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Joshua Tree Citizen Science Sheds Light on Climate Change

Lizard's eye view of a pit trap
Lizard's eye view of a humane pit trap used to count wildlife | Photo: Joshua Tree National Park

Nearly thirty years since the term "citizen science" was first used to describe a 1989 project to engage non-scientists in a study of acid rain, many in the sciences have come to a mutual understanding that this type of engagement and outreach has tremendous benefits for public understanding of science; its value as an educational tool can't possibly be overstated.

Still, some researchers still question the value of citizen science for scientific knowledge building. They are dubious that citizen scientists can serve as competent agents for high quality data collection. But recent citizen science-based research in Southern California's Mojave and Sonoran deserts show just how scientifically valuable citizens can indeed be.

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UC Riverside conservation biologist Cameron W. Barrows, like most conservation biologists, wanted to understand how climate change was going to affect biodiversity in the long run. That means collecting data in the same place, month after month, year after year, and sometimes decade after decade, to understand the long-term trends in wildlife communities. Only with such a long-term dataset can researchers parse out the differences between climate and weather, and between climate and all the other stressors that humans inflict onto the natural world. But that kind of research requires quite a lot of money as well as other forms of non-financial support from scientific and academic institutions, and that in a political climate where scientific funding, especially for understanding climate change, is decreasing or even non-existent.

To deal with this problem, Barrows came up with two solutions.

The first was to focus on a particular swath of the desert around Joshua Tree National Park where the Sonoran Desert meets the Mojave. Despite both being classified as deserts, the two regions have different characteristics. The Sonoran Desert, which stretches up to southern California and southwestern Arizona from Mexico for example, sits at low elevation, between 1,000 and 3,000 feet above sea level in Joshua Tree National Park. (And to below sea level south of the Park.) The Mojave Desert, which stretches from Southern California east into Nevada and parts of Arizona and Utah, is higher up, from 3,000 to 5,000 feet and change above sea level in the Park. Looking at regions of ecosystem transition is a more efficient way of understanding the effects of climate change more broadly.

The second solution addressed the financial issue. "We'd have to be doing this for many years and possibly decades. To find a consistent group of scientists we could pay to do something like that was not reasonable," says Barrows. But by using fewer professional scientists and more citizen scientists, Barrows could ensure a sustainable method for data collection that would allow him to build a dataset over multiple years and decades.

"A lot of scientists have raised concerns about having people who aren't trained," he says. "We were willing to take that chance, but we wanted to test it." So Barrows and his team first had a pair of trained field biologists conduct reptile surveys of a handful of pre-designated plots within the park. Then Barrows returned to the same plots a couple weeks later, accompanied by a team of up to eight citizen scientists.

The professional scientists and the citizen scientists followed the same steps. Surveyors walked in parallel lines, separated by 5 to 10 meters, and took note of every reptile they saw, including information about its age when that was possible. At each location they found a critter, they used a handheld GPS to mark its location.

Prior to the data collection, the citizen scientists were given a 10-15 minute briefing on safety and data collection protocols. For some of the volunteers, this was the first time ever seeing a desert, let alone conducting a wildlife survey. So whenever they found a reptile, they just had to shout "I've got a lizard," or "I found a snake," and Barrows himself would hurry over to confirm the identification to species. The volunteers who spent more than a single day in the field eventually become proficient enough that Barrows could relax a bit. "I got a lot less exercise the more times [the volunteers] had been on a survey," he recalls.

And not only did the citizen scientists stack up to the pros, they actually outperformed them. "Invariably we [recorded] two to three times as many individuals, and at least twice as many species," when he surveyed with citizen scientists, Barrows says. "That was pretty striking."

It wasn't that the two trained biologists were poor observers. It was that eight citizen scientists possess twelve additional eyes. For Barrows, the benefits of citizen science can't be any clearer. "It's a great way to get people understanding how science works. It gets them invested not only in conservation, but in ensuring that good science happens," he says. "We are convinced now that we're getting much better data when we're using citizen scientists than when we're not. It's a win-win."

Horned lizard being measured at Joshua Tree NP
Horned lizard being measured at Joshua Tree NP | Photo: Joshua Tree National Park

The cautionary note is that the volunteers can't simply sit through a fifteen-minute training session and be sent off on their own. What Barrows believes, and this is supported by other studies of citizen science projects, is that citizen scientists can deliver high quality data when they work side by side with the professionals.

It's not just that Barrows himself supervised, acting as the last line of defense when it came to identifying the species. He thinks that by creating a true collaboration, the volunteers felt that their contributions were more valuable, boosting their energy and enthusiasm for participating on a voluntary basis.

As for the science itself, he recorded more side-blotched lizards and western whiptails at higher elevations than lower, while zebra-tailed lizards – along with plenty of juveniles – were restricted to the lower Sonoran Desert plots. Common chuckwallas were found in the middle, absent from both the lowest and highest plots, suggesting that their movements over time could provide a useful metric for assessing climate-related changes. And western fence lizards were only found at the highest elevation sites, with juveniles isolated not just to the highest but also to those plots farthest west.

Chuckwalla at Joshua Tree
Chuckwalla at Joshua Tree | Photo: Geir Edland, some rights reserved

"This is a pattern we would expect with species regionally at risk to the effects of climate change," the researchers wrote in the journal Biological Conservation. Indeed, the absence of side-blotched lizards, western whiptails, and chuckwallas at the lowest points may already be the result of a warmer, more arid climate; chuckwallas were once common in the lower-elevation Sonoran Desert.

The only way to preserve species under the specter of climate change is to record long-term trends in wild plant and animal communities so that particular sites of high conservation value can be identified. Citizen science offers an equally sustainable and rigorous avenue for doing so, with the critical bonus of improving scientific and ecological literacy.

Banner: volunteers chart vegetation at Joshua Tree to help measure climate change impacts. Photo: Joshua Tree National Park

For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.

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