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Indian River Lagoon Aquatic Preserve Management Issues - Loss of Natural Community Function and Biodiversity Quick Topics

Habitats within the IRLAP System consist primarily of shallow water communities which comprise some of the most diverse and productive ecosystems in the United States. Major ecological communities present include tidal wetlands, mudflats, oyster reefs, seagrass beds and islands.

While many of these communities within and adjacent to the IRLAP System continue to be highly diverse and productive, they have suffered impacts as the result of growth and development in the region. These impacts threaten long-term sustainability of the IRLAP System's natural resources. There have been losses to wetlands and seagrass acreage, impacts to oyster reef extent and function, and an influx of non-native, invasive plants and animals. In addition, there is the potential for additional losses of these habitats in the future from incompatible land use practices and public use.

Significant habitat restoration efforts are underway and additional opportunities exist to conserve and restore species diversity within the IRLAP System. In the last two decades, several thousand acres of impounded coastal wetlands, originally altered to control mosquitoes, have been reconnected to the IRL. Research and monitoring studies have determined that upon reconnection to the surrounding marsh, these impacted coastal wetlands are able to rapidly recruit native vegetation and exhibit significant increases in the number of fish species.

Despite their manmade origins, spoil islands have become an important biological component of the IRL. Numerous species of native fish, invertebrates, reptiles, birds, and mammals inhabit the spoil islands, and the spoil islands support the majority of bird rookeries in the IRLAP System. However, without a well-developed vegetated community, spoil islands can be prone to infestation by invasive exotic species.

Seagrass habitat within the IRLAP System has suffered substantial loss over the last several years. The most recent data indicates seagrass coverage has declined up to 90 percent in portions of the IRLAP System due to the 2011 Superbloom. This negated a near decade-long net increase of seagrass throughout the IRL. Investigations are ongoing to determine the factors responsible for the recent collapse in seagrass coverage.

Oysters are an example of a keystone species in coastal ecosystems such as the IRLAP System. Oysters function as filter feeders, helping to improve water quality. Oyster reefs help stabilize shorelines, bottom habitats and sediments and they provide refuge and essential intertidal habitat for juvenile fishes and other wildlife (e.g., shrimp, crabs, red fish, sea trout and wading birds). There is a need to determine the relative importance of siltation, disease and altered water quality to prioritize efforts to conserve this valuable resource. The expansion of oyster habitat restoration efforts in the IRLAP System is currently being initiated.

Management strategies include:

  • Create a waypoint list (including date, species, and observer) for collected/observed rare and listed aquatic species.
  • Create a map through GIS with species sighting data overlaid on the Florida Natural Areas Inventory natural lands map.
  • Annually update the species list for the aquatic preserves and post on the IRLAP website.
  • Summarize annual monitoring data for bird rookeries and shorebird nesting.
  • Create a report and maps detailing distribution of diamondback terrapins and recommendations for their conservation.
  • Complete biannual seagrass monitoring at all transect locations.
  • Design a non-regulatory, voluntary research/collection application form to help the IRLAP manager document research monitoring, and collection/harvest being conducted within the IRLAP System.
  • Continue and expand the Shoreline Restoration Project.
  • Continue and expand spoil island enhancement through the Spoil Island Project.
  • Continue and expand shellfish restoration projects.
  • Conduct routine exotic species removal on spoil islands.
  • Assist other agencies in controlling non-native plant and animal species.

Wood storks nesting on a spoil island A wood stork rookery on a spoil island


Diamondback terrapin nesting A diamondback terrapin digs a nest


Volunteers planting marsh grass on a spoil island Volunteers planting marsh grass to stabilize the shoreline of a spoil island

Indian River Lagoon Aquatic Preserves

If you want to help preserve the Indian River Lagoon, consider joining Friends of the Spoil Islands at http://friendsofspoilislands.org.

Last updated: November 03, 2016

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