On December 4, 2012, the U.S. District Court for the District of Idaho denied a request to amend its previous order reversing the U.S. Fish and Wildlife Service’s (Service) 2009 Final Rule listing the slickspot peppergrass (Lepidium papilliferum) as threatened under the Endangered Species Act (ESA).  Plaintiffs sought to reverse the court’s August 2012 decision (pdf) to vacate the Service’s determination in order to allow the listing to remain in place pending additional review.

The ESA defines "threatened" as "likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range."  The court based its decision to vacate the listing on the Service’s failure to adequately define "foreseeable future" as it applied to the species.  The Final Rule defined "foreseeable future" as "that time period over which events can reasonably be anticipated."  The court found that this definition was too generic, and that the definition of "foreseeable future" must be made on a species-by-species basis and through an analysis of time frames applicable to the particular species at issue.  It remanded the issue to the Service for further consideration.

The Service published its Final Rule listing slickspot peppergrass as threatened on October 8, 2009.  Multiple parties, including Idaho Governor C.L. "Butch" Otter (R), sued the Service contending that: (1) the listing was not based upon the "best available science"; (2) a species may only be listed under the ESA if it is likely to become an endangered species in the foreseeable future, and the Service failed to provide an adequate definition of the "foreseeable future" in its Final Rule; (3) the Final Rule improperly discounted the significance of state conservation efforts; and (4) the Service failed to provide the State of Idaho with a letter outlining the justifications for the listing, which is required under section 4 of the ESA when a state files comments disagreeing with all or part of a proposed regulation.

Slickspot peppergrass is a small, flowering plant in the mustard family.  It is endemic to Idaho, and has never been found outside of the state.  The species is found in "slickspots," which have been described as small circular patches of ground with unusual soil chemistry that create visually distinct openings in the surrounding sagebrush environment.  Scientists believe that the slickspots took thousands of years to form and, once destroyed, cannot be re-created. 

The litigation was the fourth occasion since 2001 that a federal court had been asked to review a decision by the Service concerning whether slickspot peppergrass should be listed as threatened or endangered.