2017-07-14
Avid Reclaimer's ability is a mana ability. It doesn't use the stack and can't be responded to. You'll immediately add mana and gain 2 life, if applicable.
2017-07-14
You can activate Avid Reclaimer's ability even if you don't have anything to spend that mana on. You'll still gain 2 life if you control a Nissa planeswalker.