Indiana's system of natural area reserves is evaluated to assess the system's conservation value for imperiled butterflies. This system of nature reserves was designed to conserve representative examples of all terrestrial community types present in the state. It is one of the more long-lived attempts to develop a representative conservation system in the United States. The system of complementary reserves appears to be conserving most of the state-imperiled butterfly fauna. Of the 38 species evaluated, 32 are known to occur on sites that are either part of the reserve system or on sites that have been identified as priority additions to the system of reserves. There are 187 known populations of state-imperiled butterflies within the nature reserve system and on other public lands. Species with specialized habitat requirements such as fen, prairie, glade and oak savanna are well represented in the system. The system fares less well at conserving species at the extreme periphery of their range. These species, which have few known populations in the state, are sparingly represented or are missed entirely by the system. A few rare, but widespread, species of forested habitats are also poorly represented in the system.

Four butterflies with discernable phenotypic variation are also evaluated to determine if the reserve system adequately captures phenotypic variability across the state. Divergent populations of all four species were captured within the system.