The critical habitats makes the butterfly extinct
The California Endangered Species Act does not allow listing of insects, so despite its precarious status, Lange’s metalmark has no protection under state legislation. The California Department of Fish and Game includes this butterfly on its Special Animals list.
Through intentional disturbance, efforts at encouraging the host plant have proven fruitful and the butterfly’s numbers seems to be on the rise. Habitat improvement activities have included dune restoration, hand-clearing nonnative plant species, planting buckwheat seedlings, and restricting public access to avoid trampling and fire.
In the late 1990s, the butterfly population was around 2000 adults. A fire that burned about 40 percent of the reserve in 2000 devastated the population. More recent counts have recorded less than 450 butterflies. Reserve staff have an active program of replanting the naked stemmed buckwheat host plant to augment natural recolonization across the burned areas and support recovery of the butterfly population.
Lange’s metalmark was designated as a federal endangered species on June 1, 1976 (Federal Register 41:22044). A draft of a recovery plan for the Antioch dunes ecosystem was submitted on April 25, 1984. This recovery plan—Revised recovery plan for three endangered species endemic to Antioch Dunes, California—was never finalized and is out of date.
Recovery Plan (ESA): Revised recovery plan for three endangered species endemic to Antioch Dunes, California 25/04/84
Profile prepared by Scott Hoffman Black and Mace Vaughan, The Xerces Society for Invertebrate Conservation
Lange’s metalmark is currently found only at the Antioch Dunes in Contra Costa County, California. The butterfly has a very close relationship with naked stemmed buckwheat. The eggs are deposited on buckwheat leaves near the leaf petiole and the larvae are known to feed only on this buckwheat. The buckwheat is also an important nectar source for adults, along with Douglas’ ragwort and San Joaquin snakeweed.
Most of the butterfly’s original sand dune habitat has been lost. Stabilization of the remaining dunes is a major threat to Lange’s metalmark because naked stemmed buckwheat requires shifting sands for seed germination. Conservation efforts should revolve around protecting the remaining dunes and ensuring mobile dune systems for the host plant.
Source: The Xerces Society