The Suitability of Butterflies as Indicators of Ecosystem Condition: A Comparison of Butterfly Diversity Across Stand Treatments in Northern Arizona Kerry L. Griffis Department of Fisheries and Wildlife Utah State University Logan, UT 84341-5210 Sheri S. Mann Agriculture, Health, and Natural Resource Extension American Samoa Community College Pago Pago, American Samoa 96799 and Michael R. Wagner School of Forestry Northern Arizona University Flagstaff, AZ 86011 Abstract. Past human activities have resulted in a broad spectrum of ponderosa pine (Pinus ponderosa) stand conditions on the Colorado Plateau. A team of researchers at Northern Arizona University’s School of Forestry is using common experimental plots to evaluate how highly-variable forest conditions influence potential ecological indicator species and guilds. Butterflies are one of several insect guilds that we are evaluating. During 1997 and 1998, we monitored populations of adult butterflies within replicated unmanaged, thinned, thinned and prescribed-burned, and wildfire-affected ponderosa pine sites. We did not detect a significant effect of stand treatment on butterfly abundance or similarity at the family level after two years, despite our large plot size (20-80 ha). Important treatment effects may be masked by butterfly movement between plots, heterogeneous forest stand structure, time since treatment, number of stands sampled, climate, and our sampling of adult butterflies. We suggest that sampling effort should be increased and data analyzed at the species level to quantify butterfly response to stand treatment. Key words: Lepidoptera, Pinus ponderosa, indicator species, forest treatments, thinning, prescribed fire, wildfire Email: Kerry Griffis, kerryg@cc.usu.edu 125