Donald Trump's administration has not been bound by the Deferred Action for Childhood Arrivals (DACA) program. The first deportation already occurred in April. There is nothing keeping DACA people from being deported. That's the whole problem with doing the program as an executive action. It only lasts as long as it has presidential support.
The far bigger problem isn't deportations but jobs. People who were legally employable under DACA will lose their jobs when their work authorizations expire. Or their employment would be illegal. That starts happening involuntarily March 6th, 2018 without additional changes. But people in the program could be deported earlier than that.
It's also worth noting that the biggest current effect has been that people have been more reluctant to renew their DACA status under Donald Trump. So some people's work authorizations will expire sooner than that.
The announcement says:
USCIS will adjudicate, on an individual, case by case basis:
- Properly filed pending DACA initial requests and associated applications for employment authorization documents (EADs) that have been accepted as of Sept. 5, 2017.
- Properly filed pending DACA renewal requests and associated applications for EADs from current beneficiaries that have been accepted as of the date of this memorandum, and from current beneficiaries whose benefits will expire between Sept. 5, 2017 and March 5, 2018 that have been accepted as of Oct. 5, 2017.
The part about adjudicating "on an individual, case by case basis" suggests that they can deny renewals prior to March 6th, 2018.
What happens on March 6th, 2018 is that no renewals starting later than that can be accepted without some sort of intervening action by Congress. It's not when they start ending DACA. It's when they've finished everything but waiting for existing authorizations to expire.
They have already stopped taking new applications and renewals. So people who never registered for the program can be deported as of September 6th, 2017. However, as I said earlier, the Trump administration already could (and had) deported people covered by DACA. This just removes that particular appeal as something that the administration could allow.