In this extensive online report, the authors give estimated declines of natural ecosystems in the United States, provide a rationale for ecosystem-level conservation, discuss decline and threat as criteria for conservation, and relate ecosystem losses to endangerment at species and population levels. They further recommend that integrated conservation plans for ecosystems be developed in partially disturbed as well as in pristine sites to restore native biodiversity to those areas. Ecosystem conservation is not considered a substitute for species-level conservation. The undated report appears to be from about 1995.