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Tulk elk herd
A herd of tule elk, found only in California, roam a meadow. UC Davis and the state Department of Fish and Wildlife are partnering to learn more about where the tule elk go, and how many there are. (Jennifer L. Brazeal/San Luis National Wildlife Refuge)

Scientists Glean Data About Native Tule Elk from the Humblest of DNA Samples

By Kat Kerlin on November 23, 2016

Sometimes the simplest “technologies” turn out to be the most useful.

When UC Davis scientists set out this fall to study the gene flow of tule elk, they wanted to measure directly at the level of the gene itself. So they went to the ground level. Literally. 

Researchers will be scouring the grounds of Lake and Colusa counties in search of elk poop as part of a multi-year project with the California Department of Fish and Wildlife to study tule elk herds there. Scientists from the UC Davis School of Veterinary Medicine will then analyze the fecal pellets for genetic data. 

The genetic survey will help scientists develop a map of tule elk’s potential range in the region. The work will show how and if genes move across the landscape, identify if and where there are barriers to elk migration, and help give conservation planners a clearer idea of where to focus their efforts.

In the long run, the research could inform efforts to prevent the transmission of diseases like Tuberculosis and Brucella between livestock and wild elk herds.

A Game Changer for Big Game?

Extracting DNA from fecal pellets to estimate wildlife abundance may not be a breakthrough in the genetics world. But recognition of its merit and gradual improvements in the technique have steadily increased over the past decade. And what it lacks in whiz bang, it makes up for in precision.

“It’s simply the only way to get decent estimates in places you can’t view from the air,” said Ben Sacks, director of the UC Davis School of Veterinary Medicine’s Mammalian Ecology and Conservation Unit within the Veterinary Genetics Laboratory, where the pellets will be analyzed.

Aerial surveys typically miss seeing elk, deer and other wildlife hiding in forested areas.  Capture-and-collar techniques can be expensive, invasive and only represent a small sampling of the population. But fecal pellet analysis can cover a much broader range of the population safely, non-invasively and effectively.

This study will be the first application of the technique on free-ranging tule elk.

Tule Elk Part of State Heritage

Why all this fuss for a subspecies of elk?

California is home to Rocky Mountain, Roosevelt and tule elk, all of which are big game animals. The state is required to provide sound population estimates for hunting and conservation considerations.

But it’s more than that. 

“You can’t just say an elk is an elk,” Sacks said.

Simply said, tule elk are special. Found nowhere else in the world, they are uniquely adapted to California’s landscape and climate, and are part of the state’s natural heritage.

From Half A Million To A Handful

Less than 200 years ago, roughly half a million tule elk roamed across central and coastal California. But these animals, which can weigh up to 800 pounds, were heavily hunted following the Gold Rush. By the 1870s, they were thought to be extinct until a few were found on a private ranch in Kern County. Their numbers have since rebounded to about 5,000 individuals in 22 distinct herds across the state.

But while their population comeback is a conservation success story, their genetic diversity still flounders due to the bottleneck of the late 1800s, and inbreeding accelerates the problem. Most of the tule elk’s historic range was converted to crops, cattle grazing and urban development. They now exist in a fragmented landscape.

Ultimately, this study aims to provide a clearer picture of the statewide connectivity of all elk in California.

“For example, we’ve never looked at where Rocky Mountain elk have been introduced near tule elk,” Sacks said. “The state needs to know what subspecies they’re dealing with, if they interbreed, and to what extent.”

Kat Kerlin covers the environment for Strategic Communications.

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