Humans are not the only ones responsible for altering the earth’s landscape and killing other species. Nature is not a bastion of serenity and peace. Other animals kill each other, often in brutal ways.
Some species of wasp lay their egg in another species and lets the larvae eat their way out while the beast is alive. But if this species became extinct it would be seen as an unmitigated tragedy.
Animals and plants can even modify the environment to the detriment of natural ecosystems. Beavers dams cause rivers to stagnate. Inflated deer populations cause deforestation, as do many arboreal diseases. But, again, if the beaver or the deer became extinct, we would deem it a tragedy.
Humans have a significant impact on the earth, but the extinction of any species is always a tragedy.
Every species offers something unique, be it the wasp or the human. We offer the earth something no other species can; comprehension and rational thought. Therefore, it would be a tragedy if humankind were to become extinct.
Also, animals have no moral standing. As Kant argues, the suffering we cause to other species and the environment is not objectively “immoral” because neither the earth nor other animals have the cognitive capacity to deserve “moral rights”.