The Elusive “VELB” Seen at Mitigation Sites
Endangered Valley Elderberry Longhorn Beetles Spotted
Late spring and early summer 2010 marked a significant milestone for endangered species protection. While monitoring elderberry mitigation sites, our biologist, Michelle Boercker encountered several valley elderberry longhorn beetles (“VELB”). A male was sighted on May 18th, a female on May 20th, and a male and two females on June 2nd.
VELB sightings are exceedingly rare; many biology professionals only see a live specimen in a lab during their entire career.
“I felt like I had won the lottery,” recalls Michelle. “The odds that I would actually see one were so low. In general, the USFWS recommends that VELB counting take place between February 15 and June 30. That is when flight period is most likely to occur. We at River Partners were extremely lucky to hit the right time period when they appeared at these particular sites by the Feather River.”
According to Helen Swagerty, River Partners’ Senior Restoration Biologist, River Partners has been monitoring VELB for at least 10 years. The largest monitoring effort took place in 2004. River Partners received a grant to survey 10% of the 70,000 elderberry shrubs planted within the Sacramento River National Wildlife Refuge. “In all that time and among thousands of elderberry plants, we’ve only seen a live beetle in the field once – in 2002 at a mitigation site on the Sacramento River. That’s what makes the May-June sightings so phenomenal.”
The VELB is a medium-sized (about 2 cm in body length) brightly colored beetle. The species spends most of its life inside an elderberry shrub. Its larvae thrive on the woody pulp. When they reach maturity after 1-2 years, the adults emerge from the elderberry stems. Typically these “exit” holes are the only evidence of VELB presence on an elderberry plant (since actually seeing and counting them is practically impossible).
The VELB (Desmocerus californicus dimorphus) is a federally-listed threatened species. Once part of the Central Valley’s robust riparian corridor, its numbers rapidly declined with the clearing of habitat along valley rivers. The beetle depends solely on the elderberry plant (Sambucus mexicana), which grows in valley riparian zones, for its entire life cycle. River Partners includes the elderberry shrub as part of its restoration designs wherever we are able. In addition to helping the VELB, the shrub produces distinctive white flowers that attract pollinators and its fruit is a food source for other wildlife. Sometimes, in order to secure permits for our work, we are required to eliminate this plant species from our restoration plans.
However, large projects like the Bear River Set-back levee restoration site, the O’Connor Lakes restoration site, as well as our work on the Sacramento River National Wildlife Refuge, have allowed us to bring back elderberry shrubs to new habitat areas and help the recovery efforts of the VELB.
The mitigation sites that RP biologist Michelle Boercker was monitoring were developed as an endangered species solution for the impacts from the setback levee construction work on the Feather River. River Partners assisted the Three Rivers Levee Improvement Authority and Levee District 1 by transplanting more than 120 elderberry shrubs that grew in the footprint of new setback levee construction. Thanks to the cooperation of the USFWS, who accepted River Partners’ recommendation to plant multiple stems per basin (as opposed to one stem per basin), the transplanted shrubs have succeeded in their new locations. More than exit holes, River Partners has observed live VELB presence on these transplanted shrubs.
“The success of these mitigation areas shows that dialogue and collaboration among wildlife and flood control agencies can produce solutions that help endangered species and public safety,” says John Carlon, River Partners president. “The USFWS recovery plan is working and I think we’re on track towards the recovery of the VELB.”
To view Michelle Boercker’s field notes and photos, download the PDF.