Preservationist

https://en.wikipedia.org/wiki/Preservationist

Preservationist is generally understood to mean historic preservationist: one who advocates to preserve architecturally or historically significant buildings, structures, objects or sites from demolition or degradation. Historic preservation usually refers to the preservation of the built environment, not to preservation of, for instance, primeval forests or wilderness.

Notable historic preservationists

https://en.wikipedia.org/wiki/Preservationist#Notable_historic_pres...

https://en.wikipedia.org/wiki/Historic_preservation#Influential_people