As we walked the mown trail, the landscape to either side a patchwork of thick wiregrass and glassy, rippling water, he held binoculars to his eyes, searching for a spot he wanted to show me, where a pair of great horned owls recently kicked a bald eagle out of its nest. (Sure enough, when we found it, the viewfinder revealed two distinctly owl-shaped heads poking out of the top of a great shallow bowl.) All around us were organisms that wouldn’t look out of place in a Jeff VanderMeer fiction: a spiny, two-foot wide thistle, marbled green and purple in a hallucinogenic pattern; rough-backed alligators still as waterlogged wood; thin-necked, elongated birds; shaggy, top-heavy trees that appeared to sprout straight up from the water, rooted in current. “I find parts of this landscape look very primordial,” he said as he looked out over the water, “and even when they’re not still, they give off a kind of stillness.”

VanderMeer attended to his surroundings with unusual care — crouching to capture a photo of a white, orchidlike flower, pausing when he spotted a bird or mammal on the path ahead of us so it could clear out calmly, without fleeing. “Annihilation” was inspired by this landscape, but the novel he is currently writing is actually set here: an eco-thriller about animal trafficking inspired by the pine forests and salt marshes of the Panhandle, with a major emphasis on salamanders. In conversation, we circled back again and again to the ways human activity impacts animal life. He told me about a trail near the St. Marks Visitor Center that had to be closed because the foot traffic was startling the ducks, who took flight so often that they burned through their winter fat. A few years ago, VanderMeer traveled to upstate New York to help band saw-whet owls, but the conservation effort took a dark turn: some of the tagged owls were released near larger owls, which ate them immediately. “I’m fascinated by these scientific studies, because the scientists themselves change the animals’ behavior,” he told me. “Musk oxen, for example. They found that when they tranquilize and band them, they go into a deep depression. They don’t go back to the herd for the longest time.” With a glint of mirth, he added, “I mean, if you think of it, it’s almost like getting abducted by aliens.”

VanderMeer has founded his writing career on exploring the wilderness of the strange, the stranger forms of strangeness that live on the brambly margins of conventionalized narrative. It’s a strangeness that bears a certain kinship to the wild Florida spaces near where he grew up and the moody, shifting terrain we’ve been navigating this afternoon — eerily still and eerily alive at once.

Born in Pennsylvania to parents who enlisted in the Peace Corps when he was 3, VanderMeer spent his early years with his parents and younger sister in Fiji. The VanderMeers lived by the sea in Suva, the capital, while his father taught chemistry at the University of the South Pacific and his mother worked as a freelance biological illustrator. Near the city was a volcanic peak that offered a reliably cool breeze and a view of the city and sea below; otherwise, the climate was warm and humid, and he spent time by the water staring at the tidal pools, filled with an ever-changing selection of life — moray eels and anemones and brightly-colored starfish. They eventually settled in Gainesville, Fla., where his father worked as a U.S.D.A. scientist and went on to win awards for his research on the hormonal systems of fire ants. An overgrown man-made pond sat in the backyard of their rented house, and VanderMeer watched from nearby as turtles colonized the murky water, seemingly materializing out of nowhere.

In his junior year of college, VanderMeer dropped out to spend more time writing fiction. The creative-writing department at the University of Florida was closed off to more fantastical avenues of writing, and he was already working on building a community of his own, based around a reading series he had started with a friend. When writers came to town for the university’s reading series, VanderMeer would approach them and ask if they’d be interested in doing another reading afterward not far from campus. It was through this reading series that he met Ann Kennedy, now Ann VanderMeer, who edited the avant-garde fantasy publication “The Silver Web” and worked as a software manager — a trailblazer in two male-dominated industries.

VanderMeer began to publish regularly with genre magazines and presses where his work was something of an outlier: surreal, Borgesian screeds and offbeat fantasy tales that confounded some fantasy readers because, even though they were set in otherworldly, imaginary places, nothing particularly fantastical ever happened there. Like a mad scientist, he mixed and recombined genres, concocting peculiar hybrids like “Finch” (2009), a “fungal noir” about a detective assigned to solve the murder of a “grey cap,” one of a race of mushroom-like spore-based entities that seized control of the city after a long and destructive period of human infighting. His works often overgrew their intended boundaries, with first editions issued in paperback, followed a year later by a hardcover edition twice as long and crammed with additional material — and sometimes artifacts like votive candles and dried mushrooms, the fictive story lines spilling out of the page and into three-dimensional reality.

Though this earlier work was always obsessed by nonhuman life and the complicated links between people and place, the 2010 Deepwater Horizon oil spill in the nearby Gulf of Mexico provided an urgent ecological frame of reference for VanderMeer’s work. In “The Southern Reach” and his follow-up novel, “Borne” (2017), he focused on depicting large-scale, catastrophic environmental change through unsettling, bizarrely touching transpositions. Beneath the enigmatic surface of Area X is a deeply familiar dynamic, with loss of habitat and loss of world driving a certain melancholy acceptance in those who visit the area. Its exact nature is never fully explained, nor is it clear that the contamination of our world by a new one means an end to human life — but the wildlife that thrives in the area exudes an un-animal-like presence, and the people who occasionally return from exploratory missions are different, emptier, with a distant stranger’s understanding of the facts of their own life. Area X is to human beings what human civilization has often been to other species: a spreading, transformative force that renders a once-familiar world hostile and unpredictable.