In October 1988 the Stephens' kangaroo rat (SKR) was listed as an endangered species by the U.S. Fish and Wildlife Service (USFWS). Under the Endangered Species Act (ESA), both the SKR and its habitat were protected from any type of disturbance resulting in "take" of the species. The net effect was to freeze new development on more than 22,000 acres throughout western Riverside County. At the time of listing very little was known about the animal, its geographical distribution, or its habitat needs.
In order to address severe economic impacts of the SKR listing, the RCHCA prepared a Short-Term Habitat Conservation Plan (HCP). This HCP, approved by the USFWS and CDFG in August 1990, was intended as an interim conservation program designed to afford protection to the SKR while a plan providing for the establishment of permanent preserves could be developed.