Three-quarters of the seats on the U.S. National Park Service advisory board are vacant following a mass resignation Monday night, citing Interior Secretary Ryan Zinke's unwillingness to meet with them.Nine of the panel's 12 members, led by former Alaska Gov. Tony Knowles, handed in their resignations. The bipartisan panel was appointed by President Obama and the terms of all members who quit were set to expire in May.Knowles, in a letter of resignation from himself and the eight other members to Zinke, said the board had "worked closely and productively through 2016 with dedicated National Park Service employees, an inspiring Director and a fully supportive Department."Since then, as explained in the letter, the board had repeatedly tried and failed to secure a meeting with the new interior secretary."[Our] requests to engage have been ignored and the matters on which we wanted to brief the new Department team are clearly not part of the agenda," the letter reads.Alaska Public Radio quoted Knowles as saying that the Department of the Interior "showed no interest in learning about or continuing to use the forward-thinking agenda of science, the effect of climate change, protections of the ecosystems, education.""And it has rescinded NPS regulations of resource stewardship concerning those very things: biodiversity loss, pollution and climate change," he added.According to The Washington Post: