Immediately upon the filing of the certificate in the office of the Secretary of State and in the office of the county clerk, the members of the board of directors named in the petition, or appointed by the Governor in case the district has within its boundaries twenty-five or more cities and villages, shall qualify as provided for in section 70-616 and immediately assume the duties of their office. Failure or refusal to qualify shall be deemed to create a vacancy, which shall be filled as provided in section 70-615. The first meeting of the board of directors shall be called by the director first named in the petition who qualifies.