Pro12 Champions Cup qualifying changed: No guaranteed team for each nation
Changes to qualification mean that from the end of next season, nations with teams in the Pro12 could miss out on the Champions Cup entirely.
Scotland, Ireland, Wales and Italy currently each have one Champions Cup spot guaranteed every season.
But from 2018-19 the first seven Pro12 teams will qualify on merit - and one or more nations could miss out.
Pro12 chief Martin Anayi said "these changes will deliver true meritocracy to our Championship".
Since the Italian sides joined the Pro12 in 2010, an Italian side has finished in the top seven only once in seven seasons, when Benetton Treviso came seventh in the 2012-13 season.
There is no change for the Premiership and Top 14, with the top six qualifying by right, while the 20th spot will go to the European Challenge Cup winner.
The alterations mean the qualifying process for the Champions Cup has been different every year in the five years since its inception, with the changes largely to do with how the 20th team has qualified.
BBC Radio 5 live rugby reporter Chris Jones:
Guaranteeing a representative from every country was one of the concessions made by the power brokers when the Champions Cup replaced the Heineken Cup, but this development is the final step towards a wholly meritocratic qualification process.
The weakness of the Italian teams has been a blight on the tournament up until now, while the news that the Challenge Cup winner will automatically gain entry to elite competition will also be widely welcomed.