On January 8, 2011, a federal district court overruled (pdf) a 2008 decision by the U.S. Fish and Wildlife Service (Service) to reduce the acreage of critical habitat designated for the San Bernardino kangaroo rat from 33,290 acres to 7,779 acres. The Service had initially designated the 33,290 acres in 2002, but decreased the amount (pdf) in 2008 after a lawsuit successfully challenged the designation. The district court’s ruling reinstates the area designated as critical habitat in the 2002 rule (pdf) in San Bernardino and Riverside counties until a revised designation is completed.

In the decision, the United States District Court for the Central District of California held that the Service had violated the Endangered Species Act (ESA) by improperly relying on “core populations” of the kangaroo rat to determine critical habitat. The court reasoned that the Service was required by the ESA to define critical habitat by evaluating the physical and biological features essential for the kangaroo rat’s conservation, rather than solely relying on habitat areas that support the species’ core populations.

Activities within areas designated as critical habitat for the species that also have a federal nexus may be subject to regulatory requirements that would not otherwise be imposed. According to the San Bernardino Sun, mitigation costs added approximately $650,000 to the Greenspot Road bridge project completed a few years ago in the habitat area. Two new bridges are slated to be built in the new critical habitat areas, with combined mitigation costs estimated at $2.4 million.