[Array of islands in the Florida Everglades overlaid with contemporary networks of dykes and roadways. Landsat courtesy of NASA]
According to paleoecologist Gail Chmura, the paramecium-shaped islands rising from the flat expanse of the Everglades are “just one of a number of cases where people and human disturbances played a major role in landscape development.”
Scientists have generally thought that humans didn’t affect the Everglades in any significant way until recent times. But long before corporate sugar plantations arrived, or orange groves, canals, levies and other terraforms, we dwelled on the islands, which in turn further constructed them:
“As scientists chisel through hard layers of rock and dig up piles of ancient and buried waste materials, they are finding evidence of settlement, abandonment and resettlement in the area, beginning more than 5,000 years ago…By piling up mounds of fish remains, turtle bones and other waste products, these people probably altered the chemistry of the soil and raised the elevation of the islands, making the land even more welcoming to all kinds of life…As the waste dissolved and broke down, discarded bones in particular would have helped create productive, phosphorous-rich soil.”
Given the scale and sheer number of the islands, it’s not likely humans made all of them. Rather we probably took refuge on existing geohumps, enriching them with our waste products in the process. The irregular distribution of the islands still provides unanswered questions as to their formation and the fascinating interweaving of anthropogenic and other forces. Miniscule plateaus in the surface of the limestone base – just an inch or so above its surroundings – could begin to collect peat and other matter, initiating a self-aggregating process. Given the Everglades flatness, elevating the islands by a foot or more engenders a whole new range of thresholds, habitats and vegetation; thus their name – tree islands. It fascinating to speculate about whether these compost piles were deliberate design or inadvertent effect, or inadvertent effect that became cultured, deliberate design. Equally interesting to think that our inhabiting of the Everglades once helped amass soil and its living medium in direct contrast to its wholesale erasure.