Alien invaders on the loose!

I have just been reading my local paper. It has a page on Himalayan balsaam and japanese knotweed. Here in britain the marines have been called in yanking up these plants.

Ok so it is threatening our countryside. But yanking them up, wont that then leave the ground bare? What can they be used for and is there any truth in what these plants do? The bees love them.

there must be another way, I hope I dont read that they have taken to chemicals.