Recovery plan set for island marble butterfly

But now the U.S. Fish and Wildlife Service has come up with a plan to help the species recover to the point that it no longer requires the endangered listing.

The plan calls for spending $25.5 million — in 2020 dollars — over 28 years.

According to the Fish and Wildlife Service's Recovery Implementation Strategy, there has been no update to the population size estimate since 2006 when there was thought to be 300 to 500 of the species.

Still, that report says there has been a consistent and substantial decline in the number of adults observed since monitoring began in 2004.

The service's Draft Recovery Plan says that a major cause of the island marble butterfly's decline is the loss of suitable habitat.

Other causes are the threats from predators and vulnerabilities associated with the species' small population size, said the plan.

Because the lack of suitable habitat is such a big issue, the plan is to spend a good portion of the $25.5 million to manage and protect such habitat.

Among the eight recovery actions listed in the plan:

• $10.4 million would be spent to conserve and manage suitable habitat on sites that have long-term conservation commitments.

• $4.8 million would go to protecting the American Camp population and its habitat, which includes 812 acres of what is designated as critical habitat on the south end of San Juan Island.

• $4.4 million would be spent on identifying three to five other areas of suitable habitat — or what the service calls core occurrence complexes — on San Juan Island and beyond. 

• $2.1 million would go to establish and expand diverse habitat used by the butterfly, such as coastal lagoons, grasslands and sand dunes.

These four recovery actions are given the highest priority in the plan, meaning it has been determined that they must be taken to prevent extinction or to keep the species from declining irreversibly.

By devoting so much attention to the habitat of the butterfly, the hope is threefold — to improve resiliency by increasing the population and making it better able to withstand random events; to increase redundancy by creating more habitat throughout the butterfly's historic range; improve the ecological diversity and preserve the genetic diversity of the species to ensure its adaptive potential.

The historic range of the marble island butterfly was from the southeastern coast of Vancouver Island north to Nanaimo, though the last known specimen in Canada was collected in 1908.

The species was rediscovered in 1998 on San Juan Island, and in 2006 five populations were identified on San Juan and Lopez islands.

By 2012, the butterfly was found only at American Camp, with a few larvae detected on Lopez Island.

The U.S. Fish and Wildlife Service is taking public comment on the draft recovery plan.

It will accept information at any time, but for comments to be considered for the plan they must be received by Aug. 8.

Comments can be mailed to Tara Callaway, U.S. Fish and Wildlife Service, 500 Desmond Dr. SE, Lacey, WA, 98503, or emailed to WFWO_LR@fws.gov with “Draft Island Marble Butterfly Recovery Plan Comments” in the subject line.