Riparian zones can be identified by the presence of vegetation that requires free or unbound water or conditions that are more moist than normal (fig. 1) (Franklin and Dyrness 1973, Minore and Smith 1971). Riparian zones can vary considerably in size and vegetative complex because of the many combinations that can be created between water sources (fig. 2) and physical characteristics of a site. Such characteristics include gradient, aspect, topography, soil, type of stream bottom, water quality, elevation, and plant community (Odum 1971). All riparian zones within managed rangelands of the western United States, however, have the following in common: (1) they create well-defined habitat zones within the much drier surrounding areas; (2) they make up a minor proportion of the overall area; (3) they are generally more productive in terms of biomass-plant and animal-than the remainder of the area; and (4) they are a critical source of diversity within rangelands (fig. 3). Carothers (1977), Carothers and Johnson (19751, and Curtis and Ripley (1975) have prepared summary papers on the subject of riparian habitats as associated with both range and forest areas.