Yosemite is asking hikers to stop building those Instagram-worthy rock cairns—and it’s not just about keeping the trails pretty. Rangers say these stacks actually mess with tiny critters and plants living under the rocks, and can even speed up erosion. Only official cairns should mark trails; the rest can confuse hikers and harm the ecosystem. Next time you’re out there, leave the rocks as you find them and help keep Yosemite wild for everyone (and everything) that calls it home. What do you think—should parks crack down on this more? #News #Yosemite #LeaveNoTrace