipalities with direct BDN data), but they concentrate a much higher share of animals. The chart below shows by how much, species by species.
How to read it: the empty dot marks the share of municipalities in NVZ, the 17.4% seen above, the same on all three rows because it's the same reference point. The filled dot marks the share of that species' animals found in those same municipalities. The line joining them measures the distance between the two shares: the longer it is, the more that species is concentrated in NVZ area relative to the weight, in number of municipalities, that area represents nationally.
In municipalities classified as NVZ, the share of Cattle is 2.5 times the share represented by these municipalities in the total considered; the ratio is 3.4 for Pigs and 2.4 for all species combined. The data thus points to an above-average concentration of animals in the municipalities included in the view and classified as NVZ.
Municipalities with direct BDN data (excluding those masked by the anonymisation threshold, reattributed only at province level); inside/outside NVZ classification based on the municipality's point location, not its real boundary. NVZs not yet integrated for Marche, Molise, Basilicata, Calabria, Bolzano and Aosta Valley.