What violations of ecological ties can occur in the forest through human fault?

What violations of ecological ties can occur in the forest through human fault? Where it leads? What should be done to avoid such violations?

But because there are animals in the forest that feed on mice and voles.
It is they who do not allow rodents to multiply strongly.
If you cut down all the bushes in the forest, remove the fallen trees, then the birds will have nowhere to breed. This means that soon they will fly to other places. The number of insects will increase. They will harm trees.
After some time, the forest may die.