A wildlife habitat bond fund is created in the state treasury. At the direction of the commission as provided in the bond proceedings or pursuant to section 483A.52, subsection 1 or 2, and as certified by the director, the treasurer of state shall credit to the wildlife habitat bond fund from the revenues received from the sale of wildlife habitat stamps a sum at least sufficient to pay interest on the bonds in each fiscal year and principal on the bonds that mature during each fiscal year. In each fiscal year after July 1, 1986, and after bonds are issued, and until all the bonds issued have been retired, in order to provide for the payment of principal of the bonds issued and sold and the interest on them as the same become due and mature, there is pledged and annually appropriated out of the revenues to be credited to the wildlife habitat bond fund an amount sufficient to pay principal and interest on the bonds issued for each of the years the bonds are outstanding. The director shall annually certify to the treasurer the amount of funds required to pay interest on the bonds in the ensuing fiscal year and the principal on the bonds that mature during the ensuing fiscal year.