GBA to DS--permanent transfer?

[RBYGSCRSFRLGEPD]

I haven't found much information on the web about transferring Pokémon from a GBA Pak (like Ruby) to a DS Card (like Pearl), except on Serebii--and it was a bit ambiguous on this:
Apparently, it's not a trade, but a one-way transfer...so when you transfer Pokémon from the GBA Pak, are they gone from it permanently? Or does it just copy it into the DS Card?

 

[Doctor Oak]

When you transfer your Pokemon from R/S/E/Fr/Lg to D/P, they are erased from the Advance games, so yes - it's one way.

There are ways to circumvent it via cloning I think though.

 

[Habunake]

Yeah. I send them to Emerald then clone em, then transfer.