There's a part of them, for sure, but more on the other winter sports, like ski.
At the olympics, almost half of all the italian athletes were from Trentino-Alto Adige/Südtirol.
About skating, the rinks are mostly on the nord, but the major schools are spread between the northern regions. There's also roller skating, Italy is competitive on that, so sometimes that can get some athletes, like Guarise, to switch to ice after some major result on the rollers.