The Center for the Study of World Religions at Harvard Divinity School has published a series of books, "Religions of the World and Ecology." These are excellent resources, containing information written by experts. The Gustavus library has the entire series. Use the call number information to locate the book on our shelves.
As an aside, even just searching "religion and ecology" in the catalog brings back a number of useful books.
Books are shelved in general subject categories using the Library of Congress classification system. You may want to supplement your use of the catalog with browsing shelf areas for your topic. Note, these are just some of the possible topics.