by Sammy Roth, The Desert Sun 1:51 p.m. PDT July 15, 2015
For photo gallery that went with article go to
http://www.desertsun.com/story/news...tree-tracking-tortoises-art-science/30157363/
About halfway up the rocky hill overlooking Dead Sheep Canyon, Shellie Phillips paused.
The radio receiver she held in front of her was beeping steadily, a sign that a desert tortoise called Squirt should be nearby. But Squirt — so named for her habit of peeing in the presence of researchers — was nowhere in sight.
It was 6:30 a.m. on Tuesday, and the sun was rising over the southern end of Joshua Tree National Park. Phillips and her fellow researchers needed to find Squirt before it got too hot, so they could take her to their truck, X-ray her to check for eggs she might be carrying, and then bring her back.They looked around the still-shaded hillside, eyes searching.
"I think she might be in that burrow," Phillips said.
"I don't see her, but that doesn't mean she's not here," lead researcher Jeff Lovich replied.
Squirt had a small radio transmitter affixed to her shell, and it was sending signals to Phillips' receiver. But she and Lovich thought the signals were bouncing around the canyon, misleading them. So they started back down the hill, toward the part of Cottonwood Canyon they'd taken to calling "Dead Sheep Canyon" because of the sheep bones scattered by a certain bush.
Before they got too far, Squirt was spotted, right where they'd been looking for her. Lovich grinned.
"You can see how this is some part science and some part art," he said. "We walked right around her in a circle."
Lovich and Phillips are part of a team from the United States Geological Survey that is tracking desert tortoises near the Coachella Valley. The slow-moving but wide-ranging creatures are listed as "threatened" under the federal Endangered Species Act, and researchers are trying to understand where they're thriving and how quickly they're reproducing — and how California's drought is impacting their odds of survival. On Tuesday morning, that meant traipsing around Cottonwood Canyon, finding the nine tortoises the team had outfitted with radio transmitters and taking X-rays of the females. The researchers have made the trip from Flagstaff, Arizona, every 10 days or so since April, when they first surveyed the area. They've found about 20 tortoises overall.
X-rays revealed no eggs Tuesday, but that was expected — breeding season lasts from April through July. Previous visits had yielded egg-filled scans, including one showing nine potential hatchlings in a tortoise known as Baby.
"If we have enough of them that don't produce eggs, it's possible the population is beginning to decline," Lovich, an ecologist, said.
Baby was active and unafraid on Tuesday, looking around alertly and trying to climb out of the box researchers used to carry her to their truck. Squirt was shy, keeping her head tucked away in her shell. A male tortoise known as Studmeister proudly stood outside his burrow and watched as the team approached, before gamely posing for photos.
Studmeister got his name because the first time the researchers saw him, he was intimately engaged with Baby.
"They have different personalities," said Laura Tennant, one of the researchers. "Sometimes they'll poke their heads out, be vivacious, have fun with you. Sometimes they'll be more reserved."
Another male tortoise is called Stub — short for stubborn, since he often refuses to emerge from his burrow. Josie is named for Josie Grossie, the unfortunate nickname for Drew Barrymore's character in "Never Been Kissed."
Then there's rock-loving Rockette, who was so hesitant to crawl out of her creosote-covered burrow Tuesday that Tennant had to lure her out by spraying water in front of her.
"She should have been named Stubborn No. 2," Tennant said.
The team has made some interesting findings, which could prove valuable to future tortoise protection efforts.
For one thing, the tortoises in Cottonwood Canyon seem to enjoy the rocky hillsides more than the flat desert floor, even though researchers had expected otherwise. The team has a few theories: Maybe predators have a harder time hunting them down in the hills, or maybe the tortoises prefer the shade. It's also possible that males are chasing females uphill, which Phillips described as the group's favorite theory.
The tortoises are certainly slow, but they're better at traversing steep slopes than many people. Lovich described them as having "a low center of gravity and a four-wheel drive."
"They're basically the ultimate climbing machine," he said.
Desert tortoises have also been impacted by the severe drought, Lovich said. His previous research has shown that tortoise survival is tightly coupled with three-year average rainfall — and the state is now suffering from a fourth year of historic dryness.
"If it doesn't rain next winter, my prediction is a lot of these tortoises will die," he said.
Across the Southwest, rising temperatures and epic drought are harming wildlife and plant life — and human-caused climate change is expected to make things worse. Already, higher temperatures are threatening Joshua Tree National Park's iconic, eponymous trees. The drought is also killing much of the vegetation that desert tortoises depend on, leading to die-offs.
The changing climate is only compounding the pressures on species like the desert tortoise, which have already been decimated by decades of expanding development and destruction of habitat.
"Although you think of the tortoises as a really tough desert species that can take anything, the prolonged drought takes its toll," said K.D. Fleming, who works for the Coachella Valley Conservation Commission.
The U.S. Geological Survey team is partnered with the commission, a sister agency of the Coachella Valley Association of Governments. As part of the Coachella Valley Multiple Species Habitat Conservation Plan, the commission works to protect desert tortoises, along with 26 other animal and plant species.
Fleming, the commission's habitat conservation management analyst, applied for $70,000 in state grants to fund the researchers' work. That money covers tortoise monitoring this spring and next spring.
Fleming plans to apply for more money, ideally to test for genetic differences between tortoises north and south of the Interstate 10. Her fear is that the freeway is too significant a barrier for tortoises to cross, which could cause distinct gene pools to form and lead to a decrease in genetic variability. It's a dangerous process known as inbreeding depression.
"We have a lot of questions, but not a lot of answers at this point," Fleming said.
For photo gallery that went with article go to
http://www.desertsun.com/story/news...tree-tracking-tortoises-art-science/30157363/
About halfway up the rocky hill overlooking Dead Sheep Canyon, Shellie Phillips paused.
The radio receiver she held in front of her was beeping steadily, a sign that a desert tortoise called Squirt should be nearby. But Squirt — so named for her habit of peeing in the presence of researchers — was nowhere in sight.
It was 6:30 a.m. on Tuesday, and the sun was rising over the southern end of Joshua Tree National Park. Phillips and her fellow researchers needed to find Squirt before it got too hot, so they could take her to their truck, X-ray her to check for eggs she might be carrying, and then bring her back.They looked around the still-shaded hillside, eyes searching.
"I think she might be in that burrow," Phillips said.
"I don't see her, but that doesn't mean she's not here," lead researcher Jeff Lovich replied.
Squirt had a small radio transmitter affixed to her shell, and it was sending signals to Phillips' receiver. But she and Lovich thought the signals were bouncing around the canyon, misleading them. So they started back down the hill, toward the part of Cottonwood Canyon they'd taken to calling "Dead Sheep Canyon" because of the sheep bones scattered by a certain bush.
Before they got too far, Squirt was spotted, right where they'd been looking for her. Lovich grinned.
"You can see how this is some part science and some part art," he said. "We walked right around her in a circle."
Lovich and Phillips are part of a team from the United States Geological Survey that is tracking desert tortoises near the Coachella Valley. The slow-moving but wide-ranging creatures are listed as "threatened" under the federal Endangered Species Act, and researchers are trying to understand where they're thriving and how quickly they're reproducing — and how California's drought is impacting their odds of survival. On Tuesday morning, that meant traipsing around Cottonwood Canyon, finding the nine tortoises the team had outfitted with radio transmitters and taking X-rays of the females. The researchers have made the trip from Flagstaff, Arizona, every 10 days or so since April, when they first surveyed the area. They've found about 20 tortoises overall.
X-rays revealed no eggs Tuesday, but that was expected — breeding season lasts from April through July. Previous visits had yielded egg-filled scans, including one showing nine potential hatchlings in a tortoise known as Baby.
"If we have enough of them that don't produce eggs, it's possible the population is beginning to decline," Lovich, an ecologist, said.
Baby was active and unafraid on Tuesday, looking around alertly and trying to climb out of the box researchers used to carry her to their truck. Squirt was shy, keeping her head tucked away in her shell. A male tortoise known as Studmeister proudly stood outside his burrow and watched as the team approached, before gamely posing for photos.
Studmeister got his name because the first time the researchers saw him, he was intimately engaged with Baby.
"They have different personalities," said Laura Tennant, one of the researchers. "Sometimes they'll poke their heads out, be vivacious, have fun with you. Sometimes they'll be more reserved."
Another male tortoise is called Stub — short for stubborn, since he often refuses to emerge from his burrow. Josie is named for Josie Grossie, the unfortunate nickname for Drew Barrymore's character in "Never Been Kissed."
Then there's rock-loving Rockette, who was so hesitant to crawl out of her creosote-covered burrow Tuesday that Tennant had to lure her out by spraying water in front of her.
"She should have been named Stubborn No. 2," Tennant said.
The team has made some interesting findings, which could prove valuable to future tortoise protection efforts.
For one thing, the tortoises in Cottonwood Canyon seem to enjoy the rocky hillsides more than the flat desert floor, even though researchers had expected otherwise. The team has a few theories: Maybe predators have a harder time hunting them down in the hills, or maybe the tortoises prefer the shade. It's also possible that males are chasing females uphill, which Phillips described as the group's favorite theory.
The tortoises are certainly slow, but they're better at traversing steep slopes than many people. Lovich described them as having "a low center of gravity and a four-wheel drive."
"They're basically the ultimate climbing machine," he said.
Desert tortoises have also been impacted by the severe drought, Lovich said. His previous research has shown that tortoise survival is tightly coupled with three-year average rainfall — and the state is now suffering from a fourth year of historic dryness.
"If it doesn't rain next winter, my prediction is a lot of these tortoises will die," he said.
Across the Southwest, rising temperatures and epic drought are harming wildlife and plant life — and human-caused climate change is expected to make things worse. Already, higher temperatures are threatening Joshua Tree National Park's iconic, eponymous trees. The drought is also killing much of the vegetation that desert tortoises depend on, leading to die-offs.
The changing climate is only compounding the pressures on species like the desert tortoise, which have already been decimated by decades of expanding development and destruction of habitat.
"Although you think of the tortoises as a really tough desert species that can take anything, the prolonged drought takes its toll," said K.D. Fleming, who works for the Coachella Valley Conservation Commission.
The U.S. Geological Survey team is partnered with the commission, a sister agency of the Coachella Valley Association of Governments. As part of the Coachella Valley Multiple Species Habitat Conservation Plan, the commission works to protect desert tortoises, along with 26 other animal and plant species.
Fleming, the commission's habitat conservation management analyst, applied for $70,000 in state grants to fund the researchers' work. That money covers tortoise monitoring this spring and next spring.
Fleming plans to apply for more money, ideally to test for genetic differences between tortoises north and south of the Interstate 10. Her fear is that the freeway is too significant a barrier for tortoises to cross, which could cause distinct gene pools to form and lead to a decrease in genetic variability. It's a dangerous process known as inbreeding depression.
"We have a lot of questions, but not a lot of answers at this point," Fleming said.
