I especially like this essay and excerpt:
Rule No. 7 - You are allowed to compete with other species for food, but not to wage war on them.
As Daniel Quinn points out in his book, Ishmael, lions may not like the hyenas that compete with them for food and territory and will sometimes pick fights with them, but lions don't organize all-out, genocidal war against hyenas as you humans do against any species that dares to eat "your" food, with your pesticides that indiscriminately poison everything that comes near "your" crops, or your "predator control" programs that seek to exterminate the bears, wolves, coyotes, foxes, raccoons, hawks and eagles, etc., that occasionally prey on "your" sheep, cattle, chickens, etc.
What you humans fail to realize is that trying to deny competing species access to the food that you claim as yours alone can only lead to eventual ecological devastation. The other species that compete with you for food exist for very good reasons: Because biodiversity helps preserve ecosystem stability and health (see Rule 5, above) and because they form an important part of the food chain. Just one of many examples: Wolves do not just eat "your" sheep or cattle, they also eat deer, and the extermination of wolves in much of North America has therefore led to widespread ecosystem damage due to the severe overpopulation of deer in such areas as the northeastern U.S.
This is one of the reasons why Timberwolves were wiped out in the State of Wisconsin during the early 1900's. It would be nice if atleast the Wisconsin Department of Natural Resources would acknowledge this.
I don't think there is any argument that can stand against the rule quoted above (In other words The Biological Law of Limited Competition as talked about in the Ishmael Trilogy).