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Species Spotlight: Work since El Segundo Blue Butterfly listing has led to population revival

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Species Spotlight ButterflyThe El Segundo Blue Butterfly relies on seacliff buckwheat for survivalThe El Segundo Blue Butterfly is endemic to the coastal dunes of Los Angeles County in California. The sandy dunes and surrounding ecosystem are essential to the butterfly’s survival.

Extensive development in this habitat put the El Segundo Blue Butterfly population in danger of extinction. In 1976, the butterfly was listed as endangered under the Endangered Species Act, prompting the preservation of the last remaining dunes of its habitat.

Since then, through protection and restoration of the butterfly’s habitat, the population is growing. The tiny butterflies have even traveled to newly restored dunes, a feat that scientists never expected that will make the population more resilient as it continues to rebound.

Species Spotlight, a case study series examining the challenges and opportunities in species conservation, is part of the Western Governors' Species Conservation and Endangered Species Act Initiative, the Chairman's Initiative of Wyoming Gov. Matt Mead.

CONSERVATION ACTIONS

The major threat to El Segundo Blue Butterfly survival is habitat loss and degradation. Throughout its lifecycle, the butterfly relies on a single plant, seacliff buckwheat, which prefers sandy, unstable coastal dunes. This habitat, found only in Los Angeles County, was small to start with and shrank further as the city grew and coastlines were developed.

At the time the butterfly was listed, only two populations were known to exist -- one on undeveloped land owned by the Los Angeles Airport and another on less than two acres of dunes at a Chevron refinery.The listing put a halt to airport expansion plans, but major restoration efforts were also needed. The City of Los Angeles worked with the airport to establish a 200-acre habitat restoration area while Chevron has actively managed its 2 acres of seacliff buckwheat habitat since the 1980s.

Restoration includes ongoing work to keep invasive species from outcompeting seacliff buckwheat. Nonprofits, such as Urban Wildlands Group, have worked with residents near the existing butterfly populations to voluntarily restore the native dune ecosystem on their lands.

RESULTS

The butterfly population has thrived with habitat protection and management. The airport dunes have supported peak summer population of as many as 143,000 butterflies in the past decade and the Chevron population is also growing.

In the summer of 2007, the El Segundo Blue Butterfly was spotted at two Los Angeles beaches, indicating that the species had naturally dispersed beyond its previously known populations. This is a major success for the species, which scientists initially doubted would be able to recolonize its former range. As private landowners and nonprofit groups continue to restore the native dune ecosystem, the butterfly may be able to spread along the coast to inhabit more of its former range.

At the moment there is no effort to delist the butterfly because it remains conservation-dependent, although that could change if it continues to naturally recolonize its former range.

More in the Species Spotlight series: 

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