Endangered,
Threatened, and other
Special Status Species of Wildlife in GGNRA
Within GGNRA, there are 69 rare or special status wildlife species currently identified as permanent or seasonal residents of the park or dependent upon park lands and waters for migration. Of these, 12 are listed as federally endangered, 12 are federally threatened, 1 is state endangered, 3 are state threatened, 31 are federal species of concern, and 10 are state designated species of special concern. Numerous other wildlife species (birds in particular) are considered sensitive by the Audubon Society, Partners in Flight, the California Department of Forestry, or are designated Migratory Nongame Birds of Management Concern by the U.S. Fish and Wildlife Service (USFWS). Nearly all of the native birds documented in the park are protected under the Migratory Bird Treaty Act.
Species are endangered, threatened, or have another special status designation because of several factors, which may include the following:
- loss of habitat
- exotic species incursion (both wildlife and plant life which cause habitat changes)
- human disturbances
- toxic pollutants from historical and current practices
Loss of habitat is due to storms (particularly on the coastline) or urban development - for commercial and residential purposes, road construction, and other construction related to an urban area. Urban development and construction may also lead to changes in waterflow to a streambed by increasing urban stormwater runoff. Runoff is rainwater or other water that flows to creeks, rivers, the bay or ocean, which may become high in sediment content or contain pollutants. Construction activities may increase the release of sediments while decreasing the local vegetation, which results in decreased water quality. Many species of plants and wildlife are dependent on water resources for survival, so if this resource is disrupted or unbalanced, their ability to reproduce and survive may be hindered.
Exotic Cape ivy is responsible for the decline of several species in GGNRA - with terrestrial aquatic species and birds being the most affected. Cape Ivy reduces the diversity of indigenous plants and insects in the area - ultimately changing the habitats for several indigenous species. In other cases, the introduction of exotic wildlife species may contribute to the decline of an indigenous species. In one example, the introduction of the exotic bullfrog has contributed to the decline of the indigenous California red-legged frog, due to competition and predation.
Human disturbances may cause unnatural levels of erosion, which leads to losses of plant growth, sedimentation of fish habitats, and other factors that threaten a species ability to reproduce and survive. Human disturbances combined with coastal climate forces cause cliff erosion at Fort Funston, which threatens bank swallow nesting habitats. In another example, human disturbances and off-leash dogs at Ocean Beach have contributed to the decline of western snowy plover populations, which winter at Ocean Beach from mid-July until early May.
Certain pesticides historically caused egg shell thinning for many bird species. The American peregrine falcon, bald eagle and the brown pelican, are vulnerable to some pesticides (especially DDT), which cause eggshells to become thin and break before the chicks hatch. Pesticides banned in the United States, such as DDT, are still present in the food chain. Other pollutants that affect wildlife populations include oil from oil spills and metals and harmful organic substances (such as PCBs) from industrial releases into local waterbodies or soil. These pollutants can affect several organisms in a food chain.
