To amend the Sikes Act to make certain improvements to the administration of cooperative agreements for land management related to Department of Defense readiness activities, and for other purposes.

Amends the Sikes Act (conservation programs on federal lands) to allow funds appropriated to the Department of Defense (DOD) that are obligated to cooperative agreements with states, local governments, Indian tribes, nongovernmental organizations, and individuals for maintenance and improvement of natural resources located off of military or state-owned National Guard installations (but that are related to current or anticipated military activities) to be:

• paid in a lump sum and include an amount intended to cover the future costs of the activities under the agreement;
• invested by the recipient in accordance with the recipient's own investment management guidelines, with any investment interest or income permitted to be applied for the same purposes as the principal; and
• used only for the direct costs of maintaining and improving the natural resources pursuant to an approved DOD Integrated Natural Resource Management Plan and for certain indirect and administrative costs that do not exceed 10% of the total cost of the project.

Allows such cooperative agreements to be used to acquire property or services for the direct benefit or use of the U.S. government.

Prohibits amounts available to DOD from being used under such Act to acquire fee title interest in real property for such natural resources projects that are not on a military installation.

Requires the Inspector General of DOD to: (1) conduct an audit of the natural resources projects funded with amounts available to DOD under the Sikes Act that are not on a military installation, and (2) report to Congress on the audit by October 1, 2018.

Terminates this Act on October 1, 2019, except that any cooperative agreement entered into under this Act on or before September 30, 2019, shall continue.