Biologists are using an innovative technique to determine how many San Joaquin kit foxes are living on a section of the Carrizo Plain earmarked for a large solar project.
Scat dogs have been used over the past two years to survey the Topaz Solar Farm site. These are search dogs that are specifically trained to sniff out and differentiate various kinds of animal droppings.
As a result of the surveys, 153 scat samples have been collected and sent to the Smithsonian Institution in Washington, D.C. DNA analysis of the samples is painting a detailed genetic portrait of the Carrizo kit fox population.
This information will be used as baseline data to determine what effect construction of the sprawling photovoltaic project could have on the endangered kit foxes. First Solar of Tempe, Ariz., has proposed installing solar panels over 4,000 acres at Highway 58 and Bitterwater Road to produce 550 megawatts of power.
“Our goal is that the kit fox population on the project site after construction will be equal to or greater than it is now,” said Alan Bernheimer, First Solar spokesman.
The project is in the crucial permitting phase with construction scheduled to begin later this year. The biological impacts of the project — most notably on the diminutive fox — are one of the main concerns.
Biologist Dan Meade, of the Paso Robles consulting firm Althouse and Meade, heads up the kit fox monitoring effort. He hired the Working Dogs for Conservation Foundation of Three Forks, Mont., to do the scat surveys.
Surveys were done in the late summer or fall of 2009 and 2010. Using a grid pattern, a scat dog ranges ahead of its handler. The dog sits to alert the handler when kit fox scat is found. The droppings are about the size of a person’s little finger, Meade said.
If the scat is eight days old or fresher, it is collected and sent to the Smithsonian Conservation Biology Institution for DNA extraction and analysis. DNA can identify individual foxes, determine the animal’s sex as well as how closely related it is to other foxes in the study area.
After two sampling seasons, preliminary results are in. Of the 153 samples, DNA was extracted from 123. Three were determined to be from a red fox and the remaining 120 were kit fox.
Nineteen individual kit foxes were found in the Topaz Solar Farm area. All but one appeared to permanently occupy the area. The scat of one, a male, was found only once and it is unlikely to live in the study area, Meade said.
Interestingly, the analysis showed a high level of interrelatedness among the foxes. This probably means they are grouped into several large, extended families, wrote Jesus Maldonado, the research geneticist who did the DNA analysis.
It is too early to tell how healthy the kit fox population is, Meade said. Fewer foxes were found in the 2010 survey than in 2009.
This could be due to high levels of mortality in pups, which can be as much as 80 percent. Subsequent surveys will tell biologists more about the foxes’ survival rate and long-term prospects.
“Kit fox scat studies will continue for five years to measure population during project operation,” Bernheimer said.
Meanwhile, First Solar plans to make its project as fox-friendly as possible. Planned steps include fencing around the solar arrays through which foxes can pass but not their main predator, the coyote, and controlling vegetation beneath the solar panel arrays.
“The goal is to allow the foxes into the project site,” Meade said.
The company will also replace any grassland — the foxes’ favorite habitat — lost to the project on a 4-to-1 basis as well as conserve farmland lost to the project at a 1-to-1 ratio, Bernheimer said.
First Solar will soon see if its kit fox mitigation efforts are sufficient. The project is tentatively scheduled for a Planning Commission study session Thursday and a hearing March 24.
Reach David Sneed at 781-7930.