A measure that Oakland, Calif., voters approved to fund the local zoo with a flat property tax will stand after a taxpayer watchdog group failed to convince the California Supreme Court to review the initiative.

In March, the California Court of Appeal, First Appellate District, struck down a portion of the ballot initiative’s language for violating a state constitutional provision that bars conferring specific organizations with certain privileges, but upheld the remainder of the measure.

The California Supreme Court’s Wednesday order halts the Alameda County Taxpayers’ Association Inc.’s opposition to the voter initiative, which imposed a $68 annual parcel tax …