Why Worry About Wetlands?

Objectives:

1. To develop an awareness of the functions and values of wetlands.
2. To understand the relationship between healthy wetlands and the quality of life in the Lake Pontchartrain Basin.
3. To demonstrate understanding of the cause-and-effect relationship between wetland loss and other environmental issues in the Lake Pontchartrain Basin.

Multiple Intelligences Learning Activities:

Verbal/Linguistic:

Write captions for a calendar on the biodiversity of the Lake Pontchartrain Basin. Write summaries of newspaper articles and reflective journal entries on weekly events that occur in the Basin.

Logical/Mathematical:

Graph results of "feeding" niches of wetland birds. Evaluate a local wetland for its ecological health.

Visual/Spatial:

Design a calendar of exotic, introduced, endangered, and threatened species in the Lake Pontchartrain Basin. Develop a chart illustrating causes and effects of wetland loss in the Lake Pontchartrain Basin.

Bodily/Kinesthetic & Musical/Rhythmic:

Compete for food in "Bird Beak Buffet". Evaluate a wetland site for relative functions and values.

Interpersonal:

Work cooperatively to develop a consensus on the ecological health of a wetland site in the Lake Pontchartrain Basin.

Intrapersonal:

Interview family, friends, and peers on present observations and past changes witnessed in the Lake Pontchartrain Basin.

Wetland Habitats

Click the map for a larger view.

The Lake Pontchartrain watershed is extensive and comprises many diverse habitats. Water moves across fields and through forests as it finds its way to small stream in the forested hills north of the lake. This same water joins large rivers and bayous as it journeys downward to the sea. One common factor uniting the entire watershed is that all of its water eventually arrives in a wetland for final filtering and purification before it empties into the Gulf of Mexico.

Wetlands surrounding the Lake Pontchartrain Basin are quite diverse. They range from freshwater, river forests (riparian wetlands) in the northern part of the Basin, through cypress/tupelo swamps in the western and middle portions of the Basin, to fresh, intermediate, and finally brackish and salt marshes in the extreme eastern end. While it is easy to tell the differences between swamps and marshes because marshes have no trees, the difference between swamp and river forests and among various marsh types are more difficult to determine. Distinctions are usually determined by the dominant vegetation types.

River forests are made up of mostly trees like bald cypress and tupelo gum, certain types of oak, magnolia, beech, but also include some scrubby shrubs like palmetto and wax myrtle. These river forests usually drain into some other type of wetland such as cypress/tupelo swamps or fresh marsh before emptying into Lake Maurepas or Lake Pontchartrain. Cypress/tupelo swamps, as you might have guessed, are comprised almost exclusively of cypress and tupelo gum trees, but also contain some understory shrubs like button bush and wax myrtle, along with many aquatic plants like water hyacinths and duckweed as well as semi-aquatic plants like spider lilies, swamp lilies, and irises. Marshes generally have little or no trees, but each marsh type has its own particular vegetation types, such as Spartina alterniflora, Spartina patens, or Sagittaria lancifolia.

Just as each wetland type is characterized by different kinds of vegetation, each wetland type is also home to particular kinds of animals and plants adapted to living in these special habitats. Some of them are being outcompeted for resources of food, sunlight, space, and shelter by exotic or introduced species. Others have become endangered or threatened due to habitat destruction or water pollution. Following is an activity that will focus student attention on this issue:

Activity: Countdown Calendar

"I'm seeing and doing things I never thought I'd ever do. Field work is exposing me to animals, plants, and places that, by studying them, are helping me to better understand the environment and what I can do to preserve it for future generations." Doug Dalier Project F.U.R. team member

Wetlands

Wetlands have often been described in the past as dreary, disease-ridden, insect-infested worthless chunks of "land". They weren't considered fit for anything unless one could drain them in an attempt to create more "usable" land. It may surprise you to know that some people still hold this idea today. Fortunately for us all, these kinds of thoughts are rapidly being replaced by factual knowledge concerning the true functions and purposes of a wetland.

Among the many functions attributed to wetland ecosystems are flood control, water purification, storm buffers, wildlife habitat, nursery grounds for larval fish and shellfish, and recreational areas.

These qualities alone provide sufficient reason for us to devote much time and energy to the restoration and preservation of wetland ecosystems. Perhaps as important is the need to inform others of the many roles wetlands play in our daily lives and to stress the need for understanding the delicate balance of these, ecosystems as well as how seemingly unrelated events can dramatically alter the health of our wetlands.

While wetlands constitute only a small percentage of the total land area in the lower 48 states, 40-45% of those wetlands are in Louisiana.

In 1990 there were 3.3 million acres of coastal wetlands in Louisiana, with approximately 483,400 acres in the Lake Pontchartrain Basin.

The functions and values of wetlands
are of paramount importance to us all and
their contribution to society is enormous.
Let's take a closer look:

Click the illustration for a larger view.

Wetland Functions & Values in Louisiana*

( the following sections is based on Wetland Functions & Values in Louisiana. Pub. 2519, LA Cooperative Extension Service. 9/94)

Commercial Values:

Commercial fishing has a direct dockside value of almost $4 billion in the U.S. More than 70% of that value consists of species that spend part of their life cycle in coastal wetland estuaries. Louisiana's coastal wetlands serve as a valuable nursery area for shrimp, oysters, menhaden ("pogey"), blue crabs,and many finfish species. This harvest is a vital part of Louisiana's economy, providing millions of dollars and thousands of jobs each year.

Alligators, once endangered in many parts of their local range, are a success story to proper wildlife management. More than 25,000 wild alligators are taken from Louisiana's wetlands each year for their hides and meat.

Furbearing animals such as nutria, mink, raccoon, otter, muskrat, bobcat, and beaver are found in great abundance in Louisiana's wetlands. About 40% of the nation's wild fur harvest comes from here. A strong fur market is a logical, valuable solution to the problem of nutria "eat-outs" in marshes of the Lake Pontchartrain Basin and the resultant wetland loss. It would provide an effective means of producing income for trappers while reducing the extensive damage to wetland vegetation caused by these members of the rodent family.

Oil and natural gas production are vitally linked to Louisiana's wetlands, providing jobs for residents and revenue for government services. This has a total value exceeding $550 million annually. Important products, like sand and gravel, are also mined from coastal wetlands. An important question for the future will be how to continue to reap the benefits of these industries while reducing damage to the environment.

Forestry is another important value of wetland areas. Forested wetlands make up more than 82 million acres of forests in the U.S. Timber production in southern wetland forests has an annual value of over $10 billion. Properly managed, this vital resource will continue to provide both income and jobs for the future. If not managed, the resource can be lost. Beautiful old-growth cypress swamps once existed in the LaBranche Wetlands and in the Manchac Wildlife Management Area, but those regions were heavily logged, and their extensive cypress forests are gone.

Recreational Values:

More than 330,000 hunting licenses and 900,000 fishing licenses are sold every year in Louisiana to sportsmen and women. Those hobbies are closely related to wetlands-dependent species of ducks, geese, and fish, but their economic value exceeds the cost of buying a license alone. Purchases such as gasoline, bait, tackle, ammunition, food, boat launch fees, hunting leases, and other items result in a combined commercial value of over $1 billion.

The swamps, bayous, and marshes of Louisiana represent a cultural value as the home of many Louisiana residents who have a strong dependence on the wetlands for their food and livelihood. This culture is unique to Louisiana and is intertwined with other recreational and commercial values of the wetlands.

Cultural Values:

People enjoy wetlands for a variety of reasons, and Louisiana's wetlands constitute a world-renowned ecological resource attraction. Some of the activities that bring visitors to our wetlands are boating, swimming, camping, water-skiing, hiking, birding, photography, journaling, and painting.

Wildlife Habitat:

Wetlands produce enormous amounts of organic material and detritus, which is directly linked with wildlife and fisheries productivity. This makes wetlands two to three times more productive than very fertile agricultural land. The abundant vegetation found in wetland areas supplies food and shelter to the many organisms found in that ecosystem.

Wetlands are known for their incredible biodiversity. Hundreds of non-game mammals, fish, birds, reptiles and amphibians, as well as over 50 wild game and fish species, inhabit wetland areas. Currently though, 79 species of animals and plants found in U.S. wetlands are on the threatened or endangered species list due to wetland loss. Over 100 other species are nearing that distinction. In the Lake Pontchartrain Basin, the Louisiana Black Bear has almost disappeared from its range, while the American alligator and the brown pelican have made dramatic comebacks.

Water Quality:

One of the most valuable functions of wetlands is their ability to filter sediments, nutrients, and chemical pollutants from the water which flows from land. Wetland plants are able to remove nitrogen and phosphorus from runoff water, especially near agricultural areas. Other wetland plants help remove heavy metals, sewage, and pesticides, thus preventing them from doing further damage in the ecosystem. These pollutants are also removed in healthy wetlands through chemical processes that occur in water and soil.

Wetlands act both as a sink and as a conduit for water. Percolation of water through soil recharges aquifers which are important sources of drinking water and industrial uses in some communities. Fresh water that flows from wetlands helps support plant and animal life during droughts and can help reduce effects of saltwater intrusion.

Storm Buffer Zone:

When tropical storms or hurricanes batter the shoreline along the Gulf of Mexico, coastal wetlands absorb the force of the wind and waves, thus protecting homes and property from excessive damage. Wetlands also hold large quantities of water that would otherwise flood residential or agricultural areas. This important function of wetlands is valued at billions of dollars.

Erosion and Flood Control:

Vegetated wetlands provide protection against erosion along banks and shorelines of bodies of water. Natural wetland loss and development contribute to shoreline erosion problems, which exceed 100 feet per year in some areas. Wetlands restoration projects are helping to slow that process, but they are costly and time-consuming. If 15% of a watershed consists of wetlands, flooding peaks can be reduced by approximately 60%. That's because wetlands, as a natural sink, hold flood waters or slow them down.

Draining and filling natural backwater areas often causes increased flood problems for nearby developed areas. In the U.S., annual losses due to flood damage amount to more than $3 billion in property damage and almost 200 human lives.

Education and Research:

Whether as an outdoor classroom for school children or as a field study site for scientific research, wetlands are unparalleled for their educational value. They are ideal places for students of any age to explore the interrelationships among various factors in an ecosystem, as well as to understand the ecological, economic, social, and legal complexities of an important environmental issue.

Activities: Countdown Calendar Lake Log: A Diary of the Basin How Healthy is this Wetland Where Have All the Wetlands Gone? Bird Beak Buffet

©1998 Lake Pontchartrain Basin Foundation

Lessons on the Lake is published by the
Lake Pontchartrain Basin Foundation
Metairie, LA