PALM SPRINGS — Carrying notebooks and GPS devices, researchers walked through the desert of Joshua Tree National Park conducting a scientific survey, methodically scanning the ground for lizards.

Leading the group were ecologists from the University of California, Riverside. But the rest of the researchers were “citizen scientists” — volunteers from Maine, Minnesota and Canada who signed up through the Earthwatch Institute to support a week of scientific research in the desert.

The volunteers have been providing critical support for a long-term research project that aims to assess the impacts of climate change in the national park.

“The main thing is to catalog what we have now so that they’ll know what’s happening in the future,” said Warren Stortroen, a veteran Earthwatch volunteer who has been on 86 research expeditions around the world during the past two decades.

Stortroen, an 82-year-old retired insurance claim center manager from St. Paul, Minn., has joined research outings in places ranging from Australia to South Africa. This was his first time assisting scientists in the Mojave Desert.

“I enjoy the teamwork. I enjoy working with nature,” he said, pausing beside boulders while the group took a break and pulled out their water bottles.

Stortroen was one of 15 Earthwatch volunteers — American, British and Canadian — who helped with the research earlier this month in Joshua Tree National Park. The volunteers split up with park biologists and UC scientists to conduct surveys of plants, count birds and record the numbers of lizards and other reptiles.

The researchers also counted animals such as scorpions and pocket mice that fell into “pitfall traps” — plastic buckets hidden in holes in the ground so that wandering creatures fall in during the night.

Scientists with the national park and UC Riverside began their project last year to track the effects of climate change in Joshua Tree. They have been carrying out surveys on 27 plots that were selected in the park, each one of them a quadrant of about 22 acres.

Joshua Tree National Park stretches from the low-lying and hotter Sonoran Desert to the cooler and higher Mojave Desert, and biologists expect to see significant changes in the vegetation and animal habitats as the climate warms in the coming decades.

Some changes have already been documented. As average temperatures have grown hotter, scientists have found that Joshua trees are gradually dying out in parts of the national park. The knee-high young trees that normally would sprout have largely vanished from some areas, and the remaining mature trees are slowly dying.

Some scientists have estimated that if global temperatures continue to warm as predicted due to rising levels of greenhouse gases, Joshua trees could vanish from up to 90% of their range in the park by the end of the century.

Researchers have found that some types of trees and shrubs have been withering at lower elevations while flourishing at higher elevations. Other plants, such as California junipers and pinyon pines, have been dying in parts of the desert.

Some lizards and insects also have been disappearing from areas where they once thrived, and populations of birds have shifted to higher elevations as the climate has grown hotter and drier. In one area of Joshua Tree National Park, researchers have found large numbers of dead desert tortoises during the severe drought.

To carry out surveys, it helps for the scientists to have a large group of people participating. In each plot, the researchers divide up the area and examine the vegetation by laying out measuring tape and writing down details about the plants they see. They also walk through the plots in formation, marking down the species of reptiles they find.

Cameron Barrows, a research ecologist with the UC Riverside Center for Conservation Biology, said the volunteers are providing important help.

“We couldn’t do this without them,” Barrows said. “It’s important to have lots of eyes when we do these kinds of projects.”

As Barrows led the group across the patch of desert, the volunteers quietly searched for signs of movement on the ground and under the bushes.

“Lizard!” shouted Jane Hamilton, a volunteer from Toronto. She raised an arm so that the scientists could come identify it.

Barrows said it was a zebra-tailed lizard, and he copied it down in his notebook.

Michelle Murphy-Mariscal, another researcher from UC Riverside, said they had found five species of lizards in this plot so far. “That’s great,” she told the group.

Hamilton, a teacher, said she was thrilled to be contributing to science.

“We get really good training in the field before we start so that you feel confident that you’re able to make a contribution,” she said.

In another plot that morning, one group of volunteers helped document more than 40 species of plants, said James Heintz, a researcher with the Great Basin Institute.

“These guys are working super hard, and we’re getting a lot of work done,” Heintz said. “It’s going to paint a really, really clear picture of what’s going on.”

Barrows said that as the researchers return to plots over the coming years, they will be able to see how plants and animals respond to global warming.

“What we’re trying to do right now is create a baseline of animals and plants that will enable us to look in the future years to say, ‘These are changing, the numbers are either increasing or decreasing,'” Barrows said. “We want to be able to identify areas that are really important for protecting these species and make sure that the park is able to identify those as well and protect them.”

The Mojave Desert Land Trust and the Wildlands Conservancy, which protect some wilderness areas near the national park, are also participating in the study.

Barrows and his colleagues plan to eventually publish the results of their research.

Barrows said he has been noticing some changes in the desert lately. He has been seeing very few of two types of lizards — chuckwallas and desert horned lizards — in some of the flat, low-lying areas of the park where he used to see them regularly just a few years ago.

When he spotted one desert horned lizard, Barrows called to the others and picked up the spiky-skinned reptile while they crowded around taking photos.

While the group walked in formation among the creosote bushes, Hamilton suddenly exclaimed: “tortoise!”

The reptile sat motionless in the shade of a yucca.

Murphy-Mariscal was so pleased with the find that the she broke into a celebratory jig. She called it her “tortoise dance.”

Researchers seeking volunteers

Scientists with the UC Riverside Center for Conservation Biology are seeking volunteers to help with research in Joshua Tree National Park on Fridays during the month of April. Those who are interested can contact Cameron Barrows at


Source: ‘Citizen scientists’ help study desert climate change

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