Abstract

Conservation and restoration programs usually involve nostalgic claims about the past, along with calls to return to that past or recapture some aspect of it. Knowledge of history is essential for such programs, but the use of history is fraught with challenges. This essay examines the emergence, development, and use of the “ecological baseline” concept for three levels of biological organization. We argue that the baseline concept is problematic for establishing restoration targets. Yet historical knowledge—more broadly conceived to include both social and ecological processes—will remain essential for conservation and restoration.