Watershed Restoration: Principles and Practices

Chapter 5: Historical Perspectives

R. C. Wissmar

doi: https://doi.org/10.47886/9781888569049.ch5

A common goal for restoring watershed ecosystems is to return them to “natural conditions.” This means restoring their original conditions—as we perceive them—of structure (e.g., species diversity) and function (e.g., plant productivity, feeding, and migration) This “natural conditions” goal is derived from certain perspectives, correct or incorrect, of past ecosystems. They are believed to have existed as abundant natural habitats, to have had diverse species assemblages and abundant populations, and to have enjoyed self-regulating and sustainable processes that buffered nature’s cycles. Although a “natural conditions” restoration goal is laudable, it must be viewed with caution because our expectations and the capacity of restored ecosystems to recover can easily be confounded by the complex interaction of natural processes and human activities (NRC 1992a).

This chapter describes how an environmental history (retrospective analysis) of changing watershed and river conditions can improve our understanding of aquatic ecosystems (e.g., streams) and riparian ecosystems (shore and stream-bank), and thus their restoration.