briantrumpet
Timewaster
But the problem is that people *have* come along, and putting the genie back in the bottle isn't easy. We now have invasive species of flora and fauna which, without management would just destroy "natural" woodland, so we need to manage it. To pull back the damaging knotweed, ivy, and other plants, or to cull animals such as deer which would have an out of control population, destroy woodlands and have far more disease and suffering without human management.
Another example would be grey squirrels coming over on small boats. I'd suggest it's not enough to screw it up by throwing our borders open and then saying "Tough, suck it up!" to the patriotic British Squirrels and their legitimte concerns.
And remember, red squirrels are much safer on the roads, because they drive slowly.