Proof of Free Market Environmentalism's viability?

Apparently the Irvine Co. set aside 50,000 acres of its own land for conservation. The OC Register touts this as proof that FME works. I want to believe in FME, I really do, but so far most of what I've read are ipse dixit accounts that fail to explain how markets are being created to govern conservation behavior. Even this article describes the grant as a "gift." As far as I'm aware, that word doesn't exist in pure economics language. When we are governed by market forces as opposed to conservation morals, we don't give "gifts" unless we are looking for something in return. Responsible advocacy of FME would explain exactly what the Irvine Co. is getting in return.