Mason, K.R. 2001. Comparison of prairie sites and classification of their habitat attributes in relation to abundance of the Regal Fritillary Butterfly (Speyeria idalia). Final report submitted to the Minnesota Department of Natural Resources. 26 pp.
Habitat and landscape attributes of eighteen prairie fragments in western Minnesota were considered in relationship to abundance of the regal fritillary butterfly, Speyeria idalia, in 1997 and 1998. Regal fritillary butterflies, their larval host plants (Viola spp.), and adult nectar sources were counted at each site. Environmental factors affecting variability in abundance (temperature, sunshine, wind speed, cloud cover, and site moisture) were also recorded. The objective was to determine whether regal fritillary abundance at these sites was related to patch size and proximity to other potential regal fritillary habitat. Analysis of the data, using stepwise linear regression, showed that the area of contiguous, road-free habitat available at each site accounted for more than 60% of the variance in regal fritillaries observed. An additional 11% of the variance was attributable to moisture conditions at the sites. Proximity of the sites to suitable but non-contiguous habitat did not show a significant effect.