Controversy over managing public lands is neither an unexpected nor recent development. In the 1970's, debate over land management began to focus on the effects of timber management practices on wildlife. This was most evident in the Pacific Northwest where the public was beginning to express strong concerns about the effects of timber harvest in late-successional forests on northern spotted owls and other vertebrates. The focus on all vertebrates and not just "game animals" distinguished these concerns from earlier wildlife-related issues. In 1976, Congress passed the National Forest Management Act, which mandated the maintenance of biological diversity on lands of the National Forest System. Regulations enacted pursuant to this law specified that viable populations of native and desirable non-native wildlife species would be maintained on planning units (i.e., National Forests) of the National Forest System. Thus, a statutory and regulatory basis was provided for appeals and litigation directed at what the public believed to be the negative effects of timber management practices on wildlife. The many legal challenges that ensued focused primarily on the harvesting of late-successional forests in the Pacific Northwest (see Meslow et al. 1981 for additional discussion).