Drought Offers Insight Into How Species Will Fare in a Warming World
Scientists should take advantage of extreme weather events today to collect the data that could help save species from extinction in the future.
That’s the message of a new paper, published in PLOS One, that used the California drought to help understand how climate change will affect the habitats of an endangered species called the blunt-nosed leopard lizard.
The paper emerged from an ongoing study into the leopard lizard, which lives in California’s San Joaquin Desert. The recent drought hit the species particularly hard, and the lizards stopped breeding in many parts of their range, probably owing to a lack of water, protective vegetation, and food. Leopard lizards have fairly short generations of just a few years, so biologists fear the drought may have a negative impact on their long-term prospects.
“I’m a little worried,” said Michael Westphal, an ecologist with the United States Bureau of Land Management and the lead author of the paper. “If a drought like this were to extend for five years, I could see entire populations getting knocked out.”
Although Westphal was already observing the lack of reproduction in 2014, the cause was not clear until another of the paper’s authors, University of California, Santa Cruz, graduate student Joseph Stewart, overlaid maps of where the lizards weren’t breeding with rainfall data he had collected for the region. “We said, ‘Holy cow, it appears there’s this correlation between rainfall and reproduction,’ ” Westphal said.
That’s when the third author of the paper, UC Santa Cruz ecology professor Barry Sinervo, added even more perspective. His previous studies into lizards confirmed the relationship between lack of rain and lack of breeding.
At that time, a lightbulb went off in Westphal’s head. He realized that he had a broad range of experts, also including researchers from the California Department of Fish and Wildlife and The Nature Conservancy, who could conduct a rapid examination of the leopard lizard’s habitat during the drought. The goal: See how the ongoing extreme event could help them predict how the habitat—and the lizard—would be affected by future events.
“We all called each other up,” Westphal said. “We’ve got the people and the skills. We’ve already formed these partnerships. We all went out, and we made it happen.”
The results of their survey revealed several portions of the habitat that could provide “habitat refuges” for the lizards—safe places where they could survive—as well as areas where they probably wouldn’t fare as well. Westphal said the second revelation offers the opportunity to consider management actions that can improve those habitats before climate change makes them inhospitable. No decisions have been made, but the agencies in charge of conservation of blunt-nosed leopard lizards are “certainly talking about it,” Westphal said.
The researchers said they hope the paper can be a model for other researchers. “We want to encourage people to put themselves in the mode to mobilize when extreme events occur,” Westphal said. “Instead of saying, ‘This drought sucks,’ see the silver lining and get on it as fast as you can. There are important data to be harvested here. When you’re talking about climate change, you can never have too much data.”
The opportunities exist. “Right now, Arizona is in the midst of an intense drought, and we are seeing local population extinctions here, as well as in the Mojave Desert,” said Sinervo. He called the paper “an eye-opener for me for the future.”
As for the blunt-nosed leopard lizard, its future is in question. Later in the year, the researchers will conduct a study to compare the animals’ genetic variation before and after the drought. They’ll also see if births have increased now that rainfall has increased.
They’ll continue looking at the upcoming droughts that climate-change models predict will occur with greater frequency and severity. “If we have another drought like [California’s] but twice as long, we’re going to be worried about other things than lizards,” Westphal said.