A large portion of Boyd Hill Nature Preserve's gopher tortoise population has died.
Officials said nearly 60 carcasses have been found in the South St. Petersburg preserve over the last month and a half.
Elise Bennett is the Florida and Caribbean director for the Center for Biological Diversity. She said despite the small population at the preserve, it's a stronghold for the species.
"This number of dead tortoises that they've found is a concern for the population as a whole, when you think about the percentage of the population that's been lost," Bennett said.
There are also environmental concerns when a tortoise population sustains major losses like those seen at Boyd Hill, because it takes them a long time to recover.
The tortoises can live up to 80 years, but reach reproductive maturity very late.
"There really aren't any other places like Boyd Hill where there's a large enough population that receives the conservation attention it needs to continue surviving," Bennett said.
Investigating the deaths
Eckerd College associate professor of biology Jeff Goessling studies the tortoises at Boyd Hill through a research method called "mark, release, recapture." They individually notch tortoise shells and can identify them through many parameters like sex, age, and size.
He said quite a few of the species they studied have died during this large-scale mortality event.
"The biggest adult female that we had in the population is one of them that's died," Goessling said. "We had a radio tracker on her, we know how many eggs she's produced over the past couple of years. We know where she lived, we know her size."
Goessling said while the event is not the norm and could be perceived as "alarming" — but as long as the city continues to maintain the habitat, he believes the tortoise population will be able to rebound.
The deaths are still being investigated by the Florida Fish and Wildlife Conservation Commission (FWC). But Goessling suspects coyotes to be responsible for the tortoise deaths.
"We're not finding them dead around gopher tortoise burrows out in the open, high-quality habitat," he said. "Instead, we're finding what were very recently healthy animals, kind of cached and eaten and dead in hollowed-out shells."
Last year, Goessling noticed that many of the tortoise burrows his team tracked were dug up by coyotes.
"But the tortoises are deep enough underground, that they can kind of evade the coyotes. That's why they burrow in the first place is to get away from predators," he said.
So he believes over the past few years, the coyotes have changed their strategy and began snatching tortoises walking around in the middle of the day.
"There's no reason to believe that a third of our tortoises have just haphazardly died," he said. "But we have found a third of them dead, surrounded by coyote scat where coyotes have been chewing on their shells."
The FWC tried to collect samples, but were unable to find any fresh carcasses, instead only healthy live animals.
They will test the shells they did find for several pathogens that affect tortoise populations.
Meanwhile, officials are setting up four trail cameras on the property — two on active burrows and two scanning the nearby area — to monitor coyote interaction with gopher tortoises.
Data will be reviewed at the end of the month.
The legal fight to protect tortoises continues as well
Gopher tortoises are one of five tortoise species found in the southeast U.S. They tend to live in dryer, higher elevations with sandy soils, but can be found in coastal dunes and other kinds of uplands as well.
Bennett calls the tortoises "stewards" of the southeast's uplands.
"The tortoise and its burrow is incredibly important for the survival and well-being of hundreds of other species and the landscape they share," she said.
The gopher tortoises are unique because they are federally listed as threatened under the Endangered Species Act for the portion of the species west of the Mobile and Tombigbee Rivers in Alabama.
But the portion that live east of the rivers do not fall under these federal protections. The Center for Biological Diversity has been trying for more than a decade to change that.
The Center filed suit last year against the U.S. Fish and Wildlife Service, challenging the decision to deny protections for the eastern population.
"This specific situation, and more broadly what's happening with gopher tortoises, only underscores that we need to act now and get stronger protections for them and for their habitat," Bennett said.
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