Sacramento, CA — Critics of a new version of the national parks guidelines say it wrongly tilts the balance from preservation to recreation.

The National Park Conservation Association says the plan opens the door to snowmobile rides, mountain biking and other activities that might impact wildlife and the silence of the backcountry.

Park service officials say the new plan still has the mission laid out in the 1916 act that created national parks to conserve the scenery and the wildlife. There are less than two weeks left in the 90-day public period.