It didn’t look good for the dusky gopher frog. By the early 2000s, scientists knew of fewer than 100 adults left at a single seasonal pond in southern Mississippi, and that population faced an imminent threat: The water kept drying up before the tadpoles turned into frogs, killing them. Then, to make things worse, a parasite hit. A few survivors were taken into captivity. They refused to mate.
But two decades later, the frog’s trajectory has turned around. While the species remains critically endangered and still relies on intensive interventions, its numbers have grown to around 600 adults, spread out over some 15 ponds and a handful of captive populations that now produce offspring.
It’s been a roller-coaster ride. Over the years, collaborators — from federal and state agencies, academia, zoos and other conservation organizations — have lived through crushing lows, dizzying highs and chronic worry over the three-inch frogs. There have been brushes with disaster, like when critical genetic diversity was saved by relocating two frogs at a crucial moment. There have been quixotic quests to kindle froggy romance: Entire ponds have been constructed at the Memphis Zoo to tempt captive populations into mating.
50 States, 50 Fixes is a series about local solutions to environmental problems. More to come this year.
Not to mention the mundane logistics. Some of the most important work has to happen on frog time (at night) and in frog weather (pouring rain).
“I tell my prospective employees to think of the worst time to have to be at the breeding pond all night — for example, your partner’s birthday — and expect the frogs to breed then,” said Joseph Pechmann, a population ecologist at Western Carolina University who has studied and helped conserve the species for more than 20 years. “Dusky gopher frogs often breed on Valentine’s Day!”
As humans propel a growing biodiversity crisis that is hitting amphibians especially hard, the humble dusky gopher frog is an example of what can happen when people work together in the opposite direction, helping a species regain numbers and restoring habitat that had been taken away.
“We can breathe a heavy sigh of relief,” said CJ Hillard, a biologist with the Mississippi Department of Wildlife, Fisheries and Parks. “One bad hurricane or one bad event isn’t going to cause an extinction.”
Dusky gopher frogs were once plentiful in Mississippi’s longleaf pine ecosystem, and their range extended into Louisiana and Alabama. Like many amphibians, they rely on ponds that fill up in the winter and dry in the summer. Eggs and tadpoles mature in these seasonal ponds, safe from the fish that would otherwise gobble them up.
Adults spend most of their lives away from the water, hunkering down in burrows made by gopher tortoises or other animals and only returning to the water to mate. When threatened, they cover their bulgy eyes with their front feet and secrete a bitter substance through their skin, a characteristic noted in a 2018 Supreme Court decision that went against the frogs.
Their small size and reclusive nature stand in contrast with the call they make: a loud, deep, repetitive rumble that is often compared to snoring.
“It sounds like your old, overweight uncle snoring in an easy chair,” said Steve Reichling, director of conservation and research at the Memphis Zoo.
Those striking calls faded over the course of the 20th century as the frog’s habitat was degraded and fragmented by logging, farming, residential and commercial development, roads and fire suppression (longleaf pine is a fire-dependent ecosystem, and research has shown that frogs struggle when their habitat doesn’t burn every few years).
By 2002, when the frogs were placed on the endangered species list, scientists knew of only one site where they still existed, a seasonal pool named Glen’s Pond. At that point, the frogs needed emergency measures: For the previous few years, all the tadpoles had died because the pond was drying up before they could metamorphose and survive outside water.
The reason behind the frequent early drying remains unclear. Climate change is probably a factor, Dr. Pechmann said, although research has not been conducted to prove or disprove a connection. Fire suppression, which lets trees encroach and suck up moisture, has also played a part, he said.
To try to save the species, Dr. Pechmann and his students brought in cattle tanks, normally used for watering livestock. They collected parts of egg clusters, hatched them in a lab and placed some of the tadpoles in the cattle tanks. Once they became froglets, they were released.
The next year, a new setback hit: a parasite.
“It was just a slaughterhouse,” recalled Dr. Reichling of the Memphis Zoo, who had made the six-hour drive to the pond after hearing about what had happened. “All these thousands of tadpoles were bloating and rotting in the pond.”
Here and there, he saw a few dozen tadpoles flopping around. He quickly got permission from the U.S. Fish and Wildlife Service, which manages terrestrial animals and plants listed under the Endangered Species Act, to collect about 60 and take them to the zoo.
“I thought maybe we could breed these in captivity and develop an insurance colony,” Dr. Reichling said. “Because at that time, it was pretty obvious that this species was probably going to go extinct in the wild.”
The problem was, they wouldn’t mate.
Rain prompts breeding for many frogs; in captivity, that rain often comes from a shower head. The dusky gopher frogs were unimpressed by that ruse. Next, zoo workers tried putting them outside, in open tanks, during thunderstorms. Nothing. They played a breeding call on a loop. Nope. They built an artificial pond. No dice. They lowered the temperature indoors during the winter, in case that had something to do with it. That didn’t work, either.
But dusky gopher frog lives are not long, and the clock was ticking.
In the mid-2000s, they switched approaches. Following protocols for other species, the Memphis Zoo began experimenting with in vitro fertilization, injecting frogs of both sexes with hormones. Sperm was collected from males’ urine. Eggs were massaged out of females.
It took some figuring out, but in 2008, for the first time in captivity, dusky gopher tadpoles wiggled out of their egg capsules.
Still, Dr. Reichling dreamed of getting the frogs to reproduce naturally, which would yield perhaps 2,000 eggs per female instead of 200. In 2018, a new pond was dug, complete with vegetation and burrows. Still, there was no action.
They kept making adjustments, to no avail. Some on the team thought it was a lost cause.
But then researchers in the field told Dr. Reichling that they were finding water depth to be very important.
Maybe the deeper water did it. Maybe it was something else. Either way, when they filled the pond more, the frogs started breeding the old-fashioned way.
During the last eight years, the Memphis Zoo and others have released over 7,000 froglets and over 6,000 tadpoles into two ponds in southern Mississippi.
“Frogs are now calling in the wild where they have not been seen in many, many years,” said Sinlan Poo, the zoo’s curator of research.
While the zoo was focused on captive breeding, another drama was unfolding in the wild.
In 2004, tiny populations were discovered at two other ponds in the region, but they were barely hanging on. By 2010, at one of them, two males were calling and calling without success. It seemed no females were left.
A graduate student of Dr. Pechmann’s collected two females at Glen’s Pond and drove them the 30 miles to the two lonely males. Soon, eggs appeared.
“We were able to save some of those genes,” Dr. Pechmann said. That student, John Tupy, now oversees dusky gopher frogs for the Fish and Wildlife Service. Another former employee of Dr. Pechmann’s, Mr. Hillard, is in charge of managing the frogs for the state.
Work continues to restore habitat. U.S. Forest Service employees at De Soto National Forest, home to Glen’s Pond, have used controlled burns, bulldozers and chain saws to open up the canopy and rehabilitate pools that were once withering away. Now it has 10 ponds where dusky gopher frogs breed. Other animals have also returned to the sites, including gopher tortoises (themselves imperiled), salamanders, snakes and other species of frogs.
Ed Moody, a wildlife biologist with the Forest Service who has worked on the restoration efforts for two decades, said communication, partnership and relationships were key. “If it wasn’t for those three things,” he said, “the frogs would have been extinct a long time ago.”
At Glen’s Pond and some others, eggs from the wild are still moved to cattle tanks to help them survive. But many of the restored ponds hold water long enough for tadpoles to turn into frogs and start living on land.
Federal grants have funded much of the work, along with money from the state, nonprofit groups and others. Recent federal cuts have biologists worried. The slog of long rainy nights continues. The end isn’t yet in sight.
But to those in the fight, the dusky gopher frog’s unique existence — its call, its look, the way it defends itself, the fact that it survives in burrows for months without desiccating — makes the efforts worthwhile.
“To me, that’s the definition of precious,” Dr. Reichling said. “It’s something that’s rare and irreplaceable.”
