No statute amending or repealing, or adding to, the provisions of Part 4.5 (commencing with Section 12200) of Division 6 of the Water Code (the Delta Protection Act) shall become effective unless approved by the electors in the same manner as statutes amending initiative statutes are approved; except that the Legislature may, by statute passed in each house by roll call vote entered in the journal, two-thirds of the membership concurring, amend or repeal, or add to, these provisions if the statute does not in any manner reduce the protection of the delta or fish and wildlife.