Groundhogs were once endemic to the part of rural Ontario where I grew up.
Our farm was covered in "gopher" holes and the dogs would regularly be dragging ripe ones into the kitchen. Their natural predators had been all but wiped out, allowing the population to explode. They ate much of the ground cover used by other animals and increased erosion.
With the reintroduction of a variety of predators their numbers have plummeted.
The fisher, a cross between a wolverine and a weasel, is particularly good at gopher home invasion and likes to snack upon them enthusiastically. Fishers also like to eat cats, which the local songbirds are quite happy about. I miss seeing groundhogs all over, but I'm glad the predators are back.