The Western Viceroy butterfly (Nymphalidae: Limenitis archippus obsoleta): an indicator for riparian restoration in the arid southwestern United States?

Life history characteristics of the Western Viceroy (Limenitis archippus obsoleta), an obligate riparian nymphalid butterfly in the desert southwestern United States, are described and related to Colorado River riparian restoration efforts. Riverine disturbance regimes and associated fluvial and hydrological dynamics may provide resources critical to this butterfly. Puddling by adult butterflies may require flood-cleared surfaces and an obligate riparian plant, Gooddings willow, was a larval host plant. This butterfly needs a variety of resources that are only found in close proximity in naturally functioning riparian ecosystems. Habitat heterogeneity required for colony persistence depends largely upon the natural dynamic character of flowing water systems. Because of the links between this butterfly and riparian structure and function it may be a useful indicator for monitoring riparian ecosystem restoration in the area.