April 13, 2019 - 12:15 am
Dozens of rare relict leopard frogs have been set free in their new habitat at the Springs Preserve.
Now it’s up to Raymond Saumure to keep them all from croaking.
Saumure is the environmental biologist for the Southern Nevada Water Authority who oversaw the design and construction of the preserve’s frog and fish ponds.
On Thursday evening, he helped release 86 froglets into the two interconnected concrete ponds at the northeast corner of the 180-acre, desert-themed attraction near U.S. Highway 95 and Valley View Boulevard in Las Vegas.
They joined roughly 100 relict tadpoles set free in the ponds about two weeks ago.
Saumure said the goal is to get the frogs to “take hold and breed on their own” at the Las Vegas Valley Water District-owned preserve.
The relict leopard frog was thought to be extinct along the Virgin and Colorado rivers before it was discovered anew near Lake Mead in 1991.
It was a candidate for federal protection under the Endangered Species Act until state and local agencies formed a conservation team to save the frog and keep it from being listed.
Saumure said the specimens released Thursday were supplied by UNLV researchers as part of that conservation effort. They were hatched from eggs collected from the wild, raised at a hatchery near Lake Mead and delivered to the preserve in buckets.
“They just transformed from tadpoles, so they’re pretty small,” Saumure said.
Survival of the ‘frog biscuits’
The inch-long brown frogs with spots on their backs should quadruple in size over the next four months — unless they die or get eaten.
“It’s an open habitat, and they’re part of the food web,” Saumure said. “They are just little frog biscuits for everything out there.”
In the wild, he said, only about 4 percent of relict leopard froglets typically survive to adulthood. The preserve saw roughly the same survival rate when the first 100 frogs were released into the ponds in May.
Saumure and company only found four adult frogs in the habitat last fall, and only two remained — one male and one female — when they were counted again this year.
“We’re hoping we can improve on that,” he said.
Fortunately for the frog, it only takes a few survivors to keep the population going. A single mated pair can produce 600 tadpoles, Saumure said.
The ponds at the preserve also were stocked with endangered Pahrump poolfish for the first time last year. Saumure said the 2-inch spring fish began reproducing within a few weeks and now numbers at around 400.
Rewilding a Las Vegas oasis
The Springs Preserve was built on the site of the spring-fed oasis that attracted the the first settlers to the Las Vegas Valley. The creeks and pools there used to harbor their own distinct types of frogs and fish, but those species were wiped out when the original springs were pumped dry as Las Vegas grew in the early 1960s.
By introducing two similar species, Saumure said, the water district is helping to “rewild” the site while delivering an important educational message about the fragility of desert ecosystems.
The current plan calls for additional batches of froglets to be released into the ponds each spring as part of a five-year test to see if the artificial habitat can sustain a breeding population.
The ponds were built beneath a 100-year-old stand of cottonwood trees along the historic Las Vegas Creek channel, just over the wall from the giant fox and Gila monster sculptures that greet motorists as they drive pass the preserve on U.S. 95.
Visitors can reach the habitat by walking trail, rented bicycle or the preserve’s replica train.
Just don’t be surprised if you can’t find any frogs when you get there, Saumure said.
The amphibians are well camouflaged and generally active only at night.
The females don’t make any sounds, while the males produce a subtle call Saumure likened to “a low chuckle.”
“If you go to the ponds in the daytime, it’s really rare that you’ll see a frog,” Saumure said.