There are over 100 estuaries along the U.S. coastline offering very diverse habitats depending on location. Habitats of the Gulf of Mexico can be found throughout the Gulf states and are unique to the area; have fun exploring and learning!
The Gulf of Mexico is world known for its beautiful, white sandy beaches. Beaches are dynamic habitats found at the interface between the land and open ocean. The sand in the northern Gulf of Mexico is composed primarily of quartz sand, which is derived from the weathering of continental rock. It has traveled from as far away as the Appalachian Mountains. Sand is always in motion due to the constant influence of the wind and waves. During the summer, gentle wave action deposits sand onto the beach resulting in an accretion of the beach face. Conversely, winter storms transport sand away from the beach where it accumulates on offshore sand bars. Sand is also transported parallel to the shore throughout the year via longshore currents. In addition to these long-term processes, dramatic changes to the beach can also occur during the course of a single day as a result of strong storms and hurricanes.
As a consequence of the continuously changing environment, the diversity of animals on our outer beaches is low compared to other marine habitats. Those animals that make the beach their home are specialized to live in this rigorous and ever-changing environment. Clams, worms and snails are able to bury themselves in the sand, thus escaping the pounding waves above. Sandpipers, plovers, gulls and terns are commonly found foraging for fish and invertebrates in the surf.
When one thinks of the Gulf of Mexico, coral reefs in Florida may
come to mind.
Coral reefs are calcium carbonate structures produced by living organisms. These symbiotic zooxanthellae are single celled plants that live in the tissue of animals. Acoralline algae is also an important contributor to the structure of the reef system.
Coral reefs can be found in marine waters with little to no nutrients in the water. In fact, they don't like heavy sediment inputs that may be found near deltaic river systems. The Gulf of Mexico has both shallow and deep-water reefs. They are distinctly different in the northwest compared to southeast Gulf of Mexico.
There are many types of reefs. Influences that shape them and drive their ecology include water depth, sunlight, salinity, temperatue, local geology, and marine plants and animals to name a few. Coral reef habitats serve as biodiversity "hotspots." – Flower Garden Banks is the northernmost tropical reef in the U.S.
Dune habitats are characterized by rows of wind-built sand mounds that are like sand bars that form on land. Primary dunes are located just behind the beach face and are subject to strong winds and storm waves. Dunes provide sand reserves for beaches and serve to buffer inland habitats from the impacts of the open ocean. Animals and plants that live in these harsh conditions must contend with a near-constant onslaught of salt spray and thermal stress. Common colonizers of primary dunes include sea oats, bunch grass, and beach grass. The roots of these species bind sand together and help to stabilize dunes. Secondary dunes are located inland of the primary dune field and are generally older and more stable than primary dunes. They support larger and more permanent flora such as saw palmetto, pines, and scrubby shrubs and oaks.
Sand dunes provide niches for uniquely adapted plants and animals including many endangered species. Several subspecies of the endangered beach mouse make their home in the dunes along the gulf coast. Threatened and endangered sea turtles lay their eggs among the dunes on barrier islands along the Gulf coast.
More information about these endangered species can be found at: http://www.nps.gov/pais/naturescience/kridley.htm
Nothing conjures up a more romantic notion than paddling a canoe through still waters among cypress trees. These forested freshwater wetlands occur along the Gulf Coast and include bottomland hardwood forests and swamps. The wetlands are made up of wet-tolerant, broad-leaved and needle-leaved deciduous trees including gum, cypress, and oak species. A “Bottomland hardwood” forest is a wetland areas associated with large river systems and occur directly adjacent to a river or tributary channel. “Swamps” are typically located in backwater areas of larger river basins where standing water accumulates and remains for weeks to months. These wetlands are often further named based on the dominant trees that occur in them (for example, cypress swamps or tupelo gum swamps).
The type of soils and the frequency and duration the wetland is inundated by water, are the primary factors that determine the wetland forest’s community composition and structure. Additionally, the rich organic material that accumulates on the forest floor can provide an essential source of minerals and nutrients for downstream ecosystems, such as estuaries.
Gulf Coast forested wetlands provide food and shelter for a wide variety of native animals. Invertebrates such as worms, insects, crustaceans, and molluscs feed upon organic debris and are the primary consumers of the wetland food chain. Forested wetlands also provide feeding and breeding habitats for fishes, amphibians, and reptiles. They are a reliable water source for a variety of wading birds and mammals. Endangered mammals such as the Florida panther, mangrove fox squirrel, black bear and mink depend on forested wetlands and other wild habitats for their survival.
Forested wetlands also help filter fresh water and absorb floodwaters. Despite their high ecologic and economic values, forested wetlands of the Gulf Coast are threatened by human activities including draining, pollution, logging, mining, flood plain alterations, and introduced invasive plants.
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Freshwater marshes are wetland communities dominated by a wide assortment of herbaceous plant species, with few trees or shrubs. They occur in saturated soils in areas of variable water depths and periods of inundation. Generally, freshwater marsh habitat occurs in deeper water and is characterized by tall emergent and floating-leaved plant species. Freshwater marshes occur within flatwoods depressions, along shallow lakes, river shorelines, and scattered in open areas within forested wetland.
Portions of freshwater lakes, rivers, and canals are dominated by floating-leaved plants such as lotus, spatterdock, duck weed, and water hyacinths. Freshwater marshes are common features of many river deltas where distributary waterways discharge into estuaries. Many subcategories of this habitat, such as sawgrass marsh or maidencane prairie, have been described and named based on their dominant plant species.
As one of the most ubiquitous and widespread wetland types along the Gulf Coast, freshwater marsh habitats are subject to a wide array of threats and alterations. The hydrology of these systems can be modified or fragmented through ditching, diking, or groundwater withdrawal for municipal and agricultural purposes. Alteration of adjacent habitats for agriculture and urban/suburban development can also negatively impact these systems and increase vulnerability to invasive species. Many freshwater marshes in both agricultural and urban settings receive nutrients from discharges of stormwater management systems which may lead to substantial changes in plant community composition and associated animal changes.
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Most people probably know of a nearby creek, stream, or river. Often, these bodies of water have been altered with concrete bottoms, rocks or rip-rap lining the sides, or piped through culverts under structures like roads or bridges. Natural, unaltered stream habitats contain pools, riffles, and runs. There is an assemblage of more than twenty habitat types that describe the stratification of streams and allows one to evaluate the biological or physical attributes of the water body. Some of these include: sediment type and quality, vegetative cover, and bank conditions. Habitat type and quality can be used as an indicator of the health of fish and other aquatic fauna populations in the water.
Plant and animals species may become specialized to stream area and type. Certain freshwater mussels require Riffles or areas of swifter flowing water, where the surface is turbulent. Some fish species may live in Glides or slow moving areas in the stream, where the surface is smooth.
Objects such as logs, root wads, boulders or stream banks can cause backwater pools to form as water swirls around the obstacle. Plunge pools are formed where water falls over an obstacle, slowing down the velocity of the stream. The falling water scours a hole where juvenile and adult fish often hide. The vegetation associated with the stream, along its banks and into floodplains is called the Riparian Zone. Some important indices of fish habitat, such as pool depth and percent canopy cover, are sensitive to stream size. In smaller streams of forested landscape, good habitat is associated with a riparian canopy of at least 80%.
Streams that flow together into a common source such as a lake, bay, or Gulf comprise an area known as a watershed.
McCain, M., D.Fuller, L.Decker and K.Overton. 1990 . Stream habitat classification and inventory procedures for northern California. FHC Currents. No.1. U.S. Department of Agriculture. Forest Service, Pacific Southwest Region.
Hawkins, C.P., and 10 coauthors. 1993. A hierarchical approach to classifying stream habitat features. Fisheries 18(6): 3-12.
Primarily known in Florida along the Gulf coast, mangrove forests occur in tropical and subtropical regions along low-energy, tidally influenced estuarine and marine shorelines. This type of habitat is dominated by mangrove trees and other shrubs that have adapted to life in wet soils, salty habitats, and periodic submerging by tides. Mangroves provide habitat for a diverse set of plants and animals. They help maintain the shoreline and control coastal erosion.
Three species of mangrove (red, black, and white) and the buttonwood occur along the U.S. Gulf Coast. All of these species may grow along the same shoreline, but may occur in different areas within the tidal zone. This zonation is determined by tidal changes, elevation of the land, and the salinity of the soil and water. Because of their sensitivity to sub-freezing temperatures, mangroves in the continental United States are limited to the coastal Florida peninsula and isolated areas of the gulf coast of southern Louisiana and south Texas.
Red mangroves are found along the water's edge, with full exposure to tidal variation and winds. They are well adapted to these conditions with prop roots extending from the trunk and branches. These tangles of root systems increase stability as well as capturing sediments from the surrounding water. Black mangroves live on higher ground and have specialized root structures which stick up out of the soil like straws for breathing called pneumatophores. These root adaptations are used to supply oxygen to the underground roots that are often in anaerobic (oxygen-free) sediments. White mangroves, often lacking special root adaptations, occur in the interior of the mangrove forest, followed by the buttonwood in the upland transitional area. Mangrove trees help maintain the shoreline and control coastal erosion.
The mesh of mangrove roots serves as a valuable habitat and nursery area for many species or shrimp, crabs, and fishes, including those important to commercial and recreational fishing industries. These habitats provide a rich source of food while also offering refuge from predation. Mangroves also provide a habitat for many bird species. Wading birds (e.g., herons, egrets, bitterns, spoonbills, limpkins, ibis) visit mangroves and adjacent shallow waters and mudflats in search of food. Floating and diving birds (e.g., ducks, grebes, loons, cormorants, pelicans) feed on fishes, plant material, and invertebrates of the mangrove habitat. Birds of prey (e.g. southern bald eagle, osprey, peregrine falcon) also depend on mangrove habitats for food and shelter. Many of these bird species also roost or nest in the mangrove tree canopy.
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This system encompasses a mosaic of woody vegetation present on barrier islands and near-coastal strands along the northern Gulf of Mexico, from the Florida panhandle to southern Mississippi. Examples may include forests and/or shrublands that are found in somewhat more protected environments than East Gulf Coastal Plain Dune and Coastal Grassland. Maritime forest areas include relatively stabilized coastal dunes, sometimes with a substantial shell component. Vegetation structure and composition are influenced by salt spray, extreme weather events, and the distinctive climate of the immediate coast. Stands may be dominated by a variety of needle-leaved and broad-leaved evergreen trees, including Pinus clausa, Pinus elliottii var. elliottii, Pinus palustris, Quercus virginiana, Sabal palmetto, Carya glabra, and Carya pallida. Wetland inclusions may be dominated by Taxodium ascendens and Magnolia virginiana. The most heavily salt-influenced examples may appear pruned or sculpted.
- Comer, P., D. Faber-Langendoen, R. Evans, S. Gawler, C. Josse, G. Kittel, S. Menard, M. Pyne, M. Reid, K. Schulz, K. Snow, and J. Teague. 2003. Ecological systems of the United States: A working classification of U.S. terrestrial systems. NatureServe, Arlington, VA.
- EPA [Environmental Protection Agency]. 2004. Level III and IV Ecoregions of EPA Region 4. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR. Scale 1:2,000,000.
The Gulf of Mexico is an oceanic basin containing open water habitat with a surface area of 1.5 million square kilometers. Scientists have learned that there is quite a diversity of plant and animal species based on depth of water, sunlight availability, and distance from land. The Gulf of Mexico has shallow, intertidal areas, a continental shelf and slope, and deep abyssal areas.
Open water habitat refers to life found throughout the water column, however abundance and diversity decreases with increased depth. Most commercially and recreationally caught fish spawn in the epipelagic zone. Most people think of the open water habitats of the Gulf of Mexico as barren. To the contrary, coral reefs, oil seeps, and hydrothermal vents can be found.
Oyster reefs are prime, coastal habitats. As a keystone species, oysters provide habitat for an extensive array of marine life. An oyster reef can encompass 50 times the surface area of an equally extensive flat bottom. Oyster reefs contribute to improved water quality through its filter feeding capacity. They are found in Gulf of Mexico as both intertidal and subtidal reefs. Oysters are an important commercial species that people enjoy eating.
Ponds can be man-made or form naturally. They consist of a small area, no more than 1.8 m deep, of fresh, still water. Many people wonder what makes a pond different from rivers, streams and lakes? The small size and not having moving water differentiates the pond from these habitats.
Plants living in ponds reside in specific zones: above surface, aquatic, and submerged. It’s important for ponds to have plenty of sun so that plants can generate food through the sunlight (photosynthesis). Phytoplankton (algae) are the smallest plants that provide the most food and are an integral part of the food chain. Native plants are beneficial in providing a balanced habitat and invasive plants can cause harm. This website: http://www.aquahabitat.com/pond.plants.html offers a list of some North American invasive vegetation that is most threatening.
The range of animals that live or visit ponds is enormous! Amphibians, small fish and invertebrates are certain to live in ponds. Amphibians include: frogs, toads and salamanders. Examples of small fish found in ponds include: perch, pike, and stickleback. Examples of invertebrates include: pond snails, mayfly, diving beetles and dragonflies. Plenty of birds also make ponds home or visit, including: ducks, herons and kingfishers. The numbers and diversity of animals in a pond represent the health of the pond.
Life within a pond habitat is connected and everything is interdependent. Ponds must have suitable quality of water, a large enough amount of water, diverse types of food, and shelter and space for animals. Keeping ponds clean is very important for the plants and animals that live there, as well as for us since they replenish groundwater.
Riparian habitat is the assortment of (usually) native plants that occur adjacent to freshwater streams, creeks and rivers. Riparian zones are prone to flooding and associated land movement, and the plant species found in streamside zones are well adapted to this ever-changing environment. Coastal watersheds are made up of extensive stream networks that support this habitat. Healthy riparian habitat is a key element in maintaining stream conditions that support various fish populations. The following sections examine riparian systems:
Riparian systems support high levels of biological diversity (Motroni 1980) and are among the most endangered ecosystems in the United States (NRC 1992). Native riparian plant communities comprise some of the most productive wildlife habitat in North America (Motroni 1980) and are critically important to the life cycle of endangered salmonid species (FISRWG 1998). Aquatic macroinvertebrates, required prey of salmonids, are correlated with healthy riparian forests.
Riparian vegetation also provides important "ecosystem services," including sequestering pollutants and excess nutrients entering streams from surrounding landscapes. These effects are so great that regulatory agencies are increasingly recognizing that effective management of aquatic ecosystems requires effective management of the terrestrial plant communities that border these environments.
Motroni, R. 1980. "The Importance of Riparian Zones to Terrestrial Wildlife." US Fish and Wildlife Service.
National Research Council (NRC). 1992. "Restoration of Aquatic Ecosystems: Science, Technology and Public Policy." Committee on Restoration of Aquatic Systems. National Academy Press.
Federal Interagency Stream Restoration Working Group (FISRWG). 1998. "Stream Corridor Restoration: Principles, Processes, and Practices." Federal Interagency Stream Restoration Working Group (FISRWG). GPO Item No. 0120-A; SuDocs No. A 57.6/2:EN 3/PT.653. ISBN-0-934213-59-3.
Rocky shorelines are composed of solid bedrock with very little sediment. They are often exposed to tremendous forces of waves and currents. Due to their bedrock composition, they are not prone to erosion in human time scales. Rather, change on rocky shorelines occurs in geologic time, over thousands or millions of years. Rocky shorelines provide habitat to many marine organisms that have adapted to life in this harsh environment.
The plants and animals that live on rocky shorelines have adapted to very challenging conditions. A basic requirement is the ability to hang on tightly, against the constant forces of waves and currents. For example, seaweeds such as kelp hold on with root-like holdfasts, barnacles secrete “cement” and mussels anchor themselves with sticky threads. Rocky shorelines are not very prone to erosion, so they are not as vulnerable to development as shorelines formed of soft sediment.
However, the living organisms can be damaged by trampling, harvesting or pollution. Some types of seaweeds are sensitive to shading from structures such as docks, wharves and walkways. Plants and animals must be able to survive large temperature changes as well as dry conditions during the low tide. Some shelled animals can capture a small amount of water and seal it in their shells. Tide pools are unique features of the rocky shoreline. These small pools of trapped seawater can contain creatures that normally occur in the subtidal zone.
Despite the hardships of this environment, abundant nutrients are provided by cool waters and constant flushing. Plant and animal communities establish in the tidal zone to which they are best suited. This results in zones called bio-bands that can be seen clearly by the type and color of vegetation and animal life. With so many species crowded in to a fairly accessible environment, rocky shorelines provide ideal sites for marine biology education. The beauty of these ecosystems attracts tourists and recreational users alike.
Yorath, C.J. and H.W. Nasmith. 2001. The Geology of Southern Vancouver Island; a field guide.
A salt marsh habitat is a transitional intertidal wetland area between land and a bay, estuary, or other salty body of water. It is dominated by salt tolerant, rooted herbaceous plants (e.g., cord grass, needlerush, saw grass, saltwort, saltgrass and glasswort) and subject to daily tidal flooding. Species distributions are affected by biotic and abiotic variables such as elevation, substrate type, degree of slope, wave energy, competing species, and salinity.
Salt marshes rank among the most productive ecosystems on earth. Fishes, crabs, and shrimps live in salt marshes where plant stems, leaves, and roots provide food and shelter from predators. Salt marshes also provide excellent habitat for birds, with many places for feeding, reproducing and roosting.
Salt marshes have not always been regarded as valuable resources. Over half of our original salt marshes in the United States have been destroyed through the filling of marshes to create more land area for homes, industry and agriculture. Other losses were caused by ditching for mosquito control and diking to create impoundments. Fortunately, people are beginning to realize the importance of these habitats. Federal and state laws and regulations now reflect an appreciation by the general public for the function and value of marshes.
Information adapted from:
Shrub swamps are wetland communities dominated by dense, low-growing, woody shrubs or small trees and are usually evidence of some past disturbance to a different wetland type. This change in habitat type can be caused by logging, clear cutting or land clearing, siltation, fire (or lack of it), or a change in drainage patterns. Along the Gulf Coast, many shrub swamps are tangles of one species, such as black titi or willow, which form a dense, thick, nearly impenetrable canopy. Shrub swamps are a common wetland type in the region and is habitat for species including bears, tree frogs, migratory birds, and salamanders.
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Seagrass habitats occur in shallow and sheltered coastal waters anchored in sand or mud bottoms. There are true, marine seagrasses and then other plants that are referred to as submerged aquatic vegetation (SAV).
These underwater vegetated areas are highly diverse and productive ecosystems.They harbor hundreds of associated species of plants and animals. Seagrasses and SAVs are a highly important link in the food web. They are also
critical nursery grounds for many commercially and recreationally important fisheries such as shrimp, blue crab, and fish.
SUBTIDAL SAND FLATS
Subtidal sand flats are found between off-shore sandbars and seaward of the sandbar system. Exposure to high wave energy prevents fine sediments from settling and the resulting sediment is generally composed of course sand containing little organic material. Although they might appear barren, these habitats support extensive assemblages of filter-feeding bivalves, benthic (bottom-dwelling) fishes, burrowing gastropods, stomatopods, crabs, and annelid worms. Fish and marine mammals that are able to take advantage of this hidden bounty are generally well-adapted for locating prey beneath the sand. Reefs (natural and man-made), gas rigs, and hard bottom areas uncovered by scouring, support many species of fish and invertebrates.
Upland habitats include the many 'open' habitats found above the upper limits of agricultural enclosure (usually around 250 - 400 m). These include heaths, bogs, rough grasslands, and also rocky habitats such as screes and ledges, and mountain habitats. These open habitats have important interfaces with other habitats such as native woodlands and freshwaters, and support a wide range of species.
The uplands have suffered huge losses of some habitats and associated species over a long period of time. Since the 1950s, conifer plantations, acid grasslands and so-called 'improved' hill pastures have replaced many of the more natural upland habitats. There have also been reductions in the cover and quality of some of the more natural components of habitats, largely due to heavy grazing and burning pressures, but also due to atmospheric deposition.
Summary descriptions of National Vegetation Classification grassland and montane communities.
Cooper, EA (1992)
Joint Nature Conservation Committee, Peterborough (UK nature conservation, No. 14)