PARENT SESSION
Oral Session #79: Conservation Ecology: Biodiversity Case Studies and Models. Presiding: T. Rooney.
Friday, August 10, 2001. 8:00 AM to 12:00 PM. Hall of Ideas J.

Spatiotemporal dynamics of endangered species hotspots in the United States.

Rutledge, Daniel ¹, Lepczyk, Christopher ¹, Xie, Jialong ¹, Liu, Jianguo¹, ¹

ABSTRACT- Given limited resources, many researchers advocate focusing conservation efforts on hotspots. The hotspot approach represents an efficient and simple approach towards conserving species diversity, assuming that hotspots do not change over space or time. To test whether this assumption is valid, we used a database of endangered and threatened species listed in the U.S. from 1967 to 1999. We determined hotspots (i.e., counties) based on the cumulative set of species listed for three overlapping and successively longer time periods: 1967-1979, 1967-1989, and 1967-1999. Over time the number of listed species increased from 76 in 1967 to 1,123 in 1999. As the number of listed species increased over time, hotspots changed in two ways: the number of hotspots increased and the rank of hotspots shifted. Hotspots increased from 84 in 1979, to 166 in 1989, and to 217 in 1999. Only 63 hotspots remained in all three periods. The other changes resulted from additions and deletions of counties as hotspots over time. Counties were removed from the list or changed in relative rank from one time period to the next regardless of their rank. Counties added as hotspots could rank anywhere on the list and were not merely low-ranking counties added to represent one or a few species. Therefore, hotspots serve as a useful tool for guiding conservation efforts but do not represent a final solution given their spatiotemporal variability.

KEY WORDS: endangered species, hotspots, spatiotemporal dynamics, conservation