St. Francis was known for his love of animals, but not in the same way he loved other people, created in God's image. St. Francis believed that all of God's creation is worthy of our respect by virtue of the Author. Indeed, he even believed in the hierarchy among the animals. The scholastic view of creation similarly regards man as the noblest part of creation. He has a soul, which separates him from the rest of creation.
Humans have transcendent life, where the animals have only a temporal existence.
In the Genesis account, God commanded man to mix his labor with creation to make more of it than what appears to us in the state of nature. God's covenant with Adam requires him to exercise dominion over the earth, His gift to us for our use. We cannot keep man from his surroundings, from nature, from the environment. Nature does not have a metaphysical right to be left alone, to be preserved and adored for reasons other than its usefulness to God's human creation. This is what environmentalists find so objectionable.