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Publication #ENY653

Coastal Wetlands of the Indian River Lagoon1

Jorge Rey and C. Roxanne Rutledge2

Introduction

Coastal wetlands (salt marshes and mangrove forests) are important components of estuarine and coastal systems. These habitats often have extremely high production that fuels both terrestrial and aquatic food webs. In addition, wetlands contribute to estuarine water quality by removing excess nutrients and pollutants originating in the uplands before they reach the estuary. Wetlands provide important habitats for a wide variety of organisms including invertebrates such as crabs and shrimp, fish, birds and others (Figure 1), and provide protection against coastal erosion Many commercially important estuarine species rely on these habitats to succesfully complete their life cycle.

Figure 1. 

Coastal wetlands are important nursery habitats.

Indian River Lagoon Wetlands

Coastal wetlands along the Indian River Lagoon are relatively young, having developed less than 6,000 years ago on shallow areas of past and present inlets. On the north end of the lagoon, marshes are mostly populated with grassy, salt tolerant species (halophytes) such as smooth cordgrass (Spartina alterniflora) in the low marsh, and salt grass (Distichlis spicata), saltwort (Batis maritima, Figure 2), perennial glasswort (Salicornia virginica, Figure 3), annual glasswort (Salicornia bigelovii), and black rush (Juncus roemerianus) in the high marsh. In some areas, a few mangroves, usually black mangroves, are found among the high marsh vegetation.

Figure 2. 

Saltwort, Batis maritima.

Figure 3. 

Perennial glasswort, Salicornia virginica.

In the south, wetlands are either dominated by mangroves, with red mangroves (Rhizophora mangle) along the shore, and black mangroves (Avicennia germinans) and white mangroves (Laguncularia racemosa) in the upper marsh, or are of a mixed character, with red mangroves and/or cordgrass at the water's edge, and a mix of herbaceous halophytes including Salicornia virginica, S. bigelovii, and Batis maritima mixed with black mangroves in the upper marsh.

In some impounded areas with no connection to the lagoon, single-species stands of red mangroves often replace the natural high marsh vegetation.

Mangroves

Mangroves are essentially tropical trees that inhabit coastal areas. There are approximately 54 species of true mangroves worldwide characterized by the following attributes:

  • Morphological adaptations, such as specialized roots, that adapt them to their environment.

  • The ability to exclude or filter out salt.

  • Seeds germinate while still on the parent plant.

  • Restricted to the mangrove environment.

  • Taxonomic isolation(no close terrestrial relatives at least at the generic level).

There are three species of true mangroves in Florida: the red mangrove (Rhizophora mangle, Figure 4), the black mangrove (Avicennia germinans, Figure 5), and the white mangrove (Laguncularia racemosa, Figure 6).

Figure 4. 

Red mangrove, Rhizophora mangle.

Figure 5. 

Mixed marsh of black mangroves and herbaceous vegetation.

Figure 6. 

White mangrove, Laguncularia racemosa.

The buttonwood (Conocarpus erectus, Figure 7) is not a true mangrove, but it is often associated with white mangroves in the higher elevation areas.

Figure 7. 

Buttonwood, Conocarpus erectus.

Footnotes

1.

This document is Fact Sheet ENY-653, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Serivce, Institute of Food and Agricultural Sciences, University of Florida. Date first published: August 2001. Reviewed: January 2009. Please visit the EDIS Web site at http://edis.ufl.edu.

2.

Jorge R. Rey, professor, and C. Roxanne Rutledge, assistant professor, Entomology and Nematology Department, Florida Medical Entomology Laboratory, Vero Beach, Cooperative Extension Service, Institute of Food and Agricultural Sciences.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.