Iowa Code § 481A.6: Game management area.

The commission may establish a game management area upon any public lands or waters, or with the consent of the owner upon any private lands or waters, when necessary to maintain a biological balance as provided in section 481A.39 or to provide for public hunting, fishing, or trapping in conformity with sound wildlife management. When a game management area is established, the commission shall with the consent of the owner, if any, have the right to post and prohibit, and to regulate or limit the lands or waters against trespassing, hunting, fishing, or trapping. Any violation of the regulations is unlawful.