Fire on the Prairie: Florida’s Archbold Biological Station
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Time to read 12 min
Florida Grasshopper Sparrow. Photo by Alex Marine.
While studying grasslands as a masters student in Kansas, Mary Marine asked a colleague about the grasslands in her native Florida, a dry prairie that once covered half a million acres of the state’s interior. “And they told me, ‘Florida doesn’t have prairies. Florida doesn’t have grasslands.’”
“But we do, and they’re so unique,” says Marine, a researcher with Archbold Biological Station who works in that ecosystem. “It’s like no other habitat anywhere.”
Indeed, the Florida dry prairie is a far cry from Kansas’s tallgrass prairie. It isn’t the kind of place that comes to mind when one thinks of Florida. Though dry most of the year, seasonal flooding means that part of it is underwater for a couple months. “I haven’t heard of that in any other grassland system,” Marine says. With a complex mix of herbaceous plants and shrubs, prairie hammocks and wetlands, it’s one of the most biologically rich grasslands in the world, according to ecologist Reed Noss.
But what shapes this whole landscape—what all the plants and animals depend on—is fire.
Archbold researcher Mary Marine finds a Florida Grasshopper Sparrow nest in healthy dry prairie habitat. Photo by Keigan Case.
Florida’s one of the lightning capitals of the world. If you imagine the state before human settlement, a wildfire would sweep across the prairie and other habitats surrounding it, such as oak scrub and flatwoods, for as long as there was fuel to burn. It was stopped only by rivers, lakes, or those seasonal rains.
Today, lightning still strikes, of course, but the spread of fire is slowed by human efforts and artifacts: cities, suburbs, roads, highways, cattle ranches, and agriculture. Ninety percent of the Florida dry prairie has been lost, mostly to pasture but some to development. The oak scrub habitat is another ecosystem where Archbold’s biologists work, a sandy place with gnarled little oaks and, in the high and dry spots, Florida rosemary bushes (a plant not related to the herb). Historically, Florida’s scrub ridges have been targeted as prime land for citrus groves, and today, housing.
Florida scrub ecosystem at Lake Wales Ridge State Forest.
Which is where Archbold Biological Station comes in. In 1941, Richard Archbold, an explorer, environmentalist, and patron of scientific research, founded the station on over a thousand acres of scrub land eight miles south of Lake Placid, Florida. The property had been owned by John A. Roebling II (the grandson of the Brooklyn Bridge’s designer and the son of its builder) and Margaret Shippen Roebling. Their son, Donald Roebling, donated it to his childhood friend Archbold when he couldn’t find a buyer. Archbold employed a team of scientists and regularly hosted over 40 researchers a year from around the world. Upon his death in 1976, he left the land, its buildings, and his personal fortune to the station.
Since that time, the station has grown to encompass approximately 20,000 acres. About half is a working cattle ranch and the rest is a mixture of grazing pasture and native habitats, including over 5,000 acres of the Lake Wales Ridge, a line of ancient sand dunes that sits to the west of the dry prairie. Formed millions of years ago from rising and falling sea levels, the Lake Wales Ridge acts as Florida’s backbone, and it holds the headwaters of the Everglades: a 2.6-million-acre watershed that delivers water to one of every three Floridians and flows to the famous swamps in south Florida.
Three Florida Scrub-Jays, part of a family group. Photo courtesy of Archbold.
Archbold’s many scientists have worked to study and conserve these rare ecosystems—scrub, dry prairie, and flatwoods—and the impact of fire on their plants, soil, water, and wildlife. This means conserving three bird species that are dependent on a fire-shaped landscape: Florida Scrub-Jay, Florida Grasshopper Sparrow, and Red-cockaded Woodpecker. Archbold’s staff call them the “big three.” They are all protected under the federal Endangered Species Act; the Florida Scrub-Jay and Red-cockaded Woodpecker are listed as threatened species, and the Florida Grasshopper Sparrow, a subspecies, as endangered.
The Florida Scrub-Jay is the symbol of Archbold’s commitment to long-term scientific study. In 1969, a Cornell alum named Glen Woolfenden working at Archbold put colored plastic leg bands on a few of the jays. Though the birds hadn’t been studied much, they were known to be nonmigratory and live in cooperative family groups, where the young from the previous year’s breeding season stick around to help their parents at the nest. Woolfenden knew he would be able to study the same individuals over time, so he used different leg band color combinations to track the members of seven different families.
Archbold researchers band every Florida Scrub-Jay so they can track individuals and family groups over their entire lives. Photo courtesy of Archbold.
Archbold researcher Tori Bakley, who supervises the Florida Scrub-Jay work, in the field. Photo courtesy of Archbold.
That population study continues today. Scores of interns and graduate students have learned the ins and outs of field ecology through following Archbold’s jays, by doing monthly censuses of the station’s entire population, finding and monitoring their nests, banding and blood-sampling the hatchlings, mapping each family’s territory, and even counting thousands of acorns. “The project literally watches them their whole life,” says Tori Bakley, a researcher who supervises this fieldwork.
The jays are monogamous, and with color bands and DNA tests, Archbold’s scientists have been able to create a family tree going back to the program’s beginnings—16 generations and counting, incorporating more than 9,000 individual jays. Such individual focus has allowed for the study of how the birds respond over time to changes in climate, food resources, and habitat. Florida Scrub-Jays can live for up to 15 years, and some of the territories at Archbold, they’ve found, have existed for decades, passed down through the generations. The offspring stay with their parents for at least two or three years—scientists call them helpers—and help to feed their younger siblings and to guard their territory.
Florida Scrub-Jays with their nest in a stunted oak. Photo courtesy of Archbold.
In 1977, Archbold began setting fire to a small plot of that habitat, restoring what was once a natural cycle. What they learned was instructive: a few families would occupy it in the first few years after the burn, growing to six or seven within a decade. After 15 to 20 years, the site would drop back to one or zero families. Additional burns confirmed that the number of scrub-jay families reaches its max about a decade after a fire. Bakley says this timeline is what they recommend to Archbold’s partners planning burns elsewhere in Florida’s scrub.
This fire management has shown immediate results: Since 2021, when Bakley joined Archbold, she has watched the number of family groups on the station grow from 75 to around a hundred, or about 400 individuals.
“You could have a lot of scrub preserved, but if it’s not burned regularly, then it can’t support many scrub-jays, if any at all,” she says. “We’ve lost over 90 percent of the scrub that once existed in Florida. Making the most of what we have left is the best thing we can do to help these jays. And our data has shown that they’re healthier and produce more fledglings when they’re in suitable scrub, as opposed to overgrown scrub or scrub within suburbs.”
And why is fire important to their overall success? The most optimal scrub is under two meters tall, Bakley says, since the jays nest about one to one and a half meters above the ground in stunted oaks that thrive in the dry, sandy soil. A natural fire cycle creates a lot of openings between the trees; the jays cache, or hide, acorns in the sandy patches. A more open habitat allows them to see predators like snakes, bobcats, and hawks.
Florida Grasshopper Sparrow. Photo by Alex Marine.
Like the loss of scrub, the disappearance of the historic dry prairie has narrowed the breeding range of the tiny Florida Grasshopper Sparrow, one of North America’s most imperiled birds. Unlike other eastern Grasshopper Sparrows, it is nonmigratory, and its physical appearance is slightly different—it is darker and has a larger bill. In the 1990s, federal and state wildlife agencies began surveying its numbers, and the picture was bleak. They brought in partners, including Archbold, to create the Florida Grasshopper Sparrow Working Group, in part to create a program that would breed birds in captivity and release them into the wild. In 2018, the wild population of Florida Grasshopper Sparrows dropped below a hundred; the next year, the first releases occurred.
Florida Grasshopper Sparrow on recently-burned prairie. Photo by Jesse Beck.
Mary Marine began working with the sparrows in 2020 at Three Lakes Wildlife Management Area, one of four preserves where they are regularly monitored. That year, biologists found released birds successfully pairing and breeding with wild Florida Grasshopper Sparrows. “It was the first time we had significantly more breeding birds than we’d had the year before,” Marine says. “It was a huge turning point for the project.”
Like Archbold’s Florida Scrub-Jays, every known Florida Grasshopper Sparrow is also fitted with color bands on their legs, Marine says, a project that has been ongoing for two decades. Marine and her team search for their nests not only to band the nestlings but also to protect them from predators and flooding and other hazards.
Marie Marine banding a Florida Grasshopper Sparrow nestling. Photo by Mary Marine.
Florida Grasshopper Sparrow nest on the ground, hidden in grasses. Photo by Mary Marine.
Marine values the intimate understanding of the species that comes with this intensive conservation. “When we’re talking about one of the most imperiled birds in the world, it’s incredible to be able to say, ‘I know these individuals. I know their personalities.’ You get to see one bird’s contribution to the continuation of its species. It makes the wins personal.”
The wins are hard-earned: during the last breeding season, the estimate of Florida Grasshopper Sparrows was around 200 individuals, more than double the low of 2018. “At the end of the day, they’re doing the work,” Marine says of the birds. “We can’t do it for them. We’re just supporting them as much as we can.”
Pair of Florida Grasshopper Sparrows carrying food. Photo by Mary Marine.
None of this work is done alone. One place where that’s clear is the Avon Park Air Force Range, a bombing and gunnery training range that stretches across 165 square miles of central Florida, where a long-running partnership of the U.S. Fish and Wildlife Service (USFWS), U.S. Air Force, and Archbold has helped bring the Red-cockaded Woodpecker back from the brink.
This small black-and-white woodpecker, found only in the Southeast, is another habitat specialist. It needs mature longleaf pine forests, and most have been lost to timber, agriculture, and development, leaving less than three percent of the bird’s historical range. The species was federally listed as endangered in 1970, with fewer than 10,000 individuals remaining.
Red-cockaded Woodpecker in a longleaf pine tree. Photo by Jeff Gardner.
All federal lands must comply with the Endangered Species Act, so in the early 1990s, the Air Force reached out to Archbold to survey its population of Red-cockaded Woodpeckers. Red-cockaded Woodpeckers also live in family groups, with male and female offspring (more commonly the males) staying to help their parents. Only 21 families remained, less than half of those found the previous decade. Biologists from the Air Force, USFWS, and Archbold developed a management plan that included three components: reintroducing frequent prescribed burns, building artificial nest cavities, and translocating Red-cockaded Woodpeckers from other forests to build up Avon Park’s population.
Avon Park has its own wildland fire crew that annually burns a quarter to a third of the property, or 25,000 to 30,000 acres, according to Archbold’s Greg Thompson, a researcher who has worked there since 2013. Woodpeckers like space between the pines and an understory mostly free of tall shrubs and mid-story trees. For the Air Force, regularly burning these flatwoods is not only useful for the birds. It’s a safety measure, too, since it decreases the risk of large fires that could be ignited by the military exercises that take place on the range.
Prime Red-cockaded Woodpecker habitat at the Avon Park Air Force Range, with mature longleaf pines and an understory mostly free of tall shrubs. Photo by Greg Thompson.
Unlike most woodpecker species, the Red-cockaded excavates its cavities in living trees. That process usually takes several years to complete, since live wood is harder to chisel than dead and decaying wood. Biologists have given them a hand by creating cavities for them. Some they drill directly into suitable trees; others they fabricate by installing rectangular wooden boxes. This intervention is not for those with a fear of heights. It requires standing on top of a tall ladder, using a chainsaw to cut a space for the box, and carefully wedging it flush against the trunk. When done properly, the birds hardly know the difference.
Artificial cavities create new territories for the woodpeckers in places where they aren’t presently but are expected to have success. But the birds still must find them. And so USFWS also helps in the translocation process, transplanting woodpeckers from areas with robust populations to places like Avon Park which can support more.
Archbold researcher Greg Thompson installing a cavity box for Red-cockaded Woodpeckers in a longleaf pine tree. Photo by Jen Guyton.
Roughly 70 percent of translocated birds at Avon Park have remained at the range. A recovery goal of 40 family groups was reached in 2020, and the current population of 46 groups is up from 21 when this work started. It’s not surprising: Avon Park’s pine flatwoods, regularly burned, are exceptional habitat, says Greg Thompson. So much so that another endangered species, the Florida bonneted bat—the rarest bat in the United States—makes its home in old woodpecker cavities.
All the “big three” birds are doing well at the range, Thompson says. “I think we have some small pockets of truly virgin longleaf, which is exceedingly rare in the Southeast. We’ve got some really nice scrub habitat. And we’ve got some of the last remaining good quality Florida dry prairie.”
Over time, Archbold has been able to help save large tracts of these native Florida ecosystems. Its mission now is connecting them to each other. Within the state, there is growing support for the Florida Wildlife Corridor, a long-discussed vision to protect 18 million acres of an ecological greenway from the Everglades up to the edge of Georgia and Alabama. For decades, Archbold has supported it with science and conservation efforts. In 2021, state legislators unanimously passed the Florida Wildlife Corridor Act, which makes the corridor a conservation priority for land acquisition, especially in the headwaters of the Everglades.
Swallow-tailed kites roosting before migration at Lake Woodruff National Wildlife Refuge, a vital part of the Florida Wildlife Corridor.
Connectivity is what will allow Florida Grasshopper Sparrows to move between prairies; Florida Scrub-Jays to move between fire-managed scrub; Red-cockaded Woodpeckers between longleaf pine forests; and even the Florida panther and Florida black bear to move across the state.
For Mary Marine, it allows her to see her work with the Florida Grasshopper Sparrows as part of a wild Florida in which all species have a place. “I’m out here with this small population and I’m working on a very individual level, but when you zoom out, it’s part of this huge picture. It lets the work matter not only today, not only for this one bird, not even only for this species, but for Florida and for all wildlife.”
Roseate Spoonbills and Wood Storks landing at St. Marks National Wildlife Refuge, an important part of the Florida Wildlife Corridor.
