Yellow River Marsh Aquatic Preserve

The aquatic preserve contains different types of forested wetlands, and there are extensive marshes at the mouths of Yellow River and Weaver River that transition from estuarine tidal marsh to freshwater marsh. Continuing into the bay, the aquatic preserve includes seagrass beds and other benthic communities.

Wet Flatwoods

Wet flatwoods have a somewhat open canopy of scattered pine trees (Pinus spp.) with either a thick, shrubby understory and very sparse ground cover, or vice versa. During the rainy season, water accumulates on the surface, inundating the flatwoods for one or more months per year. An estimated fire return interval of three to 10 years is needed to inhibit succession to a more hardwood dominated forest. The wet flatwoods of Yellow River Marsh Aquatic Preserve are in mostly good condition with some of the denser areas in current need of fire application. These areas have minimal acreage, and much of the adjacent managed lands are also in need of fire. These locations may be added to the planned burn list from other management agencies.

Wet Prairie

Wet prairie is an herbaceous community, typically dominated by dense wiregrass (Aristida stricta var. beyrichiana), found on continuously wet, but not inundated, soils. Wet prairies in northern Florida are some of the most diverse communities in the United States, with an average of more than 20 species per square meter in some places and more than 100 total species in any given stand.

An estimated fire return interval of two to three years and little soil disturbance are necessary to maintain wet prairies. In the absence of fire, shrubs and trees invade and shade out the herbaceous species. Small alterations to the soil surface in wet prairies can permanently alter the hydrology, causing major changes in species composition which may require expensive restoration to repair. Wet prairie in Yellow River Marsh Aquatic Preserve remains in good condition.

Floodplain Swamp

Floodplain swamp is a forested, permanently or frequently flooded community adjacent to stream and river channels and in depressions and oxbows within floodplains. The canopy is generally dominated with trees such as bald cypress and tupelo, and may contain other trees, to a lesser extent, that are able to withstand frequent inundation. Floodplain swamp communities provide important wildlife habitat, contribute to flood attenuation, and help protect the overall water quality of streams and rivers. Floodplain swamp and other wetland forested mixed areas in Yellow River Marsh Aquatic Preserve are in good condition with little development or alterations. Several invasive species have been notated within or adjacent to aquatic preserve boundaries.

Floodplain Marsh

Floodplain marsh is a wetland community occurring in river floodplains and dominated by herbaceous vegetation and/or shrubs. Most floodplain marshes are freshwater (salinity less than 0.5 parts per thousand); however, saltwater may influence marshes near the mouths of rivers (freshwater tidal marsh variant) (FNAI, 2010), such as the case in Yellow River Marsh Aquatic Preserve. This natural community in Yellow River Marsh Aquatic Preserve is in good condition and receives adequate water fluctuation to maintain hydrology.

Salt Marsh

Two principal marsh plants, salt marsh cordgrass and black needlerush, range throughout Florida and are found in Yellow River Marsh Aquatic Preserve. Cordgrass is found where marsh is flooded almost daily, and needlerush is found where the marsh is flooded less frequently. One rare plant, beaked spikerush, and one rare reptile, the Gulf saltmarsh snake, are found in salt marsh in the aquatic preserve. Key bird species found in salt marsh of Yellow River Marsh Aquatic Preserve include the Louisiana seaside sparrow, which depends on the marsh throughout its entire life cycle, and the marsh wren, which relies on the marsh for breeding grounds. Additional bird species that frequent salt marsh habitat within the aquatic preserve include the black rail, tricolor heron, white ibis and little blue heron.

Estuarine Unconsolidated Substrate

Yellow River Marsh Aquatic Preserve is composed largely of estuarine unconsolidated substrate, some of the most widespread natural communities in the world. Throughout Florida, estuarine unconsolidated substrate communities can vary in origin based on the surrounding plant material. Four kinds of unconsolidated substrate - mud, mud/sand, sand and shell - are found throughout the coastal regions of Florida, but Yellow River Marsh Aquatic Preserve mostly includes the composition of mud and mud/sand. Much of this unconsolidated substrate is attributed to sedimentation from rivers influencing the watershed.

The condition of this natural community is good, but the sedimentation is an issue, particularly to other natural communities such as seagrass beds and mollusk reef. This sedimentation could be minimized with additional funding for paving of roads. The addition of shell to the system has been beneficial in recent years and will continue to provide suitable substrate for oyster growth.

Estuarine subtidal zones are important feeding grounds for many bottom-feeding fish in the aquatic preserve, such as spot, catfish, and the federally threatened Gulf sturgeon; and intertidal and supratidal estuarine zones are important feeding grounds for many shore birds and invertebrates.

Seagrass Beds

Seagrass beds mostly occur in subtidal zones, in clear, coastal waters where wave energy is moderate. The species of seagrass that occurs in Yellow River Marsh Aquatic Preserve is widgeon grass. It can survive in a wide range of salinities giving it a broad aquatic distribution. Many of the bayous along the eastern boundary of the aquatic preserve are abundant with widgeon grass and provide essential habitat to a variety of ecologically, recreationally and commercially important species.

A similar type of submerged aquatic vegetation in Yellow River Marsh Aquatic Preserve is tapegrass (also known as eelgrass). It is not a seagrass, as it is a freshwater plant. Due to the freshwater output from Yellow River, large patches of tapegrass can be seen in this mostly estuarine system. The tapegrass in Yellow River Marsh Aquatic Preserve is in good condition with excellent coverage, minimal prop scarring, and providing submerged stabilization around marsh habitat near the mouth of the Yellow River, as well as on the western boundary of the aquatic preserve.

Mollusk Reef

In Florida, most mollusk reefs are generally restricted to estuarine areas and are dominated by the American oyster. Within the collage of the substrate, numerous other sessile and benthic invertebrates live among, attached or within the community. In Yellow River Marsh Aquatic Preserve, the most common are oyster drills, polychaetes, barnacles, blue crab and mud crab. Many fish frequently occur near or feed among the mollusk reefs in and around Yellow River Marsh Aquatic Preserve, such as gobies, killifish and striped mullet.

Mollusk reefs that are exposed during low tides are frequented by a multitude of shorebirds, wading birds, raccoons and other vertebrates.

Sedimentation and other factors have led to a decline in oyster reef acreage in Yellow River Marsh Aquatic Preserve. Once a highly productive community for Yellow River Marsh Aquatic Preserve and surrounding waters, there is focus for oyster reef restoration in subtidal and intertidal areas to bring back to historical conditions. Currently this natural community has minimal presence in the aquatic preserve.

Several intertidal and subtidal oyster bed restoration projects have been implemented, and more are planned.