SMITHTOWN - A Suffolk lawmaker has proposed a change to the county's Open Space Preservation plan that she says will help protect the environment, but the bill has galvanized lots of local environmentalists who say it will do just the opposite. The open-space program is designed to help the county acquire and protect undeveloped land. Leg. Kara Hahn (D-Setauket) has proposed a bill that would enact a 90-day hold on future open-space acquisitions. Hahn says there's so little money left in the fund that a wait period will give the county time to prioritize and acquire the most environmentally sensitive areas first. Dozens of environmentalists are arguing that a 90-day delay could jeopardize important acquisitions. Some say they worry that the bill is a first step toward killing the open-space program entirely.