The costs associated with enforcement of the Endangered Species Act (ESA) are constantly increasing as the act is applied in new ways and to additional species, subspecies and dis-tinct populations of plants and animals.

The U.S. Supreme Court has ruled that Congress intended the protection of species to include habitat protection, ensuring that conflicts over land use will increase. A few cases illustrate the large economic impact listing a species can have:

• Listing the Northern spotted owl in 1990 led to tens of thousands of job losses and is expected to cost the economy $21 billion to $46 billion.

• The price of a new house in the Sacramento, Calif., area is expected to rise about $6,000 due to protection of the fresh water fairy shrimp.

• Cutoff of the water supply for San Antonio, Texas, is threatened by the proposed listing of such obscure species as the Comal Springs riffle beetle, the Comal Springs dryopid beetle and the Peck's Cave amphipod.

The U. S. Fish and Wildlife Service has catalogued 4,400 domestic species to review for possible future inclusion on the endangered list. Based on past inclusions, this suggests that the species whose habitats are protected will more than triple from 962 to between 3,100 and 3,600 in coming years.

Only 24, or 1.6 percent, of the 1,524 species (962 domestic and 562 foreign) ever listed have been delisted — in most cases for reasons unrelated to the ESA. Eight of the delisted species were extinct, eight others were found to be more populous than originally thought and eight are classified as recovered (four due to discovery of additional populations).

Source: Thomas Lambert, "The Endangered Species Act: A Train Wreck Ahead," Policy Study No. 126, October 1995, Center for the Study of American Business, Washington University, Campus Box 1208, One Brookings Drive, St. Louis, MO 63130, (314) 935-5630.