If for some reason the riding association ceases to exist, it would go on to the party, and all those responsibilities would be moved on to the party as well. As for a riding association, most parties go through some type of nomination process, some type of agreement on the candidate, so there's some buy-in from the riding association.
Pour ce qui est de l'association de circonscription, la plupart des partis ont une espèce de processus de mise en candidature, une entente avec le candidat, alors l'association l'endosse.