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Frogs, Toads Seek Ranches As Safe Haven From Development

By:
Chris Eversole

Source(s):
George Tanner (352) 846-0570

LAKE PLACID — Threatened with urban development as never before, frogs and toads increasingly are finding refuge on Florida ranch lands, a University of Florida study finds.

“Why are we so interested in frogs and toads? Because they’re a crucial link in the food chain for all kinds of other wildlife,” said George Tanner, a wildlife conservationist with UF’s Institute of Food and Agricultural Sciences. “They’re like canaries in a coal mine, giving us an early warning on the overall health of the environment for all wildlife.”

With more growth coming, some wildlife species are clearly in trouble, he said. “Frogs and toads are essential in a food chain that extends to alligators, birds, snakes and all the way up to bears, deer and panthers.”

Ranches preserve two habitats that some frog and toad species need to survive, according to UF research at the 10,000-acre MacArthur AgroEcology Research Center near Lake Placid.

The first crucial habitat is seasonal ponds — ponds that dry up for part of the year, eliminating fish and large insects that prey on tadpoles. The second essential habitat is wooded areas that shelter adult frogs and toads.

Urban development often fills in seasonal ponds or turns them into stormwater retention basins that fish take over, sending about half of Florida’s 30 frog and toad species fleeing. “We don’t know how they do it, but these species somehow know not to breed in fish ponds,” Tanner said.

While urban areas are unfriendly to some frogs and toads, ranchers keep enough seasonal ponds intact for them to use, the research shows.

“There had been a fear that draining ranches to improve pastures eliminated seasonal ponds, but we found many areas remain that hold water long enough for frog and toads to breed,” Tanner said.

Ranchers have their own reasons for this, he said: “Maidencane grass grows in the seasonal ponds, and it provides cattle forage when the ponds dry out.”

Ranchers also like to preserve wooded areas — crucial habitat for adult frogs and toads — a hop, skip and a jump away from seasonal ponds. “These areas provide shade for cattle, but they also are important habitat for frogs and toads as well as deer, wild turkeys and other animals,” Tanner said.

Researchers elsewhere have found that even when developers set aside “native” areas, frogs and toads that need seasonal ponds are eliminated.

“As urbanization increases, our biodiversity declines,” Tanner said. “If someone destroyed a work of art, we would decry the act, and we should be equally upset By the declines we’re seeing in frogs and toads.”

The research on frogs and toads provides new understanding of how ecosystems function. “Learning how frogs, fishes and insects in wetlands fit into the overall food chain is key to developing management practices that protect these critical links in the environment for wildlife,” Tanner said.

The gopher frog is a good example of the complexity of wildlife ecosystems, he said. It not only needs seasonal ponds but also can survive only where the gopher tortoise is present. State officials list both the gopher frog and the gopher tortoise as “species of special concern.”

Development doesn’t deter all frogs and toads. Some species breed successfully alongside fish.

Others, including the prevalent squirrel treefrog, need less than a month of standing water for their tadpoles to undergo metamorphosis. “When they hatch in the spring, there’s generally enough standing water for them to develop,” Tanner said.

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