Everglades Ecosystems

This week and next we’re taking a look at the largest subtropical wilderness in America, the Everglades. What we now know as Everglades National Park is just a fraction of the original Everglades, and unfortunately, almost daily it becomes a larger percentage of what of remains today. While what remains is an incredibly diverse variety of habitats, each with their own plants and animals, it is not without its challenges. We’ll explore what’s so special about this place as well as what’s going wrong there.

In its former glory, the Everglades was a huge watershed. Water flowed south from areas north of Lake Okeechobee and drained to the east, west, and south. Some of the water flowed east and west into the Atlantic Ocean and Gulf of Mexico, respectively, through traditional rivers and streams. Some water flowed out through the slow-moving “River of Grass”, as the Everglades became known as. Where the water goes and how much gets there determines the many different ecosystems.

Many other factors go into building an ecosystem, including geology and climate. To me, what gives an ecosystem its character is its plant life. The Everglades has quite the cast of characters, with grasses inhabiting the freshwater sloughs and marl and coastal prairies. Marl prairie is grassland of thin soil formed on top of limestone bedrock. The soil is high in calcite and the bedrock may be exposed in some areas. Rainwater becomes acidic as it dissolves plant material, and even a weak acid can easily dissolve limestone. The bedrock here is very porous. Marl prairies drain slowly.

Marl prairie (Florida Museum of Natural History)

Freshwater sloughs are main arteries for water flowing to the sea. The water moves very slowly and is very grassy. The sloughs are dotted with “islands” of trees and are bounded by the higher and drier marl prairies.

Freshwater slough (NPS)

Mangrove forests line the channels and rivers in the coastal and estuarine areas of the Everglades. Mangroves buffer the coast from storms, collect sediment to form new land, and harbor a vast array of birds, reptiles, mammals, and fishes. See my earlier blog post for more details.

Mangroves (NPS)

Hardwood hammocks are dense wooded areas on slight rises. Temperate and tropical tree species mingle here, and because the surrounding lowlands are either wet or not land at all, fire rarely reaches here. The dense canopy creates a dark and humid environment where ferns thrive.

Hardwood hammock (NPS)

Pine rocklands form on high ground around exposed limestone bedrock. These forests are less dense than hardwood hammocks. Fire keeps the understory open and hardwoods at bay.

Pine rockland (NPS)

Marine areas of Everglades National Park also have plant communities. Seagrasses stabilize the bottom, trap sediments, provide a nursery for fishes, and feed underwater herbivores. Lobsters, crabs, shrimp, corals, and sponges are also found offshore.

Florida Bay marine habitat (NPS)

Next week we'll look more at the plants and animals of the Everglades, as well as challenges the region faces. Information and photos this week come from the National Park Service.