Throughout the year salt marshes exhibit cycles of birth, growth, and death. That may be most obvious when looking at the plants, but it also applies to animals, bacteria, and fungi, sometimes on longer and sometimes on shorter time scales. Since marshes are such productive ecosystems, what happens to all of that organic matter when something dies, be it a leaf, single-celled organism, or alligator? Detrivores are an important part of the marsh ecosystem, breaking down organic matter and cycling nutrients; in fact, in salt marshes, detrivores are the dominant consumers.
Most decaying plant matter in a salt marsh is consumed by bacteria and fungi, which are then food for larger creatures, but a host of species in the salt marsh are detrivores: snails, crabs, amphipods, nematodes, fish, and many others. Some of these, like fiddler crabs, feed by finding pieces of detritus on grains of sand and soil, while others specialize on a particular species’ remains. Gammarus palustris is an amphipod which consumes the dead leaves from salt marsh cordgrass (Spartina alterniflora). Zimmer et al. (2004) suggested a variety of detrivores were needed in any habitat type for efficient decomposition and that you couldn’t substitute one species for another- the different species contribute in different ways. Whether big or small, detrivores keep nutrients moving within the system and prevent dead organic matter from building up, and that helps salt marshes continue to be so productive.
Zimmer, M, Pennings, SC, Buck, TL and TH Carefoot. 2004. Salt marsh litter and detrivores: a closer look at redundancy. Estuaries27: 753-769.
Marsh is a type of wetland that is continuously flooded with water. Emergent-soft stemmed vegetation is present in marsh due to the saturated soil conditions. In Louisiana, there are four types of wetland marsh: freshwater, intermediate, brackish, and salt. Marshes are classified according to the salinity of the water. The location of Louisiana marshes in relation to the Gulf of Mexico often directly correlates to the level of salt content in the water. Salinity also changes based upon rainfall, drainage, soil texture, vegetation, depth of water table, and freshwater inflow.
The salinity range for each marsh type is as follows:
Freshwater – 0 ppt (parts per thousand)
Intermediate – 0-5 ppt
Brackish – 5-15 ppt
Salt – 15 or greater ppt
A wide variety of animals such as nutria, turtles, and many bird species can be spotted in the freshwater and intermediate marshes of Louisiana, as well as species of special concern like Louisiana black bears and Calcasieu painted crawfish. The exchange between freshwater and salt water is frequent in the state of Louisiana due to its close proximity to the Gulf of Mexico. An estuary is characterized by this mixture of freshwater and salt forming brackish water where many wetland species spend their juvenile lives. The estuaries of coastal Louisiana support economically important fisheries and provide important wildlife habitat. Crabs, fish, and shrimp are a few of the animals found in Louisiana’s salt marsh, and birds like brown pelicans and reddish egrets often nest in the shrubby vegetation bordering salt marshes. Each of these marsh types play a significant role. It is vital to keep these marshes healthy for them to maintain their value and support the people, plants, and animals of Louisiana.
Animal diversity in the wetland biome is greater than in any other biome type.
Wetland biomes are the perfect place for a variety of plants and animals to thrive due to the climate, food availability, and shelter provided. Amphibians and reptiles do particularly well in this environment. Some reptiles, such as turtles, need wetlands because they either live in water for much of their lives or largely rely on water for their survival. Wetlands support a variety of animals that provide plentiful food sources for reptiles. Snakes spend time around rivers and wetlands where there are food sources such as frogs and bird eggs.
Other species that populate the wetland biome are birds. Wetlands are an important habitat for birds that are breeding, nesting, and rearing young, and some bird species, stop to feed in wetlands along their migration route. The value of a wetland to a specific bird species is dependent upon the presence of surface water and the duration and timing of flooding, for example great egrets may nest in trees above water for protection from predators. The geographic location of a wetland also determines how and when birds will use it.
Alligators and crocodiles are the largest animals found in the wetland biome. The type of water found will strongly affect the types of life that survive there. When salt is present in the water, you might find shrimp and shellfish which are some of the smallest wetland animals.
Crawfish in defensive posture with claws extended, “Secret Bird Pond”, Trinity River Audubon Center, Dallas, Texas, USA.
National American Eagle Day is observed each year on June 20th. This day is celebrated in honor of our national symbol, to raise awareness for protecting the bald eagle, to assist in the recovery of their habitat, and to educate Americans on their significance. The bald eagle can be sighted during its breeding season at nearly any wetland habitat such as seacoasts, rivers, large lakes, or marshes. You can find these eagles around large bodies of open water with an abundance of fish.
In the mid 20th century, America’s precious eagles were almost lost due to the effects of habitat destruction, poaching, and environmental negligence, specifically the contamination of food sources by the pesticide DDT. Thanks to conservation efforts of various organizations, conservationists, and protection laws – the bald eagle populations recovered. Habitats restored through CWPPRA projects aided in the delisting of our national symbol from the endangered species list in 2007. CWPPRA has protected, created, or restored approximately 97,177 acres of Louisiana’s vanishing coastal wetlands in its first 25 years. Those restored swamps, marshes, barrier islands/headlands, and associated open-water habitats provide foraging, nesting, breeding, wintering, escape cover, and nursery habitat for wildlife, in particular the American bald eagle.
On May 23, we celebrated the 17th annual World Turtle Day sponsored by American Tortoise Rescue. This nonprofit organization was established in 1990 to protect all species of tortoises and turtles. They created World Turtle Day to serve as an annual observance of protecting tortoises and turtles around the world and their disappearing habitats. Wetlands that serve as habitat for turtles include shallow fresh waters, pelagic salt waters, and heavily and scarcely vegetated areas. Various species of turtles reside in every type of wetland environment.
Did You Know?
The majority of turtles that you see on the road are females traveling to their annual nesting sites.
Turtles like to eat dead material lying on the bottom of ponds, lakes, and wetlands. Turtles keep the water clean!
Snapping turtles rarely snap at humans in water. They do not like the way people smell or taste.
If you are helping a turtle cross the road, be sure to move the turtle in the same direction it was originally headed. DO NOT turn it back around! It is likely it will try to cross the road again.
If you touch a turtle, it is important that you wash your hands thoroughly. Turtles may carry salmonella.
How to Protect Turtles?
Avoid walking or driving on sandy areas where turtles are nesting.
Create a “no wake zone” to reduce damage to shoreline wetland habitats and stop the removal of plant materials.
Do not remove turtles from their natural habitats.
What Can You Do?
You can put signs and small barriers around nesting sites and wetlands that are on your property.
You can contact local programs to help pay for habitat restoration in your area.
You can add beneficial features to turtle habitat by planting native plants to buffer wetlands and turtle nesting areas. This will attract frogs, snails, insects, and other species that turtles eat.
World Migratory Bird Day was initiated over ten years ago as a way to raise global awareness for the conservation of migratory birds and their habitats. Each year, people around the world organize events, such as bird festivals, exhibitions, and bird-watching excursions to celebrate this day. All activities celebrating World Migratory Bird Day are tied together by a common theme. World Migratory Bird Day 2017 was officially celebrated on Saturday, May 13 with the theme “Their Future is Our Future,” which shed light on the interdependence between people, nature, and migratory animals — particularly birds. The goal of this year’s campaign is to raise awareness of the need for sustainable management of natural resources, including wetlands, demonstrating that bird conservation is crucial for the future of humanity.
Among the wetland attributes society aims to protect and restore are those that benefit wildlife, such as migratory birds. One of the best known functions of wetlands is to provide a habitat for birds to breed, nest, and rear their young. This natural resource is used for drinking water, feeding, shelter, and social interactions. Wetland vegetation provides protection for migratory birds from predators and destructive weather. The presence of an adequate shelter is often crucial to the survival of migratory birds.
The value of a wetland varies for each bird species depending on the amount of surface water, amount of moist soils present, and the duration of flooding. Other factors that commonly affect the value of wetlands to a specific bird species are availability of food and shelter and the presence or absence of predators within the wetland. Availability of water influences whether migratory birds will be present, how the birds will interact with the wetland, and which species will be present. Species of migratory birds may spend the winter months in the Southern United States using the wetlands for food and nutrients to sustain them for their journey north. Many migratory birds are highly dependent on wetlands during the migration and breeding seasons. Habitat loss in breeding areas means population loss for most wetland dependent birds.
The goal of building terraces is to achieve some of the same objectives as full marsh creation but over a larger area of open water, where marsh creation alone is not feasible. Terraces are long, earthen berms that are built by mechanically dredging material and piling and shaping the material to a desired height. Most terraces average around 3 feet tall, with shallow side slopes and a wide base. This size and shape optimize the amount of terrace that falls in the intertidal zone and will support wetland vegetation.
The objectives of constructing terraces are several and depend upon the location in which they are built. These include acting as a sediment trap to help build new land, reducing wave fetch and erosion on adjacent marsh shorelines, creating habitat for fish and waterfowl, and improving water quality to promote the growth of aquatic vegetation. Terracing projects constructed under CWPPRA have achieved each of these goals, with sediment trapping being most evident near the openings of sediment-laden bays or navigational waterways.
Terracing has become a widely used technique that is expanding across the Gulf Coast because of the success and cost-effectiveness demonstrated through CWPPRA and privately funded projects. Although these features may not look like natural marsh and often use geometric configurations, they are able to perform a lot of the functions of natural marsh in areas that have become vast open water. Developing this cost-effective technique for use in areas that have few other restoration options is a testament to CWPPRA’s ability to adapt to funding constraints and a quickly changing environment.