As an interesting point - humans are about the only animal life recorded (thus far) which actively destroys its own living environment. Almost all other animals (when not moved across vast distances by people) will cause change, but will eventually settled into a level of balance with the ecosystem they live within. This balance won't necessarily be on an annual basis, but over the longer term whilst populations will shift there will be balance. At a simple level if you have many deer you'll gain many wolves - who will eat the deer and thus lower the deer population. As a result you've less deer and thus fewer wolves can be supported - wolf populations are forced to lower and thus with fewer predators the deer can repopulate (alongside this you'd also have shifts in the deer's food supply - dwindling as the deer population grows and then regrowing as the population of deer reduces). Humans are the only ones which essentially don't operate within this pattern of behaviour - we are capable of moving into an area and actively resulting in the destruction of multiple parts of the ecosystem, even those parts which we make direct use of.