There is no direct way doing this…but you may explore lock/unlock mechanism how the WmRoot services does that internally or monitor the underlying package/particular flow.xml or node.ndf files whether any changes occur in the file system and logic to send a notification email sort of.
Vithya,
Looks like you already have different users defined. You should now create groups, assign users to respective groups, ACL’s and provide restrictive access to different groups instead of making everyone access everything & later monitor through an email who accessed what/why…
Apart from above security best practice prescribed by Senthil, If you really want to track the service modifications better to implement the version control for the source code. it enables you to track the changes, view the logs and generate the reports.