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Phoenix Zoo Works To Save Endangered, Threatened Species

By one conservative estimate, humans have sped up vertebrate species loss to 100 times the normal rate, and some scientists say the planet’s sixth mass extinction has already begun. But a little-known facility at the Phoenix Zoo is working to save what it can.

Stuart Wells, director of the Arthur L. and Elaine V. Johnson Foundation Native Species Conservation Center, said his work is consistent, in a way.

“There are no typical days, except for every day is not typical," Wells said.

When your task is to restore 10 local species whose survival is endangered, threatened or just plain uncertain, there’s no instruction manual — only science and ingenuity. Wells also works with Arizona Game and Fish, U.S. Fish and Wildlife Service and other partners to improve outcomes for the state’s 50-plus endangered and threatened species

INTERACTIVE: Timeline Of Arizona's Threatened And Endangered Species

Case in point: A water-tank nursery where staff members work to build up Chiricahua leopard frog populations faster than habitat loss, invasive predator competition and disease can knock them down. Like many amphibians around the world, the frog has seen its population decimated by a fungal skin disease called chytridiomycosis, or chytrid.

“The challenge is trying to augment wild populations in a way that is getting ahead of the decline. Sometimes you actually need a place that can, that can protect those animals until they get to a size where they can be released," said Wells.

Safe in these tanks, 75 to 80 percent of these vulnerable eggs grow to survivable young adults, or metamorphs. That’s compared to 5 percent in the wild. But Wells said that reaching that success rate took some fine-tuning.

Temperature affects frog development, so the team used water heaters to bracket in the ideal range. It worked: In 20-plus years of captive breeding, they have released more than 23,000 frogs.

Ruth Allard of the Arizona Center for Nature Conservation, based at the zoo, said those successes result from the unique access the center provides. That access enables researchers to collect regular samples and study behavior up close.

“We can ask and answer questions — or get better answers, if we can — to questions that have been stymying folks in the wild for years."

That includes hidden and poorly understood behaviors, such as the crucial question of how solitary, territorial Mount Graham red squirrels mate. Following drought, insect infestations and stand-replacing fires that wrecked their sole habitat, only about 250 of them remain in the wild.

“You can’t just throw them together and hope for the best. They won’t tolerate that," said Allard.

Wells’s staff came up with an effective, if humble, way to gauge if the squirrels were more likely to mate or pick a fight.

“We can track what we call fecal steroid analysis and look at hormone variations over time by collecting poop and analyzing it," Wells said.

Finally, a nail-biting success: the first-ever captive mating of the species, although it produced no offspring.

“It’s still tricky. We haven’t cracked the nut, so to speak," Allard said.

Jan Schipper, the center’s field conservation research director, said that, beyond boosting species numbers, conservationists must also ensure animals retain the behaviors and instincts they need to survive.

“So the problem is, if you pull a population out of the wild, and if you leave them out of the wild for very long, they can begin to lose some of their trained behaviors, or learned behaviors."

Beyond these walls, the center works with partners like Arizona Game and Fish and the U.S. Fish and Wildlife Service to survey or restore habitat and release the animals. It also pursues global conservation through its Field Conservation and Science Grants Program and by coordinating with fellow members of the Association of Zoos and Aquariums. Since 2008, the grant program has funded $500,000 in projects. In 2015 AZA members spent $188 million on more than 3,200 conservation programs in over 100 countries.

“I mean, I think anybody who works in this field needs to be working in partnership. There’s almost nothing that any single organization can do by itself," Schipper said.

As Congress eases rules for selling public lands and considers measures to weaken the Endangered Species Act, conservation efforts may rely increasingly on such partnerships — and on private facilities like the Phoenix Zoo, which supports the conservation center with a portion of its gate receipts.

Nicholas Gerbis was a senior field correspondent for KJZZ’s Arizona Science Desk from 2016 to 2024.