Habitat

The Indian River Estuary is the most bio-diverse habitat in North America.

About

The Indian River Lagoon National Estuary has more species of animals and plants than any other estuary in North America, including over 2,200 animal species and over 2,100 plant species. Because the Indian River Lagoon Estuary is located where temperate and tropical zones overlap and it's brackish water is fed by fresh and salt water sources, it is uniquely situated to support a wide variety of resident and migratory plants and animals.

Dolphin in the Banana River

Habitat

Seagrass

Some of the most extensive sea grass beds of the estuary, including manatee grass, turtle grass, shoal grass and the threatened Johnson's sea grass are only found in the Indian River Lagoon Estuary. These sea grass communities provide spawning, nursery, and foraging habitat for many aquatic species, including spotted sea trout, redfish, snook, tarpon, mullet, sheepshead, pompano, seahorses, blue crabs, hermit crabs, pink shrimp, scallops, clams, marine worms, marine snails, and other crustaceans. Manatees, dolphins, otters and juvenile sea turtles are commonly found foraging in the estuarie's seagrass.

Oyster Bars

Oyster bars, made up of the filter-feeding mollusks, help cleanse the estuary and stabilize shorelines. They also provide habitat for the fry, shrimp, mollusks and crustaceans that support the estuarie's shorebirds and waterfowl.

Salt Marshes

Salt marshes with their associated tidal creeks and mud flats consist of such marsh plants as smooth cordgrass, saltgrass, saltwort and glasswort. Salt marshes also provide abundant food and cover for a wide variety of resident and transient wildlife, including alligators, snakes, marsh rabbits, waterfowl, shore birds and crustaseans.

Mangroves

The estuarie's mangrove habitats include three true species of mangrove trees. These trees play a vital role in the food chain of the Indian River Estuary and also in the growth and development of many aquatic organisms. Microorganisms, which feed on decaying mangrove leaves, become food for shrimp, crabs, snails, and worms. They in turn become food for many species of fish, which in turn, support numerous wading birds in the refuge.

Mangrove trees contain several different communities of life from their roots to their canopy. The distinctive roots of the mangroves provide habitat for oysters and barnacles and sheltering habitat for many species of juvenile fish. The trunk and branches of the tree provide habitat for periwinkle snails, mangrove crabs, and mangrove snakes. The tree canopies provide nesting habitat for many species of birds.

Mangrove Species

Each of the three mangrove species found in the Indian River Estuary have unique adaptations to survive in the harsh saltwater environment.

Red Mangroves

Red mangroves are most common along the shorelines and basins. They have prop roots that help provide oxygen, exclude salt and provide a stable foundation. Their distinctive cigar-shaped propagules are actually seeds that have already germinated before hitting the ground. They excrete salt through a system of sacrificial leaves.

Black Mangroves

The black mangroves, predominant on natural islands (including Pelican Island) just above the tide line, have a lateral root system with pneumatophores that thrust above the ground, giving the appearance of standing on a bed of spikes. They excrete salt through the underside of their leaves.

White Mangroves

The white mangrove is found further ashore and excretes salt through pores at the base of their leaves.

Endangered Species

As a result of multiple causes and threats, many species endemic to the estuary have become extinct, endangered, or threatened. The Indian River Lagoon National Estuary is home to at least 14 federally threatened or endangered species. It also supports 45 species listed by the State of Florida as either threatened, endangered, special concern, or commercially exploited.

Web Links

• EPA An Introduction to a National Treasure

References