Toad trackers head to mountain ponds
Editor’s note: Reporter Bob Berwyn is participating in the boreal toad research project in Cucumber Gulch and will file occasional field dispatches as the search for toads unfolds this summer. A BOG IN SUMMIT COUNTY – To the few passers-by on the rec path, it must have been a strange sight; 10 of us, decked out in shiny new knee-high boots, blue surgical gloves and carrying white five-gallon buckets. Standing shin-deep and bent over at the waist in a murky pond near Dillon Reservoir, I plunged my arm up to the elbow into the cold water and made a grab for an elusive amphibian.”Whaddya lose?” asks one cyclist, stopping for a minute under the gray, sputtering skies.”We’re trying to catch chorus frogs,” I answer, studying the waterlogged strands of decaying grass for jelly-blob egg masses and listening for frog chirps.”You’ve got to think like a heron,” said Kevin Rogers, a biologist. “Get poised, and then move fast.”Rogers, a Colorado Division of Wildlife researcher, wants to capture at least 20 frogs from the area to test for a chytrid fungus that’s been tabbed as a key factor in global and local amphibian deaths.
Each specimen gets its stomach swabbed 25 times with a sterile cotton swab. The samples are sealed and sent off for DNA testing; the frogs are then released.The best time to capture the cold-blooded critters is at night, he said, when you can spot their eyes reflecting the glow of a flashlight just above the surface of the water. He said searchers can also go high-tech, using laser-pointers to triangulate on the gentle croaking, which sounds a little like a finger running along the teeth of a comb.Cause of the crashThe day’s search ended in a shutout win for the home squad, as chilly weather sent the frogs hustling for deep cover, burrowing into the muck and clumpy grass at the edge of the ponds. Still, Summit County’s newest toad-tracking team is not discouraged. It’s only spring practice – the real game begins next week, with methodical surveys for boreal toads in Cucumber Gulch near Breckenridge. The goal of the study is to discover if toads – and the chytrid fungus that kills them – are there.With superb habitat for boreal toads in dynamic beaver ponds, Cucumber Gulch is a potential reintroduction site once biologists learn more about the fungus and whether some types of toads have a genetically inherited resistance.Testing chorus frogs for the fungus in the ponds between Frisco and Dillon helps establish the overall presence of the pathogen in the area, Rogers explains, adding that it’s also a good training session for toad hunters, since the chorus frogs are much faster and trickier. By comparison, the boreal toads lumber through the muck and grass.
“You can walk right up to them,” Roger said.The Division of Wildlife has for several years been monitoring boreal toads locally and around the state. Consistent monitoring will show how fungus and toads change over time and distance. The Summit data could show where problems will arise next, potentially giving those areas time for preparation. Rogers’ pondside seminar also included a warning: He wanted to make sure the fungus isn’t transported by the researchers. Thus, they are wore surgical gloves and bleached their boots at the end of the session. It’s a worry because biologists have not quite figured out why an astounding number of amphibian species have crashed in the span of just a few decades.Sweeping southWhat we do know is that nearly 32 percent of all the world’s 5,743 amphibian species are considered threatened. By comparison, only about 12 percent of the world’s bird species and 23 percent of mammal species are threatened, according to a recently completed Global Amphibian Assessment.Why should we care if boreal toads live in Cucumber Gulch, or whether they are dying because of the chytrid fungus? Why are we going to spend hours and hours wading though murky bogs, spending thousands of dollars, to find out?
There are, of course, more-or-less obvious implications of endangered species laws and related land-use regulations. That includes day-to-day management of Cucumber Gulch to protect boreal toad habitat.But it’s not clear how crucial the amphibians are to the ecosystems of High Country ponds, Rogers said. They don’t appear to be a critical food source for any predators, nor are their numbers high enough to be a factor in controlling any other species, though ants seem to be the preferred food for boreal toads, he adds.Pin-pointing chytrid-free areas and establishing populations of fungus-resistant amphibians in Colorado could be a big part of the worldwide conservation strategy, Rogers said.The Division of Wildlife has taken the lead in some areas, establishing an aquatic breeding facility and experimenting with amphibian populations to determine whether genetic resistance is a survival factor. An experimental boreal toad re-introduction project on Grand Mesa near Grand Junction is one of the very few attempts at conserving the frogs in the wild, Rogers said. “It’s sad,” said Rogers. The fungus is advancing southward toward Central America at about 25 kilometers per year. “If there are 60 amphibian species in an area, you can expect that to be reduced down to 30 after chytrid comes through,” Rogers said.At risk, for example, are the spectacularly colored poison dart frogs in Costa Rica, as well as many other amphibians in countries where eco-tourism is a key part of the economy. Vail, Colorado
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