The U.S. National Wildlife Refuge System could get a $56.5 million budget increase in the next fiscal year, according to an announcement made yesterday by Interior Secretary Gale Norton. The proposed increase would represent an 18 percent budget hike and would be earmarked for maintenance and renovation of such features as boardwalks, trails, and levies. Although it would be the largest budget increase in seven years, critics say it is not sufficient to address the $600 million backlog of maintenance projects at the nation’s 538 wildlife refuges. Norton, who has been controversial and unceasing in her efforts to open the Arctic National Wildlife Refuge to oil drilling, emphasized the importance of keeping refuges up-to-date: “You need to have more trails so people won’t wander off into the habitat,” the secretary said.