Preservation administrators are librarians who are trained in the management of preservation

Preservation (library and archival science)

Preservation is a branch of library and information science concerned with maintaining or restoring access to artifacts, documents and records through the study, diagnosis, treatment and prevention of decay and damage....

 in libraries and archives. The term is often used as a parallel term to conservator

Conservator

A Conservator is a judge delegated by the pope to defend certain privileged classes of persons — as universities, Roman Catholic religious orders, chapters, the poor — from manifest or notorious injury or violence, without recourse to a judicial process...

, an allied profession that is focused primarily on the corrective repair of artefacts. The term "preservationist" has fairly wide usage as a synonym for "preservation administrator" or a broader term for anyone active in the fields of conservation or preservation, but has never found professional favor.