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Natural Communities of Estero Bay Aquatic Preserve Quick Topics

Estero Bay contains ten natural community types. Although overlap between the different communities often occurs, they remain distinct community types.

Macroalgae Algal beds are characterized as large populations of non-drift macro or micro algae. These beds of attached algae, along with seagrasses, make up the Submerged Aquatic Vegetation (SAV) found within the bay. Species consist of Caulerpa prolifera, C. mexicana, and C. sertularoides and are mostly concentrated in the middle portions of the bay, often found along the interface between seagrass beds and unconsolidated substrate. The invasive C. taxifolia has not been recorded within the aquatic preserve.

Beach dunes are characterized as a wind-deposited foredune and wave-deposited upper beach that are sparsely to densely vegetated with pioneer species, especially sea oats (Uniola paniculata). The only pocket of beach dune located within the aquatic preserve is located within Lovers Key State Park.

Estero River

Blackwater streams are characterized as perennial or intermittent seasonal watercourses originating deep in sandy lowlands where extensive wetlands with organic soils function as reservoirs, collecting rainfall and discharging it slowly to the stream. The tea-colored waters are laden with tannins, particulates, and dissolved organic matter and iron derived from drainage through swamps and marshes. They generally are acidic (pH = 4.0 - 6.0), but may become circumneutral or slightly alkaline during low-flow stages when influenced by alkaline groundwater. Hendry Creek, Mullock Creek, Estero River, Spring Creek, and Imperial River all fit into this category and flow into Estero Bay.


Coastal berms are short forest or shrub thicket found on long narrow storm-deposited ridges of loose sediment formed by a mixture of coarse shell fragments, pieces of coralline algae, and other coastal debris. These ridges parallel the shore and may be found on the seaward edge or landward edge of the mangroves. They range in height from one to 10 feet. Structure and composition of the vegetation is variable depending on height and time since the last storm event. There are three main areas where this type of accretion is occurring within the aquatic preserve. The largest is on the south side of New Pass. The other two are located at the entrance to Big Hickory Pass.

Red mangroves at low tide

Mangrove swamps are characterized as dense, low forests occurring along relatively flat, intertidal and supratidal shorelines of low wave energy along southern Florida. These are located southeast of the mouth of Mullock Creek, at the mouth of Estero River, along Spring Creek, west of the mouth of Imperial River, and scattered in other small pockets around the bay. Birds utilize mangrove swamps as nesting habitat and fish use their roots as nursery grounds and as protection from predators.


Mollusk reefs are characterized as expansive concentrations of sessile mollusks occurring in intertidal and subtidal zones to a depth of 40 feet. In Florida, the most developed mollusk reefs are generally restricted to estuarine areas and are dominated by the American (or Virginia or Atlantic) oyster (Crassostrea virginica). In a 2009 benthic study, the Conservancy of Southwest Florida found a large complex of oyster reefs in the northeastern portion of the bay, with small isolated reefs occurring southward. Additionally, the Florida Gulf Coast University Vester Field Station has an ongoing restoration program focusing on the creation of mollusk reefs within the Caloosahatchee River, San Carlos Bay and Estero Bay.

Flooded salt flats

Salt marshes are a largely herbaceous community that occurs in the portion of the coastal zone affected by tides and seawater and protected from large waves. The width of the intertidal zone depends on the slope of the shore and the tidal range. Salt marsh may have distinct zones of vegetation, each dominated by a single species of grass or rush. Flooding frequency and soil salinity are the two major environmental factors that influence salt marsh vegetation. Needle rush (Juncus spp.) and saltmarsh cordgrass (Spartina alterniflora) both tolerate a wide range of salinities, but cordgrass is found where the marsh is flooded almost daily, whereas needle rush is found where the marsh is flooded less frequently. Although there is well over a thousand acres of salt marsh community within the Estero Bay area, only a small portion falls within the aquatic preserve.

Turtle grass and shoal grass

Seagrass beds are characterized as expansive stands of vascular plants. This community occurs in subtidal (rarely intertidal) zones, in clear, coastal waters where wave energy is moderate. Aquatic preserve personnel monitor SAV species within the bay. The five most common are turtle grass (Thalassia testudinum), manatee grass (Syringodium filiforme), shoal grass (Halodule wrightii), star grass (Halophila engelmannii) and paddle grass (Halophila decipiens). The Conservancy of Southwest Florida also documented small patches of widgeon grass (Ruppia maritima) near the mouth of Spring Creek and in the New Pass area during its 2007 study. Moreover, the study also found that significant differences in the morphometrics of turtle grass throughout Estero Bay: the northern area had the lowest biomass. Overall, seagrasses within the estuary have begun a slight resurgence after decades of decline, starting during the drought conditions that occurred during 2006-2007.


Sponge beds are characterized as dense populations of sessile invertebrates of the phylum Porifera, Class Demospongiae. Although concentrations of living sponges can occur in marine and estuarine intertidal zones, sponge beds are confined primarily to subtidal zones. There is a small patch of sponge bed located in Estero Bay, bayside just north of Big Carlos Pass at the entrance to Buccaneer Lagoon. There are less than one acre of sponge beds in Estero Bay, but they are present in several places throughout the bay. Sponges can occur outside of sponge beds in areas of unconsolidated substrate where they are an important component of the foraging habitat utilized by endangered Kemp's ridley sea turtles.

Unconsolidated substrate

Unconsolidated substrates are characterized as expansive, relatively open areas of subtidal, intertidal, and supratidal zones which lack dense populations of sessile plant and animal species. Unconsolidated substrates are unsolidified material and include coralgal, marl, mud, mud/sand, sand or shell. This community may support a large population of infaunal organisms as well as a variety of transient planktonic and pelagic organisms. This community accounts for over half of the substrate within the bay and is found not only in deeper waters such as channels but also in some of the shallowest and intertidal portions of the bay, where SAV are not found.

Last updated: December 29, 2015

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