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Threatened and Endangered Species Protection and Recovery Efforts

When the Endangered Species Act of 1973 codified the concept of threatened and endangered (T&E) species, it broadened the numbers of animals considered as pests (or damaging species) and greatly increased the range of environments where pest control activities take place. Originally, most government agencies involved in T&E work put their efforts into identifying declining populations, nurturing critical species in captivity for eventual reintroduction, and developing recovery plans. When actual recovery work began, it became evident that producing desirable animals in small, unprotected areas encourages pest problems. In fact, most substantial problems in T&E species recovery can be traced to either competition for food and habitat or direct predation.

Because of their expertise in controlling pest species, wildlifedamage biologists, came to play a significant role in protecting threatened and endangered species throughout the United States, in Puerto Rico, Guam, the U.S. Virgin Islands, Cuba and other locations.

Introduced, nonnative, species such as rats, goats, foxes, and snakes, have been especially devastating to native fauna on islands and in other restricted habitats. Common rodent pest species have spread from ancestral Asian homes to inhabit many natural ecosystems throughout the world. These invasive species often take a severe toll on islands where ground-nesting birds, ground-dwelling animals and burrowing animals are particularly vulnerable to depredation.

Rat colonization of an island can lead to the destruction of populations, rendering surviving animals and birds as threatened or endangered, especially endemic ones. Initiation of rodent control is the often the only chance of saving these decimated populations. (For a good discussion of island rat control see the story of the Anacapa Island Restoration Project) http://www.nps.gov/chis/naturalresources/page2.html Protection efforts in Hawaii go back many years. Early work was aimed at saving waterbirds such as the Hawaiian coot, Hawaiian moorhen, Hawaiian stilt and the Hawaiian duck from feral cats, mongooses, introduced rats and cattle egrets. The nene and Hawaiian dark-rumped petrel also suffered greatly from mongoose predation.

On Guam, the brown treesnake has eradicated 9 endemic bird species and all but wiped out native avifauna. Predator management of red-tailed hawks, black rats, feral cats and Indian mongooses continues as scientists seek desperately to save the Puerto Rican parrot, one of the 10 most endangered species in the world (the only wild population consists of 30-40 birds).

Recent examples of wildlife damage control efforts to aid T&E species include: removal of coyotes to protect the San Joaquin kit fox in California; removal of avian and mammalian predators such as house cats, crows, red foxes, coyotes, raccoons, and kestrels etc. to protect least tern colonies on coastal dunes and beaches; and control of ravens to protect desert tortoise eggs. Ongoing work in Hobe Sound National Wildlife Refuge to reduce raccoon, skunk, rat and dog predation on eggs provides protected nesting habitat for three T&E marine turtles: loggerhead, marine, and green. The USDA's Wildlife Services (WS) has ensured the survival of thousands of sea turtle hatchlings. Before WS went to work in 1997, more than 95% of all hatchlings were lost to predation. WS saved an estimated 120,597 sea turtle nestlings in FY 2002 alone.

Additionally, Wildlife Services biologists' efforts have helped to protect 5 species of beach mice (Perdido Key, Saint Andrews, Anastasia Island, southeastern, and Choctawhatchee); 3 bird species (roseate tern, least tern, and the aforementioned Puerto Rican parrot); and 1 fish species (the Okaloosa darter).

References

ENGEMAN, R. M., S. A. SHWIFF, F. CANO, AND B. CONSTANTIN. 2003. An economic assessment of the potential for predator management to benefit Puerto Rican parrots. Ecological Economics 46:283-292. http://www.aphis.usda.gov/ws/nwrc/is/03pubs/enge035.pdf

ENGEMAN, R. M., R. E. MARTIN, B. CONSTANTIN, R. NOEL, AND J. WOOLARD. 2003. Monitoring predators to optimize their management for marine turtle nest protection. Biological Conservation 113:171-178. http://www.aphis.usda.gov/ws/nwrc/is/03pubs/enge034.pdf

Links

U.S. Fish & Wildlife Service Endangered Species Web site
Endangered Species Act
Endangered Species Update Newsletter