Regal Fritillary - Declining Populations

Declining Populations

With a loss of more than 99% of the original native tallgrass prairie landcover today (Powell et al. 2006), decreased sustainable habitat area for the regal fritillary has become a real threat. Drastic declines in regal fritillary populations have led to much concern about the butterfly’s future (Kopper et al. 2001). Historically, the regal fritillary’s range extended from eastern Colorado to Maine. However, due to habitat loss and large-scale population declines, their range has been far reduced, especially in the east.

From the 1960s through the early 1990s, eastern populations had crashed so severely that only a few eastern populations remain (Powell et al. 2006). The regal fritillary was once present in 18 states east of Illinois. Today, only three populations remain in the eastern region. These populations have been located in Indiana, Pennsylvania, and Virginia. Populations in the Midwest and Great Plains are much more widespread; however, they remain extremely vulnerable as their numbers continue to decline. The regal fritillary is not federally listed as an endangered species; however, it has been assigned a NatureServe conservation status of G3 which is considered vulnerable (Selby 2007). S. idalia was a Category II species, or a possible candidate for listing under the Endangered Species Act until 1996 when this category was eliminated by the federal government (Kelly and Debinski 1998).