Drought Harms Rare Georgia Wildlife but Rebound Expected

BUTLER — The first day of February, John Jensen peered into the murk of a pond that was recently nothing but a mud flat. Last spring it dried up in Georgia’s record drought, stranding the tadpoles of rare gopher frogs.

"It was a puddle of really warm water with wading birds just picking them off," said Jensen, the state herpetologist. "The next week it was just cracked mud and carcasses."

Jensen recently searched the pond at the Fall Line Sand Hills Natural Area for frog eggs among golden grasses waving gently underwater. There were none yet. But he spotted a few leopard frog tadpoles, and ornate chorus frogs called from the bank with a sound like sonar blips.

Although the pond filled in the past month, it remains lower than usual. Jensen fears that even if gopher frogs have another good breeding season, without heavy rains the tadpoles will die in the sun again.

Gopher frogs aren’t the only ones suffering. The record Georgia drought has harmed some of Georgia’s most endangered and threatened species. The number of endangered wood stork nests dropped by almost half last year. Biologists believe endangered flatwoods salamanders have spent years unable to breed. And rare fish must dangerously rub fins with their predators in shrunken rivers.

State wildlife officials say many species have likely taken a hit, but most are expected to recover rapidly unless the drought continues several more years. Still, human changes to Georgia’s natural landscape may cause droughts to have a greater effect on animals than in the past.

AMPHIBIANS AND REPTILES

The state purchased the Fall Line Sand Hills Natural Area in 2006 mostly to protect the fishless ponds, which are an amphibian oasis. They host not only gopher frogs but also newts and salamanders that are among the only amphibians in the United States that can choose either lungs or gills as adults. On the banks grow Georgia’s largest stand of endangered pondberry.

But the habitat disappears along with the water.

As long as an adult breeding population remains, animals can survive a few years without breeding success.

Most frogs, and some turtles, migrate upland and burrow among leaf litter during dry weather, Jensen said. The barking tree frog hides in hollow trees.

"A one-season issue is just a blip and happens all the time," Jensen said. "Extended dry conditions lasting seven or eight years is a compounding problem." He also said conditions have mostly been dryer than normal since about 2000, during the last drought.

The growth of the human population makes the effect worse.

"There have probably been local extinctions," Jensen said. "In the past when we had a fairly continuous natural landscape, there would be adjacent populations that would eventually reoccupy these areas. But we just don’t have that connectivity now."

Jensen said this is likely happening with the endangered flatwoods salamander.

In all but one of the three known breeding areas where they occur in Georgia, the elusive animals haven’t been seen for seven years. The salamanders don’t appear until winter rains trigger a brief but large breeding migration to cypress ponds that dry up soon afterward.

Some species suffer when the drought cuts off their food supply.

Chicken turtles eat dragonfly larvae, which are found mostly in fishless ponds vulnerable to drought. And the threatened southern hognose snake eats toads that breed in similar short-lived wetlands, Jensen said.

ENDANGERED

WOOD STORKS

Last spring, even before the drought had worsened, endangered wood storks already were suffering. The tall, bald, long-legged wading birds rely on isolated wetlands for feeding and swamps for nesting.

An aerial survey in 2007 showed the number of stork nests had dropped by almost half, from 1,918 in 2006 to 1,054. The 2008 survey will likely be conducted in May, said Brad Winn, coastal program manager for the state Department of Natural Resources’ nongame section.

Storks, which nest in Georgia, Florida and the Carolinas, depend on standing water under their nesting trees. That’s because alligators below prevent raccoons from stealing the eggs, said Jim Ozier, nongame program manager for the state Department of Natural Resources.

"Often as soon as a site goes dry, raccoons totally raid it and there is zero nesting success," he said.

Many wood storks that did build nests last year failed to raise chicks. University of Georgia researcher Larry Bryan monitored 244 wood stork nests in Georgia and southern South Carolina last year and found that only half fledged young. That success rate has reached 80 to 90 percent before, according to a DNR news release.

The drought also affects the storks’ ability to find food. They wade through shallow water with their mouths open, snapping their beaks shut on small fish and animals that drift in. This method requires a concentrated food supply, which is usually found in isolated wetlands that are among the first to dry up in a drought, Ozier said. The state’s population of storks had made huge gains since 1980, when there were only 262 nesting pairs, Winn said.

But the last drought, which lasted from 1999 to 2002, also caused a dip in the growth of the population, according to the U.S. Fish and Wildlife Service. Storks tried some creative breeding sites in Georgia during that period, Winn said, adding that they probably could survive several years of drought before the number of adult birds started to drop.

Logging extends further into historical wetlands during drought periods, which can harm stork habitat, Ozier said.

But he and Winn agreed the worst habitat threat is the illegal draining of wetlands for development along the Georgia coast.

UNDER WATER

During a drought, fish lose some of the water that is both their home and their food supply.

DNR fish specialists say lower water levels cause fish to crowd closer together, potentially aiding the spread of disease and increasing competition for food.

Middle Georgia’s robust redhorse is a fish so rare it had disappeared for two centuries before recovering somewhat in recent years.

Jimmy Evans, DNR fisheries biologist, said the drought may force young fish into close quarters with their only predator, flathead catfish. But it’s unlikely to affect their ability to produce more fish, because they can spawn well in water just 6 inches deep.

"I would view the drought as an unfortunate event that would reduce rearing of young fish," Evans said. "We don’t regard it as catastrophic."

The drought’s timing is poor for Evans and others who have been striving to recover the species, which qualifies for endangered status.

The unusual fish cracks open mussels with its teeth.

Georgia’s only wild population of the fish is in the Oconee River. But the state, with the help of universities and power companies, has stocked them in the Ocmulgee and two other rivers.

This is the year Evans had hoped to learn if the eggs of the stocked fish were hatching and the young growing into the adult population. This would indicate the stocking program has been successful.

The animals that have made the biggest news during the drought are probably freshwater mussels. With Atlanta forced to limit the amount of water it takes from river systems that are home to rare mussels, Gov. Sonny Perdue and some other politicians have portrayed the "water war" among Georgia, Alabama and Florida as "man versus mussels."

"It’s really man versus man," said aquatic zoologist Jason Wisniewski, pointing out that fishermen and others earn their living from the shellfish and oysters that are harmed by dropping river levels.

"For some reason, mussels get a bad name," he said. "They’re not charismatic, but they do filter a whole lot of water, which we pay millions of dollars to do for drinking."

Wisniewski said surveys during the past two years showed a drop in the population of rare mussels in the Ocmulgee, Oconee and Altamaha rivers, probably because of the drought. Some of these species, such as the Altamaha spiny mussel, are found nowhere else on earth.

Freshwater mussel larvae feed harmlessly on the gills and fins of certain fish species, but scientists still don’t know which fish. Although the mussels can inch down as the water level drops, no one knows whether the drought is harming their host fish.

Wisniewski noted that mussels have survived centuries of droughts in Georgia.

It’s when natural conditions are altered by developments or reservoirs that droughts become more dangerous to animals, he said.