BILLINGS, Mont. — Wildlife advocates and a Montana Indian tribe have asked a U.S. court to restore protections for grizzly bears in and around Yellowstone National Park so that trophy hunting of the animals would not be allowed. The Northern Cheyenne Tribe, the Humane Society and several conservation groups filed three lawsuits Tuesday and Wednesday in federal court in Montana, challenging the government’s recent move to lift protections. Idaho, Montana and Wyoming are planning limited public hunting of the region’s roughly 700 bears, although no hunts are expected this year. Critics say there is already too much pressure on the bear population as climate change affects what they eat and as conflicts with humans result in dozens killed annually. A separate challenge of the government’s decision was filed in July by Native Americans from seven states and Canada.