Renewed Hope for the Recovery of a Rare Butterfly in Southern CA
The recovery effort for the critically endangered Quino checkerspot butterfly (Euphydryas editha quino) shows encouraging signs of success. As a native pollinator, the checkerspots survival is crucial to maintaining healthy coastal sage scrub ecosystems in San Diego County.
The Quino’s ongoing recovery originated from a focused effort by CBI and partners. We teamed up with US Fish and Wildlife Service (USFWS), San Diego National Wildlife Refuge, San Diego Zoo, San Diego State University, Creekside Center for Earth Observation, Earth Discovery Institute, and Recon Environmental Inc, in the recovery of the endangered butterfly in San Diego County. CBI’s Spring Strahm coordinated the team of biologists to support the release of over 1,400 larvae within the butterfly’s native range in the San Diego National Wildlife Refuge.
Historically, the Quino checkerspots were one of the most commonly seen butterflies in Southern California, but nowadays they are rarely observed in high numbers. The species was federally listed as endangered in 1997, due to a loss of suitable habitat resulting from urban development, invasive weeds, climate change, and fire.
Given the degree of habitat fragmentation in the area, these butterflies may not be able to reach new suitable habitat patches on their own, making captive release programs an important management tool in the recovery effort.
This recovery effort marks the first time ever for the introduction of
captive-reared Quino into the wild.
While Quino checkerspots have been raised in captivity before, our endeavor marked the first time ever that captive-reared Quino were introduced into the wild to boost wild population numbers. The team hoped to reestablish one or more of the decimated Quino populations, facilitating movement of the newly settled populations to spread to nearby habitat patches and improve connectivity. Additionally, we sought to improve captive breeding protocols and develop an effective release strategy.
Once the team at San Diego Zoo’s Butterfly Conservation Lab successfully raised larvae in captivity, it was time to release some of them into the wild. The team chose locations with abundant populations of the dwarf plantain (Plantago erecta), the butterfly’s preferred plant. It was also important to target areas predicted to undergo minimal alterations due to climate change based on climatic water deficit data (an estimate of drought stress on soils and plants).
Over 1,500 Quino larvae were released in the butterfly's native range
within San Diego National Wildlife Refuge.
Specially-designed release pods for Quino larvae. Photos by: Spring Strahm.
In December 2016, the team released 742 Quino larvae at the San Diego National Wildlife Refuge in historical Quino habitat. Larvae were placed inside specially designed release pods developed by the San Diego Zoo. Each pod was constructed using a sphere of wire mesh (a repurposed Christmas ornament) to protect the larvae from large predators (such as birds), a small interior pot to support the larvae, and a plastic disc to shield larvae from intense rain. Larvae (measuring 4-6mm at the time) were placed inside these pods while they were still in diapause (a life stage similar to hibernation), with the hope that natural cues would wake them up under ideal conditions.
Pods were wired inside shrubs to keep them shaded and near areas likely to contain the host plant. Quino larvae began emerging from release pods in early January 2017 and grew to 1cm. Following this success, an additional 771 larvae were released in pods mid-January 2017, bringing the grand total released to 1,513 Quino larvae.
The San Diego Union Tribune interviewed Paige Howorth, associate curator of invertebrates at the San Diego Zoo. She said, “Observing more than 35 butterflies flying in one day on the reintroduction site is extraordinary. It’s a welcome measure of hope, after years of drought and uncertainty for this species.”
There is definitely more work to be done, and we anticipate building on recent success with partners in reestablishing the Quino checkerspot butterfly population in San Diego County. Full reestablishment of the population requires multiple releases of the Quino checkerspot butterfly. Expanding the effort to other nearby habitat patches is an important next step in developing a resilient population. To learn more about the Quino recovery effort, you can check out the featured story from the USFWS and view CBI’s recorded webinar on the project.