On May 4, 2011, the Solicitor for the U.S. Department of the Interior withdrew (pdf) a controversial 2007 opinion (pdf) (the Opinion) that was recently criticized and rejected by federal courts in Montana and Arizona.  The Opinion provided an interpretation of the phrase "in danger of extinction throughout all or a significant portion of its range" (the SPR phrase). This phrase is key for listing determinations under the federal Endangered Species Act (ESA), as an "endangered species" is defined as "any species which is in danger of extinction throughout all or a significant portion of its range."  The Opinion concluded that:

  1. The SPR phrase is a substantive standard for determining whether a species is an endangered species–whenever the Secretary concludes because of the statutory five-factor analysis that a species is "in danger of extinction throughout . . . a significant portion of its range," it is to be listed and the protections of the ESA applied to the species in that portion of its range where it is specified as an "endangered species";
  2. the word  "range" in the SPR phrase refers to the range in which a species currently exists, not to the historical range of the species where it once existed;
  3. the Secretary has broad discretion in defining what portion of a range is "significant" and may consider factors other than simply the size of the range portion in defining what is "significant"; and
  4. the Secretary’s discretion in defining "significant" is not unlimited; he may not, for example, define "significant" to require that a species is endangered only if the threats faced by a species in a portion of its range are so severe as to threaten the viability of the species as a whole.

Thus, instead of defining an endangered species by its historical range, the Opinion concluded that a species could be listed, or de-listed, based on the status of the species in its current range.  As such, the Opinion purported to authorize the listing or de-listing of portions of a species or a distinct population segment on the basis of spatial (or geographical) considerations.  

The legitimacy of the Opinion rose to the forefront as a result of the litigation surrounding the decision by the U.S. Fish and Wildlife Service (Service) to de-list the gray wolf in Montana and Idaho.  In Defendants of Wildlife v. Salazar (pdf), a federal district court held that the Service’s de-listing of the gray wolf in the states of Montana and Idaho, while leaving federal protections in place for wolves in Wyoming, violated the ESA.  The district court found that the entire region’s wolf population must be listed under the ESA, rather than the wolf’s status varying from state to state.  Accordingly, the de-listing decision was invalidated.

As a result of this decision, Congress passed the first ever bill to effectively de-list a species listed as endangered or threatened under the ESA.  See our posts of December 7, 2010 and April 14, 2011.

While it is not clear how the withdrawal of the Opinion will impact listing decisions in the future, the notice issued by the Solicitor states that the Service intends to "reconsider how it applies the SPR phrase and to develop guidance on how to apply the SPR phrase in making decisions to add or remove species from the lists of threatened and endangered species."