Volume 23 - April 26, 2004
A large patch of water hyacinths, the devil in disguise, will choke off the rest of this bayou in two weeks.


Four exotic species in one photograph can totally clog up and change a habitat for the worst. Pictured: water hyacinth, alligator weed, elephant ear, and tallow trees.

The United States is filled with plant and animal species that do not naturally occur here. Camellias are beautiful flowers that many people in Louisiana grow and enjoy. These non-native or exotic plants cause no harm to the natural ecosystem. Some exotic species that are introduced into a habitat become invaders. An exotic invasive species is bad news to any habitat!


Louisiana has some foreign invaders that are changing wetland ecosystems and upsetting the natural balance in many areas. CC and I are seeing this everyday as springtime is a growing time for many of the marsh invaders. An ecosystem is a fragile thing and if something enters a system that can eat, destroy, or crowd out the native species you have big problems.


Some of the invasive species we are seeing on marshmission are nutria, water hyacinths, hydrilla, salvinia, Chinese tallow trees, and zebra mussels. These invaders were introduced to Louisiana in many different ways and they are causing many different types of damage.

Let’s look at some of the problem invaders of our wetlands.




WATER HYACINTH: CC calls this invading plant “Devil in Disguise.” It is a lovely flowering water plant that was introduced in Louisiana in the 1884 World Industrial Cotton Exposition in New Orleans. Visitors to the Japanese exhibit were given a hyacinth as a gift. Many “gifts” were put in local ponds and waterways and quickly spread. Quickly is the key word as these plants can double their population in 2 weeks clogging up bayous and waterways. Many times CC and I have had to walk our canoe over huge floating patches of water hyacinth. The thick patches also cut off the sunlight to the plants and animals below the water’s surface killing them. The beauty of the water hyacinth really is a disguise!


NUTRIA: Annie wrote about the “naughty nutria” in volume 7 of the Coastal Classroom.    Archive back to Annie’s column and read about this invader of the marsh!


SALVINIA: This tiny water fern floats. You may have bought some to decorate your fish aquarium or outdoor pond. When released, this plant reproduces rapidly and clogs canals and bayous. Salvinia also takes over native species such as duck weed which is a very important food source for many water birds.


HYDRILLA: Another invasive water plant used in aquariums that grows thickly under water. It takes over waterways and can really ruin the motor of your boat.


CHINESE TALLOW TREES: This ornamental tree came to the United States from China in 1776 by Ben Franklin. The seed of this tree was used to make wax for candles and soap. Tallows were planted in the Gulf States to start a soap industry. Today people plant them because they are pretty. In the wild, this tree easily adapts to different habitats and takes over as the dominant plant. When mature this tree produces 100,000 seeds per year!


ZEBRA MUSSELS: This tiny invader is a freshwater bivalve that came to the U.S. in water discharged from large ships. It is native to the Soviet Union and has spread through the country. The waters of the Mississippi have carried this mussel to our region and it is a real nuisance. It competes with our native mussels and wins! Zebra mussels also ruins water filtration systems and water intake pipes by attaching to them.


Lots of time and money is spent to stop the spread of these and other invading species. Once a truly invasive species is introduced it is almost impossible to control. Be careful with what you release into lakes or ponds, you never know what can become an invader!  

Beary Sweet!

Baby black bear attempting to climb tree.

“Lions and Tigers and Bears, OH MY!”  I have met Mike the Tiger at LSU and I have seen lions at the zoo, but these two creatures are non-native species to Louisiana. Bears, on the other hand, are native to Louisiana!


The Louisiana Black Bear is a different type (subspecies) from the black bears in other states. Louisiana Black Bears, Ursus americanus luteolus, are a threatened species. The population of these special bears dropped a lot in the last century. With the help of biologist they are coming back to south Louisiana, particularly in the Atchafalaya Basin, Vermillion, Iberia, and St. Mary Parishes. It is strange to think of bears in the marsh, but Robert Helm, a duck biologist, saw one lying on top of a muskrat mound as he flew over the marsh on a duck survey! CC says that we need to conserve bears and their habitat, so that they will continue in Louisiana.


Adult male bears can weigh from 250 to 400 pounds and adult females range from 120 to 275 pounds. Females that are mature can have from 1 to 4 cubs every other year. The mother cares for the young for a year or so. Bears sleep in a den in the winter. In Louisiana males rest in temporary dens and may get up to move and eat. Females stay in the den from December until May. 


Bears are large mammals and need lots of habitat to live. Wooded areas are their favorite as they are excellent tree climbers. Trees provide shelter, safety, and food for them.  Bears are classified as carnivores, but these shy creatures eat anything available. Nuts, berries, and small animals are their usual fare. Problems arise when bears find human garbage or crops because they are opportunistic feeders and eat anything they can find. Almost all trouble between humans and bears occur as a result of the bear’s search for food. Bears have a super sense of smell (just like a dog) and can find food when it is left around. Never feed a bear because if a bear loses his instinctive fear of humans he will become a real nuisance and that could be bad news for the bear!


Bears are smart, secretive, and timid creatures. I sure hope that we leave them enough good bear habitat so that they can make a strong come back in LOUISIANA!

- Since the introduction of exotic invader plants and animals can be both deliberate and unintended, it is bound to happen sooner or later. Usually effective control of new invader plants and animals is extremely expensive and almost impossible to achieve.
- For every acre of wetlands that is drained for housing subdivisions or farm fields there is one less for wildlife natural habitat. We need to start leaving room for our native wildlife species to thrive!
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1. Visiting a zoo or botanical garden is always, of course, a fascinating experience. It helps us to understand why exotic plants and animals were deliberately brought to our country. Problems arise when to everyone's surprise the introduced species become a nuisance. Write a paragraph about the animals or plants you saw at a zoo or botanical garden that excited you the most.

2.Check out this weeks activity in the Lagniappe Section of Marshmission. It is a yummy recipe for Bear Biscuits!

Also visit You can order OH NO! HANNA'S SWAMP IS CHANGING, a book by Marilyn Barrett-O'Leary. It is one of our suggested children's books on invasive species. It really is a cool book!

See more of CC's images of cute black bear cubs.
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la·gniappe    (ln-yp, lnyp)
2. An extra or unexpected gift or benefit

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L.J. Alleman Middle School asks:
When you ride in your houseboat, do you sometimes run over stuff like alligators, snakes, or floating logs?
CC answers:  We dodge floating logs and patches of floating vegetation.  Alligators and snakes dodge us.
L.J. Alleman Middle School asks:
What have you liked the most on your trip in the marshes so far?
CC answers:  The beautiful spring with eagles and flowers everywhere.
L.J. Alleman Middle School asks:
What do you miss the most?
CC answers:  Sue misses her bathtub and recently the air conditioner because it is starting to get hot.  I miss nothing and could live out here forever.
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