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The Escondido Creek team participating in the Goldspotted Oak Borer survey

Goldspotted Oak Borer Survey at Keithley Preserve.

Featured Image courtesy of Juan Troncoso. Words by Juan Troncoso.

The Goldspotted Oak Borer (GSOB) is a beetle native to Southeastern Arizona. It is suspected that it was introduced into San Diego County via firewood. The beetle was first detected San Diego County by the California Department of Food and Agriculture in 2004 and in 2008 it was link to elevated mortality of oaks. In our landscape, oaks are a keystone species and many animals depend on them for food and shelter.

In an effort to understand the impacts of GSOB and to create a management plan for Keithley Preserve, the Conservancy was invited to join a research project with Dr. Marc Mayes (Peregrine Environmental Imaging, L.L.C. and UC-Santa Barbara) and Andrea R. Hefty, PhD (U.S. Forest Service). The project aims to “test the use of drone imaging for (a) identifying gradations of infestation (severe/brood trees priority) and (b) quantifying site-scale canopy condition as a pest management tool.”

For the project the Conservancy recruited five interns who over the spring semester diligently walked the oak woodlands at Keithley Preserve and surveyed all oaks with diameters greater than 10 inches. During the surveys our interns and staff were looking for number of exit holes, woodpecker foraging, bleeding spots and canopy thinning.

At the end of the survey, Conservancy staff (including interns), Dr. Marc Mayes and Dr. Andrea R. Hefty went out to the field, collected more canopy thinning data, and did some initial drone flights to assess the condition of the oak woodland.

So, what’s next? Late in July, the group will get together to work on a second location within the preserve, and do multi-spectral imaging flights overhead. Then the Conservancy staff will create and execute a management plan based on the data collected to preserve the oak woodland in Keithley.

An overhead drone photo of the survey team standing on a dirt road surrounded by coastal sage scrub. They are between two white work pick-up trucks facing opposite directions

Drone photo credit: Taken by Dr. Marc Mayes (Peregrine Environmental, L.L.C. and UC-Santa Barbara)

A close up image of a Goldspotted Oak Borer beetle
A white drone taking off over coastal sage scrub