European Policy
RBPS are part of the EU regulation for strategic plans
Article 65 of the proposal for a regulation of the European Parliament and the Council establishing rules on support for strategic plans says in number 7:
"Member States may promote and support collective schemes and result-based payments schemes to encourage farmers or other beneficiaries to deliver a significant enhancement of the quality of the environment at a larger scale or in a measurable way."
Up-to-date information on the regulation can be found under https://eur-lex.europa.eu