Cabrillo National Monument - Environmental Factors

Cabrillo National Monument by National Parks Service

Cabrillo National Monument is a naturally beautiful promontory affected by numerous environmental factors and influenced by a nearby city and port. The monument contains 67 hectares (160 acres) at the tip of the Point Loma peninsula. The peninsula elevation reaches 129 m (422 feet.) It is bordered to the west by the Pacific Ocean, on the east and south by the San Diego bay, and on the north by an urban environment. The portion of the peninsula that is not owned by the National Park Service is divided among the U.S. Navy, U.S. Coast Guard, the City of San Diego, and the U.S. Department of Veterans Affairs. All of these landowners have collaborated and established the Point Loma Ecological Reserve (PLER), which covers 268 hectares (662 acres), in order to enable management of the natural resources on the entire peninsula. The peninsula is comparable to an island because of the aquatic borders and the urban landscape to its north. Sources of factors that continually influence the monument and the PLER are the North Island Naval Air Station across the bay, the San Diego airport 11 kilometers (seven miles) to the northeast, and the city of San Diego, an urban environment surrounding the park. Air quality issues include pollution from vehicles which compromise the views from the scenic overlook at the monument's Visitor Center. There are a number of influences on the soundscape including military aircraft, commercial aircraft, the fog horn on the jetty, Coast Guard and Navy activity, vehicular traffic and operation of the Point Loma Waste Water Treatment Plant. San Diego Bay is a major port of entry, especially for ships traveling north from Mexico. The Navy operates several bases with direct access to the San Diego Bay including Naval Base Coronado, Naval Base San Diego, and Naval Base Point Loma (with associated submarine bases). The U.S. Coast Guard also actively uses the bay for daily operations and maneuvers. Water quality is affected by the industries around the bay, and commercial, governmental, private, national, and international ships and boats. Personal watercrafts are also used in the bay and are a source of pollution. The City of San Diego operates a Wastewater Treatment Plant north of the monument's intertidal area. This plant treats 180 million gallons per day of sewage and deposits the treated effluent six kilometers (four miles) offshore at a depth of 122 meters (400 feet). In 1992 an accidental leak released effluent along the rocky intertidal coast. There is no current direct discharge, but there is an on-going possibility of a leak.

Non-native species are the biggest threat to the park. These are sometimes called "exotics." Exotics are plants and animals that are not from the monument's coastal sage scrub and marine communities, but have somehow been introduced (either accidentally or intentionally) to the environment and adapted to it. Exotic species can be detrimental to native species. One example of this is the non-native Argentine ant. These ants have displaced the native ants and have caused major problems for the coast horned lizard population. The coast horned lizard survives on native ants, and does not eat the Argentine ants. In those areas where Argentine ants have established colonies, the coast horned lizard has died off and no longer exists. This has occurred at the park where insufficient number of native ants and a lack of habitat no longer allow the coast horned lizard to exist