Investigating Two River Mouth Habitats
by
Robin Rutherford
W.B. Goodwin Elementary
March 15, 1999
Lesson Title:
The Best Home for Me
Subject:
Habitats
Grade levels:
fourth and fifth
State Standards:
Living Things, Strand 2C-How plants and animals interact in their
habitats with living and nonliving things
Earth and Space Systems, Strand 3B: Change-Predict changes in
landscapes as a result of erosion and deposition.
Earth and Space Systems, Strand 1A- Major surface features
Objective:
Students will investigate the habitats of two river mouths. One of
the river mouths is the Mississippi River Delta. The other is the
marsh at the mouth of a local river, the Ashley. They will be
comparing several kinds of wildlife in each environment. They
will try to draw a conclusion about the effects of erosion on the
wildlife.
Materials:
Large class-size Venn Diagram, internet-ready computer
Activity:
As a class, find out the silt content of both rivers. Students then
use encyclopedias, the internet and local resources to research
each habitat . The students complete a large Venn
diagram about the wildlife of the Ashley river marsh and the
Mississippi River Delta. Then individually, students choose two
animals from each habitat to research, looking for clues to why
animals chose the habitat that they did. They should be especially
watchful for any clues that might have to do with levels of
silt (minerals) in the water.
Evaluation:
We will be using a rubric that has the following criteria:
4-Students need to be able to give a logical reason why their
wildlife live in the habitat that they do. They will have research
about each habitat and 2 animals in each
environment They will contribute to a class venn diagram.
3-Research habitat and animals, have venn diagram or a logical
reason why an animal lives in their habitat.
2-Research habitats and animals.
1-Research only animals or habitats
0-anything less than 1
Extensions:
Obtain a jar of Mississippi River delta water. Obtain a jar of Ashley River
water. Let the jars sit for a few days to allow to sediments to settle.
Measure or weigh the amount of sediment left in each jar.
Make stream table models of the way the Mississippi River flows and the
way the Ashley River flows. Research what erosion can do.
Build a model of a delta or a river system with a marsh.
Integrated
Concepts:
Social Studies-Relate the topic to a comparison of the pre-civil war cities
of New Orleans and Charleston.
Bibliography
Fish and Wildlife Service
http://www.fws.gov/r4slr
Microsoft Encarta Virtual Globe
Old Man River Web Page http://www.oldmanriver.com/name.htm
Sea Science, Dynamics of the Salt Marsh-Department of Natural Resources
http://www.dnr.state.sc.us/marine/pub/seascience/dynamic.html
World Book Encyclopedia 1990
Marsh Animals
Delta Animals
catfish
fiddler crabs
snails
mussels
oyster
Clapper Rail
red-wing blackbird
diamondback terrapin
loggerhead sea turtle
pelican
heron
egret
duck
alligator
osprey
plover
eagle
flounder
blue crab
shrimp
peregrine falcon
swamp rabbits
speckled trout
redfish
buffalo fish
nutria
Habitats
DELTA: This is a piece of land usually shaped like a triangle. It is caused by the build-up of
sand or mud at the mouth of a river. The size of the delta depends on the strength of the
river. A swiftly flowing river carries sand off to form barrier islands or sandbars. Slowly
flowing currents at the mouth of the river will form a delta. The delta of the Mississippi River
covers about 35,000 square miles. The land in this delta is fertile land, that is mineral rich. It
yields valuable crops of high grade cotton. Forty percent of North America’s duck geese,
swan and wading bird species rely on the river and delta as migration flyway and resting
place. The Mississippi River delta supports a wide variety of wildlife, including wintering
waterfowl, which take advantage of the rich food resources found in the delta. The marsh
and waterway provides a year-round habitat for a diversity of fish and shellfish species.
Speckled trout, redfish, flounder, blue crabs and shrimp are some of the most populous
species. Shorebirds such as yellowlegs, dowithchers, dunlins and western sandpipers use
the delta as a resting place during migration. There are several kinds of fur-bearing species
that live on the delta. They include deer, swamp rabbits and nutria. The nutria is the most
abundant of these. The Mississippi is the home to several endangered species as well.
These include American alligator, brown pelican, Arctic peregrine falcon and piping plover.
Marsh in a River System: Marshes are transitional areas between land and water
where salt water from the ocean and fresh water from the river mix together. Salinity,
frequency and extent of flooding determine the types of plants and animals found there. The
most abundant plant is the spartina grass or cordgrass. Many animals live on this plant like
the periwinkle snail. . When spartina dies and sinks to the bottom of the marsh it becomes a
food for many animals. Animals such as worms, fishes, shrimp and blue crabs feed on the
decaying plant matter in the bottom of the marsh. Fiddler crabs, marsh snails and marsh
mussels are some of the invertebrate species found there. Oysters generally grow on the
borders of the salt marsh. There are many insects there who feed on plants. And in turn,
many birds depend on them for food. The red-winged blackbird is one of the inhabitants of
the marsh that depend on insects for food. Blue herons and snowy egrets feed on fishes
shrimp and fiddler crabs. Sediments in the marsh play an important part in determining plant
and animal communities. There is usually an organic layer over a clay silt layer. The organic
layer is primarily dead plants. This often contributes to the marsh smell.
Animal Research
Buffalo Fish
There two delta animals which I have researched. The first is a buffalo fish. It is a large
dark-colored fish that usually lives in fresh water. They can inhabit rivers and lakes all over
North America. It can grow to be as long as three feet and as heavy as fifty pounds. They
are similar to carp but have no whiskers. They have a slightly humped back and are often
called big mouth buffalos. They feed mainly on zooplankton.
Nutria
This animal is a large rodent that lives near water. They have brown fur with a white nose,
small ears, webbed hind feet and a long bare tail. Their total body size including the tail can
measure up to 40 inches. They can weigh up to 20 pounds. They are originally from South
America but were introduced in North America for their fur. However most attempts were not
successful. Nutrias live along the banks of rivers, marshes and ponds. They are great
swimmers and feed on water plants. They can be serious pests due to the fact that they
often dig holes in dams and dikes. Nutrias are trapped in Louisiana where their fur is made
into coats and gloves.
Brown Pelican
The brown pelican is a large water bird with a long straight bill. It has a flexible pouch made
of skin on the under side of its beak. They use this pouch to catch fish, their primary food.
They are very strong swimmers and have webbed feet. The brown pelican is found as far
north as North Carolina and British Columbia. It measures about four feet long with a wing
span of about seven feet. Brown pelicans catch fish by flying above the water until it spots a
fish and then diving for it. Pelicans nest in large groups called colonies. Twigs and plants
are what they use to construct a nest. Pelicans can lay up to three eggs which hatch within a
month.
Catfish
Catfish are really a large group of fish that have whiskers, also called barbels. These barbels
resemble the whiskers of a cat. Catfish do not have scales. Although several kinds have
sharp spines. There are almost 2000 species of catfish, with most inhabiting fresh water.
However, some do live in salt water. Catfish eat almost any kind of marine organism,
including frogs, insects and other fish. In some species of ocean catfish the males incubates
the eggs in his mouth and doesn’t consume any food until they hatch. The catfish has gills
and other air breathing organs as well. There are about 45 species of catfish native to North
America. Some kinds include flatheads, channel and bullhead catfish.