Opinion of the Court
eradication of the frog’s habitat sent the species into severe decline. By 2001, the known wild population of the dusky gopher frog had dwindled to a group of 100 at a single pond in southern Mississippi. That year, the Fish and Wildlife Service, which administers the Endangered Species Act of 1973 on behalf of the Secretary of the Interior, listed the dusky gopher frog as an endangered species. Final Listing 62993–62995; see 87 Stat. 886, 16 U. S. C. §1533(a)(1).
B
When the Secretary lists a species as endangered, he must also designate the critical habitat of that species. §1533(a)(3)(A)(i). The ESA defines “critical habitat” as:
“(i) the specific areas within the geographical area occupied by the species… on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protection; and
“(ii) specific areas outside the geographical area occupied by the species… upon a determination by the Secretary that such areas are essential for the conservation of the species.” §1532(5)(A).
Before the Secretary may designate an area as critical habitat, the ESA requires him to “tak[e] into consideration the economic impact” and other relevant impacts of the designation. §1533(b)(2). The statute goes on to authorize him to “exclude any area from critical habitat if he determines that the benefits of such exclusion outweigh the benefits of [designation],” unless exclusion would result in extinction of the species. Ibid.
A critical-habitat designation does not directly limit the rights of private landowners. It instead places conditions on the Federal Government’s authority to effect any physical changes to the designated area, whether through
