Each district established pursuant to sections 67.5000 to 67.5033^* shall be responsible for the planning, development, operation, and maintenance of a public system of interconnecting trails, open spaces, greenways, and parks throughout the county comprising such district, except as otherwise specifically provided for by statute. The powers and responsibilities of the district shall be supplemental to, but shall not be a substitute for, the powers and responsibilities of other parks and recreation systems located within the district or for the powers of other conservation and environmental regulatory agencies. Nothing in this section shall be interpreted to give any district the authority to regulate water quality, watershed, or land use issues in the county comprising the district.