In the novel, thirteen-year-old Ava Bigtree has lived her entire life at Swamplandia!, her family’s island home and gator-wrestling theme park in the Florida Everglades. But when illness fells Ava's mother, the park's indomitable headliner, the family is plunged into chaos; her father withdraws, her sister falls in love with a spooky character known as the Dredgeman, and her brilliant big brother, Kiwi, defects to a rival park called The World of Darkness.
Swamplandia! provides examples of the following tropes:
- Adaptation Expansion: "Ava Wrestles the Alligator."
- All First-Person Narrators Write Like Novelists
- Braids, Beads and Buckskins: The Bigtree "tribe" wear this kind of getup (borrowed from their own gift shop) in their advertising material; in reality the family is entirely white, though all but Osceola are sufficiently tan to be somewhat plausible.
- Break the Cutie: In short order, thirteen-year-old Ava loses her mother to cancer, watches her family drift apart, is left at home by herself after her brother and father leave and her big sister vanishes, is raped by a grown man who offers to help her find her sister, loses her beloved pet alligator and ultimately loses the family theme park, which she began the book determined to save.
- Death by Newbery Medal: Potentially the fate of the red Seth; Ava notes that even if she wasn't killed by the Bird Man her survival in the wild is unlikely given her bright coloration.
- Ditzy Genius: Kiwi upon his introduction to mainland culture.
- Fire and Brimstone Hell: The "World of Darkness" theme park has this as its shtick, referring to its customers as "lost souls" and offering overpriced treats such as Hellspawn Hoagies.
- From Bad to Worse:...Mom was dead, so I thought the worst had already happened to us. I didn't realize that one tragedy can beget another, and another—bright-eyed disasters flooding out of a death hole like bats out of a cave.
- Hope Spot: Ava encounters several, most notably the appearance of the Bird Man.
- Homeschooled Kids: Kiwi, Ava and Ossie were educated by their parents because of their isolation from the mainland.
- I Just Want to Be Loved: Ossie's loneliness, isolation and grief drive her to search for love in the spirit world.
- Innocent Inaccurate: Some of the more obviously Magical Realism elements of the story may be more or less influenced by Ava's naïveté.
- Karma Houdini: The Bird Man.
- Magical Guide: The Bird Man, or so Ava believes.
- Maybe Magic, Maybe Mundane: Played heavily with regard to two plotlines: Ossie's relationships with ghosts and the Bird Man's claim to know a route to the Underworld. Although the latter is revealed as a deception on the part of the Bird Man, the former is left open to interpretation, although we are told that Ossie has been put on medication.
- Missing Mom: Ava's mother dies during the opening of the novel.
- Multiple Narrative Modes: The book is initially carried by Ava's first-person narrative, but starting from the point where her brother Kiwi leaves home, her chapters alternate with a first-person limited account of his experiences on the mainland.
- The Ophelia: Osceola.
- Planet of Steves: All the Bigtrees' alligators are named Seth, and Ava frequently refers to their alligators as "Seths."
- Plot-Triggering Death: The story occurs in the wake of Hilola Bigtree's death by cancer, which throws her family out of balance and puts the family theme park in peril.
- Posthumous Character: Two for the price of one: Hilola Bigtree and Ossie's ghostly fiancé Louis Thanksgiving. The latter is complicated by the possibility that he may not exist.
- Purple Prose: Ava's narration is especially prone to this.
- Rescued from the Underworld: Ava attempts this for Ossie.
- The Scully: Unlike Ava, Kiwi refuses to consider the possibility that their sister Ossie may really be interacting with ghosts and is sure that she's deeply delusional.
- Speaks Fluent Animal: Subverted with regard to the Bird Man; Ava assumes that he can understand bird speech as a language, but he can only detect patterns.
- Southern Gothic: Though a somewhat unusual example in that it takes place in Florida and has apparent and deceptive elements of Magical Realism, it otherwise fits the conventions of the genre in its juxtaposition of a decaying family home with a sense of local history and tragedy which informs the action.
- Swamps Are Evil: Ava doesn't have to venture far outside her beloved Swamplandia! to find Hell itself, and not in the way she expected.
- Wrong Genre Savvy: Ava thinks this is Magical Realism. It's Southern Gothic.
