If humans have value, then nature has value. But while pantheism elevates nature, it simultaneously degrades man and will ultimately degrade nature as well. To the pantheist, man has no more value than a blade of grass. In India the rats and cows consume needed grain and spread disease with the blessings of the pantheists. To restrict the rats and cows would be to restrict god, so man takes second place to the rats and cows.
Man is a part of nature, yet it is man that is being restricted.
So ultimately, all of nature is degraded. Pantheism claims that what is, is right. Pantheism fails because it makes no distinctions between man and nature. A true Christian environmental ethic differs from the naturalistic and pantheistic ethics in that it is based on the reality of God as Creator and man as his image-bearer and steward. God is the Creator of nature, not part of nature.