The U.S. National Park Service should stop worrying so much about pleasing visitors and instead focus on protecting natural resources, says an advisory panel. In its report, which is slated to be made public tomorrow, the National Park System Advisory Board says that the agency should “[a]dopt the conservation of biodiversity as a core principle” and reduce the environmental impact of its operations. The panel’s recommendations clash with the Bush administration’s parks plan, which emphasizes improving the experience of visitors by fixing crumbling roads and faulty sewer systems, and constructing new visitor facilities.