As blogger Ivan Vladimirov noted, and as the above map confirms, Putin has become the President of ethnic Russians. This stands to reason. For instance, it’s probably hard for many Dagestanis to see the appeal of Crimea. As opposed to, say, for the peoples of the Kuban.
Tatarstan also delivered a pretty low result, possibly over Tatar sullenness about Putin recently l ifting the mandatory teaching of the Tatar language there, which was a source of ire for that region’s non-Tatar minorities.