Since the 1980s, biologists have been concerned about declines in the Mojave Desert Tortoise, which ranges through millions of acres in the western United States. The tortoise was first listed as a threatened species under the Endangered Species Act in Utah in 1980; it was later listed as threatened rangewide in 1990. The listing and designation of critical habitat for the tortoise, as well as recommendations in the tortoise recovery plan, have been controversial. In our report, we evaluate--assisted by scientists identified by the National Academy of Sciences--the scientific basis for key decisions related to the tortoise, assess the effectiveness of actions taken to conserve desert tortoises, determine the status of the population, and identify costs and benefits associated with desert tortoise recovery actions.
The 1990 listing of the desert tortoise, the critical habitat designation, and recommendations in the recovery plan for the tortoise were reasonable, given the information available at the time. Under the Endangered Species Act, listing and critical habitat decisions must be based on the best available scientific and commercial data. These decisions and the recovery plan recommendations were based on sources that reflected existing knowledge about desert tortoises. To protect the tortoise, government agencies have restricted grazing and off-road vehicle use and taken other protective actions in desert tortoise habitat, but the effectiveness of these actions is unknown. Research is underway in several areas, including tortoise disease, predation, and nutrition, but the research has not assessed the effectiveness of the protective actions. Furthermore, the status of desert tortoise populations is unclear because data are unavailable to demonstrate population trends. Before the tortoise may be delisted, populations must increase or remain stable for at least 25 years--one generation of desert tortoises. Determining the trends will cost an estimated $7.5 million in the first 5 years, plus additional monitoring every 3 to 5 years at a cost of about $1.5 million per year of monitoring. The Fish and Wildlife Service depends on other agencies and organizations to assist with funding and monitoring, but these agencies and organizations cannot guarantee assistance from year to year because of other priorities. Expenditures on desert tortoise recovery since the species' first listing in 1980 exceed $100 million, but the exact investment is unknown. The investment includes $92 million in "reasonably identifiable" expenditures for the tortoise, plus staff time valued at about $10.6 million. The overall economic impact of the tortoise recovery program--including benefits as well as the costs incurred by local governments, landowners, and developers as a result of restrictions--is unknown.
Recommendations for Executive Action
|Department of the Interior||To ensure that the most effective steps are taken to protect the tortoise, the Secretary of the Interior should direct the Director of the Fish and Wildlife Service to develop and implement a coordinated research strategy that would link land management decisions with research results. To develop such a strategy, the Director should evaluate current efforts to consolidate scientific information and existing proposals for integrating scientific information into land management decisions.|
|Department of the Interior||To ensure that the most effective steps are taken to protect the tortoise, the Secretary of the Interior should direct the Director of the Fish and Wildlife Service to periodically reassess the desert tortoise recovery plan to determine whether scientific information developed since its publication could alter implementation actions or allay some of the uncertainties about its recommendations.|
|Department of the Interior||To ensure that needed long-term monitoring of the desert tortoise is sustained, the Secretary of the Interior should work with the Secretary of Defense and other agencies and organizations involved in tortoise recovery to identify and assess options for securing continued funding for rangewide population monitoring, such as developing memorandums of understanding between organizations.|
|Department of the Interior||To provide for more timely reporting of expenditures for endangered species, the Secretary of the Interior should direct the Director of the Fish and Wildlife Service to issue the annual expenditure reports as required by the law, and to advise Congress if reports are incomplete because not all agencies have provided the information requested.|