Original:  Roles and responsibilities vary widely depending on the type of library and specialist librarian, from academic libraries to public libraries, as well as the functions needed behind the scenes to maintain the collection and make it available to its users.
Revised:  Roles and responsibilities vary widely depending on the type of library and specialist librarian, from academic libraries to public libraries, as well as the functions needed to maintain collections and make them available to its users.
Edit intent: clarity