Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for Ambrosia pumila (San Diego Ambrosia) from Southern California

We, the U.S. Fish and Wildlife Service (Service), determine endangered status for Ambrosia pumila (San Diego ambrosia) pursuant to the Endangered Species Act of 1973, as amended (Act). This plant species is restricted to 15 known occurrences in San Diego and Riverside Counties, CA, and also occurs in Estado de Baja California, Mexico. Ambrosia pumila primarily occurs on upper terraces of rivers and drainages as well as in open grasslands, openings in coastal sage scrub habitat, and occasionally in areas adjacent to vernal pools. This species is threatened by the following: present or threatened destruction, fragmentation, and degradation of habitat primarily by construction and maintenance of highways, maintenance of utility easements, development of recreational facilities, and residential and commercial development; inadequate regulatory mechanisms; potential competition, encroachment, and other negative impacts from non-native plants; mowing and discing for fuel modification; and trampling, as well as soil compaction by horses, humans, and vehicles. This rule implements the Federal protection and recovery provisions of the Act for Ambrosia pumila.