76-12-107. Methods of bringing land under part. A natural area, as defined in 76-12-104, may become subject to the provisions of this part in any of the following ways:

(1) designation by the board on lands controlled by the board;

(2) designation by the legislature on lands owned by the state of Montana;

(3) acquisition by the board by purchase with consent of the property owner of sufficient interests in private property to protect the natural area; provided, however, that transfer of surface property or development rights shall not alter the rights attending the subsurface estate if owned by another party;

(4) gift accepted by the board under the authority of 77-1-213, including conservation easements, provided that lands accepted must be protected and managed as natural areas and money accepted must be used in accordance with the purposes of this part;

(5) trade of state-owned trust land for a natural area on federal, county, or private land, provided, however, that lands received in exchange for trust lands should be equal in value to the exchanged trust land and as closely as possible equal in area; or

(6) registration of land by the department, following appropriate documentation and owner consent, that has been designated, dedicated, or otherwise protected as a natural area by the owner, including a private landowner, public interest group, or other land management agency.