CPW Focuses on Boreal Toad Survival
In mid-September Biologist Dan Cammack walked slowly along the edge of a boggy pond in the San Juan Mountains high above the San Luis Valley and peered into the mud and black water looking for a camouflaged critter the size of a dime.
After just a couple minutes, he saw the jumping movements of tiny boreal toads. The amphibians, colored a brownish-black, sat in the mud, on rocks, in the grass or moved on the top of the water attempting to stay clear of danger. Cammack had placed the toads in the ponds for the first time a few weeks earlier.
“Watch where you step,” Cammack said, “We don’t want to step on them.”
The toads are precious. Twenty years ago, they were abundant throughout Colorado’s high country. Today, however, they are scarce as they battle the mysterious chytrid fungus that is threatening amphibians throughout the world. CPW biologists are working statewide to revive populations of these high-altitude amphibians that live from 8,000 to 13,000 feet. But as is the nature of wildlife research, biologists will not know for at least three years if the work will help toads survive.
To start the process, Cammack and his crew collected eggs from two wetlands in the Triangle Pass area near Crested Butte. The fertilized eggs, collected in early summer, were then taken to CPW’s Native Aquatic Species Hatchery in Alamosa where they were hatched in captivity. By late summer, they grew into tadpoles and were ready for stocking in the San Juans.
Boreal Toad Habitat
In the high country above the San Luis Valley, the West Fork fire in 2013 burned through 100,000 acres of forest. Paul Jones, a now retired CPW biologist, had seen research that suggested burned areas might prevent development of the chytrid fungus. He also knew, based on historic records, that toads had once inhabited the area. So he worked with the Rio Grande National Forest, U.S. Fish and Wildlife Service, Rio Grande Headwaters Restoration Project and the San Luis Valley Water Conservation District to build small levies in a wetland area to enhance and enlarge optimal reproductive boreal toad habitat. The area mimics wetlands created by beaver ponds ‒ favorite breeding areas for toads.
In late August, Cammack and his crew released about 2,700 tadpoles for the first time into the ponds. He traveled back to the area in mid-September to check if the tadpoles had transitioned to toadlets. All along the edge of the five-acre pond, he saw toadlets moving, swimming and hiding.
“It looks like we have a lot of survival,” Cammack said. “The next critical test comes when we come back next spring to see if they survived the winter and hibernation.”
What is particularly challenging for the biologists is that young toads are less likely than adults to contract the fungus. So biologists have to wait to know if toads are affected.
“Making a determination about whether the site is positive for chytrid will not be established for about three years,” Cammack explained. “And reproductive maturity is not reached for five or six years, so it will take patience to see if the toads will breed in these ponds.”
Until then, Cammack and his crew will continue to collect eggs and release tadpoles into the ponds. The ongoing work is needed to maintain multiple “age classes” of the amphibians.
Cammack noted that he has found a few boreal toads at various locations in the mountains. However, outside of the Triangle Pass area, breeding in the wild has been unsuccessful.
“While each sighting is encouraging, the numbers are a mere shadow of the past when toads were once thriving in the region,” Cammack said. “We hope that careful management and novel approaches to encourage reproduction will keep boreal toads from disappearing.”
CPW biologists throughout the state are working on a variety of boreal toad conservation projects.
“We’re working on creative ideas to help bring these toads back. Building these ponds in this burn area is one idea. Hopefully, one of them will work; but it will take time,” Cammack said.
And he’s hopeful: “With wildlife we have to manage with optimism.”
Joe Lewandowski is the public information officer for CPW’s Southwest Region. He’s based in Durango.