Livestream allows you to choose whether or not to send a notification to your subscribed followers on Livestream when you go live via Mevo.
Navigate to Livestream's settings by tapping the More Options icon in the lower right corner of the live edit view, followed by the gearwheel.
Select the Live Streaming menu.
The fourth option down is Notify Followers. By default, this will be toggled on, thus sending an email or push notification to any followers who have subscribed to notifications on Livestream.
Tap the switch if you wish to toggle it off and disable notifications from being sent.