I saw in the reputation dropdown a -2 for this site.
On inspection my reputation tab looks as follows. Both of my positive reputation entries come from approved edits - how can these be affected by user removal?
You edited a post as a low-rep user.
That suggested edit was approved and you earned 2 rep for that.
Now a relatively low-rep user account was deleted and the rep-gain for the approved edit was reversed, as it was approved by that now removed other user.
seems to be the post in question?
Approval now owned by "Community♦ reviewed this Jan 2 '17 at 16:23: Approve"
As explained here, on Meta.Stackexchange: How does "Reputation" work?
The account of a user who was the final approver of a suggested edit you made has been deleted (reputation page shows the cause as User was removed): −2