Any changes to monitors will create an event in the stream that explains the change and shows the user that made the actual change.
Assuming you've made changes to your Monitors, you can see examples with the following event search:
We also provide you with the ability to be notified on changes to a monitor you create. At the bottom of the Monitor Editor there's an option to notify alert recipients for all changes to the monitor:
Setting the above to "Notify" will simply send an email for the monitor audit events to all people who are alerted in a specific monitor.