Leopold's Land Ethic

Leopold wants to think about ethics in evolutionary terms.  His background is as a biologist.  Philosophically speaking, an ethic is what distinguishes social from anti-social behavior.  In other words, an ethic says what you should and should not do.  Ecologically speaking, an ethic is a restriction on individual behavior in the struggle for life.  Leopold says that the sequence of ethical evolution is to recognize a broader range of entities as being morally relevant.  For example, in the history of Western Civilization, women and various other minorities were, at one point or another, thought to be morally irrelevant.  Many humans were once considered property.  Property issues are not moral issues.  But just as we now recognize that women and minorities are not property, Leopold thinks that we have good reason to think of land as more than property.  Land has moral value even if we do not love, respect or admire it.

What is the basis of the value of the land?  Leopold describes what he calls the land pyramid.  At the base of the pyramid is the soil.  Plants live on the soil, insects live on the plants, rodents and birds live on the plants, and smaller predators live on birds, rodents and plants.  Apex predators occupy the top of the pyramid, as they are consumed by no other creatures.  Beings near the top feed off of beings lower on the pyramid.  Beings at the bottom are nourished by the decaying matter of higher species.  Leopold  says that the way this biological community functions is like an energy circuit.  Energy (nutrition, calories) transfers from the lower levels to the higher levels and back down.  Natural and native species keep this energy circuit open.  Sometimes, invasive or introduced species interrupt this energy circuit.  For example, the kudzu vine will cover all native plant species and rob them of energy from the sun.  When local plants die, local insect populations do not get appropriate nutrition.  Hence, local rodent and bird populations suffer, as well.  Eventually, this domino effect reaches apex predators.  Whereas natural changes in biological communities are slow and local, man-made changes are fast and large-scale. 

Humanity can either think of itself as a conqueror over nature or as in community with nature.  Leopold says that attempts to be conquerors will be self-defeating because true domination and control require perfect knowledge of how nature functions.  Because we lack this perfect knowledge, we cannot control nature.  Also, a long history of attempts to control nature show that our scientific and technological efforts are often met with negative consequences that are neither foreseen nor intended.  As such, we should recognize that just as species within a biological community have co-evolved in order to function as a larger system, we are also part of the biological community.  We are not masters of nature.  We are in community with natural systems and species.