Sorry to distract from the actual topic of this thread but to avoid another thread to discuss it, that is the dumbest science I have ever read lol I am not debating you Tamarack, nor am I disagreeing with what you're saying. I simply read this stuff and find it preposterous. I go down these rabbit holes from time to time trying to understand.
So they say "deer spread non-native earthworms" in one article, in the actual study they are referring to, they claim “Deer are peeing and pooping in the forest. And that fertilizes the soil and favors earthworms,”. read that twice so you are sure you grasp what they are saying 🤣 then they say “And then the deer increase the worms which furthers the damage to the plants, which allows the deer to do even more damage, so it's just like an endless cycle.” Apparently Deer are the only things that poop and pee in the forests so we should kill off most of the deer! Things like bears, Elk and farm animals aren't a problem.
They do say they "fenced off a field (so deer couldn't enter it) and the worms were absent." They also say "The researchers also found a link between earthworms and timber harvesting. They found that worm numbers decreased in areas where gaps were cut into the forest." So if I am the scientist doing this study you would normally need to reinforce or prove your claims by putting deer inside the fenced in area currently devoid of worms (or take down the fencing) to prove that deer are the cause of the existence of these non-native worms. But they don't do that.
I am no scientist but it appears to me that these particular worms require shaded areas free from direct sunlight and nothing more. The deer aren't creating this havoc because they DO live, feed and poop in fields and clear cuts, so to make that connection the worms would also be in fields that deer use. But they don't find them there, so the problem is the forested areas, and to prevent this "endless cycle" the real solution would be to cut down all the trees, not kill all the deer! In the actual study they do acknowledge all this, but it is in their 2nd hypothesis and worded "This is likely due to closed canopies having nutrient-rich tree leaf litter, which serves as shelter and food for earthworms" so we found common sense and might save the deer after all lol