Sure you can, but you will (from what I can see) have to go to each thread and change your notification. At the bottom of the thread you will see a row of four buttons..."Unread Post", "Subscribed", "Search this Thread", and "Preferences". Click on "Subscribed". This will bring up a window with a small drop-down menu. Click on the black arrow and it should give you the option of "Site Only (no email)"...select that choice and then click on "Submit". Once selected you'll be notified of new replies to subscribed threads when you log onto the forum but you will no longer receive an email notification.
Best wishes,
Ed