Tex. Parks & Wild. Code § 81.504

Inclusion of a state or local park, preserve, wildlife refuge, or other area within the system established under this subchapter does not cancel, supersede, or interfere with any other law or provision of an instrument relating to the use, management, or development of the area for other purposes except that any agency administering an area within the system is responsible for preserving the natural character of the area under the policies of the commission.