The encyclical letter Laudato Si is available here on the Vatican website. The human role in Creation is not some kind of mindless default: just because we can trample everything does not mean that our God-given intelligence makes it a mandate.
68. This responsibility for God’s earth means that human beings, endowed with intelligence, must respect the laws of nature and the delicate equilibria existing between the creatures of this world, for “he commanded and they were created; and he established them for ever and ever; he fixed their bounds and he set a law which cannot pass away” (Ps 148:5b-6). The laws found in the Bible dwell on relationships, not only among individuals but also with other living beings. “You shall not see your brother’s donkey or his ox fallen down by the way and withhold your help… If you chance to come upon a bird’s nest in any tree or on the ground, with young ones or eggs and the mother sitting upon the young or upon the eggs; you shall not take the mother with the young” (Dt 22:4, 6). Along these same lines, rest on the seventh day is meant not only for human beings, but also so “that your ox and your donkey may have rest” (Ex 23:12). Clearly, the Bible has no place for a tyrannical anthropocentrism unconcerned for other creatures.
In other words, God gives a mandate to sensitivity, observation, and action.