525 ILCS 30/14
Nature preserves are held in trust, for those uses and purposes expressed in this Act which are not prohibited by their instruments of dedication, for the benefit of the people of the State of present and future generations. Areas dedicated as nature preserves are hereby declared to be put to their highest, best and most important use for the public benefit. They shall be protected, managed and used in the manner provided by rules. They may not be taken under power of eminent domain or by other means for any other use except another public use and except upon approval of the Commission, the Governor and any public owner of a dedicated interest therein after a finding by the Commission of the existence of an imperative and unavoidable public necessity for such other public use, and upon such terms and conditions as the Commission may determine, except as may otherwise be provided in the instrument of dedication.
The owner of an interest or right in a nature preserve may amend the instrument of dedication, with the approval of the Commission and the Governor, after the Commission has determined that the amendment will not permit an impairment, disturbance, development or use of the nature preserve or the natural features therein in a manner inconsistent with the purposes of this Act.
Before the Commission may make a finding of the existence of an imperative and unavoidable public necessity for another public use, grant or dispose of a nature preserve, grant a license, easement or other interest or right therein or amend any instrument of dedication, it shall, in a manner to be provided by rules, give public notice of the proposed action and provide an opportunity for any person to be heard at a public meeting or to request the holding of a public meeting.
The Commission may cause any legal instrument altering the status of a nature preserve to be filed for record in the office of the recorder for each county in which the nature preserve is located.
525 ILCS 30/14