He once ran the huge and important National Park on the border of Canada in Montana, Glacier National Park, for 8 years. Now Gil Lusk is retired and lives in Quail Creek, near Green Valley. Lusk was the club's speaker January 14, 2020 and talked about his career with NPS and the role of Rotary in America's National Parks.
Lusk said Rotary's National Parks involvement began nearly 90 years ago with the establishment of a "Peace Park" on the border of the U.S. and Canada which sits atop Glacier N.P. Rotary International, he said, established there the world's first 'peace park' which emphasized one of Rotary's basic tenants---world peace. 
Rotary then became involved in other projects with the NPS, including one in which he was involved, in the Big Bend NP of Texas, which borders Mexico. A new Peace Park will be established there in conjunction with a neighboring Mexican park, hopefully by 2025. 
Lusk is also a historian and has chronicled the challenges and problems of the National Parks in a book he has written, "National Parks – Our Living National Treasures, A Time for Concern". It is well worth the read and he is well worth listening to if you get the chance.