a person who advocates or promotes preservation, especially of wildlife, natural areas, or historical places.

Origin of preservationist

1925–30; preservation + -ist
Related formspres·er·va·tion·ism, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Word Origin and History for preservationist

"advocate of protecting existing things," 1905, from preservation + -ist; specifically of historic buildings by 1957.

Online Etymology Dictionary, © 2010 Douglas Harper