Those things only matter in terms of their value to humanity. There are most probably an uncountable number of planets like Earth out there. The only thing special about this one is that it is our home.
That doesn't mean that we should seek to disrupt the environment. On the contrary, it is very precious to us for many reasons and should be protected. A lot of those reasons are very utilitarian. But it's also because we appreciate its beauty, its complexity, and our kinship with all life. But those are still all things that we value.
How we deal with lower life forms on our own planet is totally unrelated to how we would deal with intelligent life from another. Why would they be related? If you're worried that aliens would look down on us as inferior life forms and wipe us out, that's totally possible, though I'd say it's pretty unlikely that any aliens ever come to visit us anyway. If they do, and they're more powerful than us, our animal welfare laws are not going to do us any good.
That doesn't mean that we should seek to disrupt the environment. On the contrary, it is very precious to us for many reasons and should be protected. A lot of those reasons are very utilitarian. But it's also because we appreciate its beauty, its complexity, and our kinship with all life. But those are still all things that we value.