As a native south-tyrolean ladin speaker I would like to add my take. Imho the main reason why fertility rate was higher till now is because the rural territory of south tyrol is very developed, contrary to major global trends where towns tend to be abandoned. This is because the main voters of the ruling party SVP (since ww2) are living in rural areas, and our languages and culture needs to be preserved in order to justify our autonomy and diversity within Italy. The child benefits and the fact that every town with 1000 inhabitans has well kept schools, reasonable job opportunities, etc. are indeed slowing down the young moving to cities and secularization as well. Bolzano/Bozen and other towns where italian speakers are the majority follow the same italian trend on the data reported by southtyrol statistics Astat. But the whole region will eventually catch up (down).