[jasonfarnon]

Do universities require staff to perform a certain number of reviews in academic journals?

Depends on what you mean by "require". At most research universities it is a plus when reviewing tenureship files, bonuses, etc. It is a sign that someone cares about your work, and the quality of the journal seeking your review matters. If it were otherwise faculty wouldn't list the journals they have reviewed for on their CVs. If no one would ever find out about a reviewers' efforts e.g. the process were double blind to everyone involved, the setup wouldnt work.