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12 / Riparian Ecosystem Recovery Healthy versus Degraded Ecological Condition In conservation literature, the term ecological condition (or ecological health) is often used, yet rarely defined. It is a nebulous term whose definition often depends on management objectives. For example, an ecologist developing a management plan to preserve spotted owl (Strix occidentalis) habitat in the Pacific Northwest will have an entirely different set of criteria for determining the ecological condition of a forest ecosystem than would a forester cruising timber. The term healthy as used here describes a riparian ecosystem with a high diversity of native plant species, and one that has not experienced dramatic changes in structure (e.g., age- or size-class, composition, diversity, biomass) or functional elements (e.g., changes in erosion rates, flow regime, ground- water, channel morphology, productivity) in comparison to its pre-Anglo-set- tlement condition. A degraded or damaged ecosystem is defined by the reverse of the above. The word degrade is also used differently by the various science disciplines. Ecologists often use degrade to describe a reduction in the ecological condition of an ecosystem; hydrologists to describe adjustments in channel profile. Here, degrade is used mainly to describe a decline in ecological condition. However, in chapter 6, degrade is also used to describe channel conditions: the emphasis in this chapter on hydrology and drainageway conditions made the overlap of definitions unavoidable. Recovery Generally, there are three possible end points for efforts undertaken to im- prove the condition of an ecosystem that is in less than pristine condition: res- toration, rehabilitation, and replacement/reallocation (Bradshaw 1988; Aron- son et al. 1993). Restoration is an attempt to create an ecosystem exactly like the one that was present prior to disturbance. Rehabilitation creates an eco- system that is similar (but not identical) to the ecosystem that was present prior to the disturbance. Replacement or reallocation strategies generally do not attempt to restore an ecosystem to its predisturbance condition but instead are intended to replace the original ecosystem with a different one. The term recovery is used when the objective is unclear: recovery may be used to refer to any type of project (restoration, rehabilitation, or replacement) that is under- taken to improve the condition of degraded riparian ecosystems.