Palos Verdes blue butterflies were known to occur throughout the coastal slope of the topographically diverse Palos Verdes peninsula in Los Angeles County, California.
The distribution of the population of the Palos Verdes blue butterfly is directly related to that of the abundance of the larval host plant (the locoweed) that allow for the population growth. The host plant is readily available as far North as Santa Barbara. Up until 1994, the population was only known to exist in one area which was cleared for a housing project. However a butterfly population was observed at the department of defense facility in San Pedro and its surroundings.
The Palos Verdes blue butterfly was once considered extinct, and then rediscovered at a site outside its former known range on the inland, more eastern, slope of the peninsula. This is why “reintroduction” sites were implemented on this map. A relatively small but stable population of the Palos Verdes butterfly has been observed at the DFSP San Pedro/Navy housing site. Furthermore, the population of the Palos Verdes blue butterfly at the Chandler Preserve will be monitored for the next few years to conclude if the reintroduction was successful.
This image illustrates the Historical distribution and reintroduction sites of the Palos Verdes blue butterfly (Glaucopsyche lygdamus palosverdesensis) in Los Angeles County, California. Two attempts at introduction have occurred in the past: Trump National Golf Course where Palos Verdes blue butterflies were released in 2009, and Deane Dana Friendship Community Regional County Park in 2009 and 2010. 2013 studies of the Palos Verdes blue butterfly population shows that it was not successful. However, in Trump National Golf Course, the population, according to studies, has been successful.