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US Fish & Wildlife Service FieldNotes
CARLSBAD: The Return of California's El Segundo Blue Butterfly
Region 8, July 18, 2007

Stephanie Weagley, Carlsbad Fish and Wildlife Office

In June 2007, the El Segundo blue butterfly was spotted fluttering among beachgoers at two Los Angeles county beaches –places where it had been absent from the public’s eye for decades.  The natural resurgence of the butterfly along the coastal bluffs in Redondo Beach and Torrance is something wildlife experts never expected.


The El Segundo blue butterfly, a federally endangered species, can be found only along the southeastern shores of Santa Monica Bay.  Known populations exist on coastal dune habitat located adjacent to the Los Angeles International Airport, and on property located at Chevron Refinery in El Segundo and at Malaga Cove in Torrance.  The largest butterfly population inhabits the Airport dunes.


The reappearance of the butterfly at Redondo Beach and Torrance has been a surprise in many ways.  First of all, previous scientific studies indicated the butterfly was relatively sedentary and typically did not fly distances further than 200 feet.  With these new sightings however, this butterfly is challenging that scientific notion.  At its newfound location, the El Segundo blue most likely flew 1,000 feet away from its nearest known habitat, thereby demonstrating that its dispersal capabilities are greater than once thought.  Furthermore, this location may indicate that the species can naturally re-colonize sites containing the native coastal dune vegetation it depends upon in order to flourish and survive.


Native habitat restoration has definitely played a key role in this butterfly’s return.  Since 2003, native vegetation re-introduction efforts along the coastal bluffs of Redondo Beach and Torrance have been conducted by residents, conservationists, government officials and representatives from two nonprofit groups, the Urban Wildlands Group and the Los Conservation Corps Science, Education and Adventure Lab program.  The removal of nonnative vegetation and the restoration of native scrub plants, such as coast buckwheat, California sunflower, deer weed, prickly pear cactus, and lupines continue to this day.  


The life cycle of the El Segundo blue butterfly is intimately tied to coast buckwheat as each of its four life stages (egg, larva, pupa and adult) depend on this plant.


With a loss of approximately 90 percent of the butterfly’s historic dune habitat, habitat available for conservation and restoration is limited.  Although no significant loss of occupied habitat has occurred since the species was listed in 1976, the El Segundo blue butterfly exists only at fragmented sites with small population numbers.


Habitat modification and destruction remain a threat for the butterfly.  For example, direct competition with vegetation that is not native to the coastal dunes ecosystem, such as acacia, certain species of iceplant, and non-native grasses threatens the persistence of coast buckwheat. Therefore, even habitat which is not threatened directly by development is still likely to become degraded and not support the El Segundo blue butterfly if not actively managed.  Thus, while progress has been made at reducing the threat of habitat loss and modification, these factors still threaten the butterfly’s survival and recovery. 


The El Segundo blue butterfly was federally listed as an endangered species in 1976 under the Endangered Species Act.  At the time of listing, habitat destruction and inadequacy of existing regulatory mechanisms were identified as threats to the species.  The recovery plan, which was issued in 1998, identified additional threats to the species from habitat modification and over-utilization for commercial purposes. 


The known population sites for the El Segundo butterfly are off-limits to the public.  Although protection and management activities have been implemented with varying degrees of intensity over the past decade of varying degrees, none have long-term commitment or funding for management, which means no occupied sites have permanent protection. The butterfly remains in danger of extinction due to habitat loss and modification, limited range, small population numbers and a lack of adequate protections.


With the resurgence of the El Segundo blue butterfly at two Los Angeles county beaches, there is hope that through continuous cooperative conservation efforts, this tiny butterfly can co-exist with the human race and fully recover from its current endangered species status.


Contact Info: Scott Flaherty, , Scott_Flaherty@fws.gov