Eisenia foetida will not live in bare soil and there is not enough vegetable mater on the forest floor to feed an exploding worm population. The scavengers moles,voles, mice, large bugs,birds .will home in on any quanity or concentration of worms and keep the masses under control.i tried to start a herd in my flower garden .eventhough i had manure there for bedding the moles ate them all.

wellsworms is correct that Eisenia fetida (Red Wigglers) will not live in bare soil, but I do think that a forest floor / duff has plenty of organic material to allow them to thrive and to expand to the limits of the forested area.

I think the real question is whether Eisenia fetida is already present in your area. Chances are excellent that it is either already present, or can't survive winters there.

My academic background is as a conservation biologist, and I've done a lot of research on invasive species. At this point, Eisenia fetida has probably already been spread to almost everywhere that they can survive. I would consider them to be almost in the same category as standard livestock species. No one worries about introducing cows, chickens, cats, or dogs into a new area within the mainland U.S. -- not because they can't be destructive, but because they're already established anywhere that they can survive.

When I first stared with worms, I, too, was concerned about introducing an invasive species. Now that I know widespread they are, I don't worry about it. If they don't happen to already be in your exact area, they will be. There's virtually no chance of preventing Red wigglers from expanding into all areas of North America in which they can survive. In fact, I'm not certain they're not actually native to the U.S. I can't find any information as to where the species actually came from, and whether or not it was already here before Europeans (the people, not the worms) arrived.

Bucky wrote:

QUOTE:

For now, I've got the project on hold as I don't want to be responsible for a tragic worm population explosion in the NJ woodlands.

Trust me . ANYTHING that you do to New Joisey would be a definite improvement .(That coming from a former Noo Yawker)

I mis-read your original post -- thought you were in Minnesota rather than New Jersey. If you're in New Jersey, I can almost guarantee you do not need to worry about introducing Eisenia fetida as an invasive species. In an area so heavily populated an human-impacted as NJ, I'm sure that Eisenia fetida is already there.

While there may be nearly untouched wilderness in northern Minnesota where Eisenia fetida is not currently present, I'd be extremely surprised if there are suitable areas in New Jersey where the species is not already established.

I agree with someone else's suggestion if you need to prove this to superiors. put down a pile of horse manure in a shady spot, and just let it sit for a month or so. If you dig it up and find Eisenia fetida, then there's no concern about introducing them to your area.