Range collapse in the Diana fritillary, Speyeria diana (Nymphalidae)
- Global warming can affect the distributions, phenology and, ultimately, conservation status of species worldwide, but most published studies on its biological effects have focused on higher latitude species. We extended this work to the Diana fritillary, a butterfly which once ranged throughout the Southeastern United States but now is severely restricted in range.
- We searched for all scientific records of this species, from publications, catalogued and uncatalogued specimens in public and private collections in the United States and Europe, online databases, contemporary field surveys by scientists and amateurs, and our own field surveys. We analysed these records for shifts in latitude, longitude, elevation and phenology.
- We found that the Diana fritillary has disappeared entirely from the Atlantic coastal plain, where it was first described, and from interior lowland sites. It now persists in two disjunct parts of its former range, the Southern Appalachian Mountains and the Interior Highlands of Oklahoma and Arkansas, and is shifting to higher elevations at about 18 m per decade. In addition, females are being collected 4.3 days earlier per decade though males, which emerge first, have not shifted their phenology. All these patterns are weakly dependent on latitude.
- These shifts in distribution and phenology are consistent with the predicted effects of global warming, but we review other large scale changes to the region which also might contribute singly or jointly to these patterns. We also comment on the implications for the conservation of this species.