Climate Change at Timucuan Preserve: Mangroves, Sea Level and Heat

The Fort Caroline model on the St. Johns River floods in storms and with rising seas. NPS.

National parks have a front-row seat to how climate change affects natural and cultural resources — and hundreds of parks tell of Americans innovating and organizing when the nation needed it. At Timucuan Ecological and Historic Preserve, climate challenges are met with partners, science and Indigenous conservation techniques.

Climate action: partners, staff and the public help in many ways — from collecting dragonfly larvae to monitor habitat to gathering oyster shells for the Living Shoreline program.

Plants: mangroves move north

Park staff found a large group of mangroves in the preserve — including what was then the northernmost mangrove ever found in North America. It is evidence that plant communities are shifting with the climate.

• What mangroves are: woody, tropical coastal wetland plants that tolerate tidal flooding and salt. In the U.S. they grow on the coasts of Texas, Louisiana and southern Florida, where they protect shores from storms and shelter fish.
• Three native species: black, red and white. The Timucuan group, in a salt marsh on Fort George Island, is mostly red mangroves — less freeze-tolerant than black.
• Why they're spreading: temperate zones are warming and extreme winter cold has become rarer. Mangroves spread propagules (seed-like structures) on water and tides, and storms carry them farther — in 2017, Hurricane Irma left huge numbers on Florida beaches beyond the usual range.
• The worry: they may displace native, more cold-tolerant salt marsh plants — and one hard freeze could kill them. "Long-term, I fear that large areas of salt marsh will be lost due to mangrove migration, and if we have a sustained freeze that destroys the mangroves, what will we be left with?" asks Steve Kidd, Chief of Resource Stewardship.

Rangers monitor biodiversity to track such shifts. More: Marching Mangroves.

Marking mangrove locations in the preserve's salt marshes. NPS.

Animals

• Sea level rise, from melting ice and a warming ocean, may flood salt marshes and coastal wetlands, taking habitat from migratory birds, fish and crabs. The roseate spoonbill, which feeds in shallow water, could struggle to find places to feed.
• Newcomers: warming has already brought the nine-banded armadillo. Invasive species may follow, such as Burmese pythons spreading north from Everglades National Park. Storms also bring invaders, and the park watches for them as hurricanes increase.
• Unknowns: changes in habitat and the food web ripple through the whole wildlife community in ways not yet known.

Wildfire, from the park's Climate Futures Summary: fire is natural in many forests, woodlands and grasslands, but extreme fires can transform ecosystems, endanger lives, foul the air and damage infrastructure. Climate change intensifies the heat behind wildfire and alters the fuel. Under the highest emissions scenario, large fires (more than 50 km², 20 sq mi) could become up to three times as frequent in forests of the Atlantic Coast, Florida and the Gulf Coast by 2050.

A ranger teaches about our impact on the environment. NPS.

Hotter already

The two hottest years before 2000 were 1990 and 1998; both have been exceeded in 4 years since 2000.

What it means for your visit

• Heat: bring water and a salty snack on summer hikes.
• Check first: the park's Alerts and local weather.
• Storm closures: the park closes ahead of tropical storms so staff can evacuate, and stays closed through cleanup. As storms grow more frequent, so will closures.
• Changing scenery: erosion, shifting plant life, drought and flooding will change how the park looks.
• Ranger tip: at high tide, water often makes the Fort George Road entrance to Kingsley Plantation impassable — use Palmetto Avenue.

What you can do

• Talk about climate change with friends and family; your voice matters most with people who trust you.
• Join or start a local climate action group.
• Volunteer with ecological groups or parks like Timucuan — any work that helps ecosystems is climate work.
• Try conservation at home.

Sources

Based on "Climate Change in Timucuan Preserve," National Park Service, quoting the park's Climate Futures Summary (citing Jolly and others, 2015; Westerling, 2016; Barbero and others, 2015); a work of the United States government in the public domain.