Download Succession

Succession
Summary:
Grade Level: 5-7
Teaching Methods: Analysis, Classification,
Data Collection, Discussion, Investigation,
Observation, Small Group
Time:
• Preparation Time: 1 hour
• Activity Time: 2 hours
Materials:
Activity I
• Stake wire flags
• Flagging tape
• Flip chart
• Markers—at least two different colors
Per Group
• Soil thermometer
• Air thermometer
• Light meter
• Anemometer
• Trowel
• Ruler
• Beginner field guides or make a
common plants and animals handout
(see Getting Ready)
• Community Claims worksheet
• Clip boards
• Pencils
Activity II
• Stages of Succession worksheet
• Clipboards
• Pencils
Park Location:
Activity I—An area where two different
stages of succession meet and show a
gradual change from one community to
another.
Activity II—An area with different
successional stages other than those in
Activity I.
Pre/Post Lessons:
• Pre-visit: Mapping Communities
• Post-visit: Signs of Succession
Students investigate different stages of succession to identify their characteristics and learn that one community gradually replaces another.
Objectives:
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Students will identify at least two characteristics of different successional communities.
Students will describe the features of an area where two communities meet and overlap.
Students will define the term succession.
Students will recognize six different ecological zones of succession found on Presque Isle.
PA Environment & Ecology Standards:
4.6.7. Ecosystems and their Interactions
A. Explain the flows of energy and matter from organism to organism within an ecosystem.
C. Explain how ecosystems change over time.
4.7.7. Threatened, Endangered and Extinct Species
A. Describe diversity of plants and animals in ecosystems.
B. Explain how species of living organisms adapt to their
environment.
PA Science & Technology Standards:
3.2.7. Inquiry and Design
B. Apply process knowledge to make and interpret observations.
3.3.7. Biological Sciences
A. Describe the similarities and differences that characterize diverse living things.
3.7.7. Technological Devices
B. Use appropriate instruments and apparatus to study materials.
Other PA Standards:
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Geography
Mathematics
Reading, Writing, Speaking and Listening
Background:
With the passage of time, natural communities change. Old fields become
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forests and ponds become marshes. The orderly replacement of one natural community by another is called succession. This process is brought about, in part, by the organisms themselves. Their own life activities create habitats that are more favorable for different groups of organisms.
Primary succession takes place if the site contains no
plants or soil, such as a sandy beach. In primary succession on land, living organisms slowly build soil over hundreds of years. Secondary succession occurs in areas
where soil and organisms were already present, but were
disturbed by natural or human activities.
The early stages of succession are characterized by relatively few species, low biomass, and an abiotic source of
nutrients. Plants at this stage have shorter, simpler life
cycles, are smaller in size, and generally produce an abundance of small seeds that can be widely dispersed. These
plants are adapted to a wide range of conditions and grow
rapidly.
Plants of later stages are slower growing and long-lived,
support more biomass, and produce smaller numbers of
heavy seeds that are primarily dispersed by animals or
gravity. The final stage of succession is called the climax
community. This stage is mature, self-maintaining, and
relatively permanent as long as it is left undisturbed.
The change from one community to the next is gradual.
Although each stage can be recognized by its physical
structure and characteristic plant and animal species, there
is no clear line between one stage and another. The zone
where two or more different communities meet and mix
is called an ecotone. These transitional areas contain species of both communities and often exhibit the greatest
variety and density of life. This phenomenon is known as
the edge effect. Some species also have changing habitat
needs throughout the year and may utilize different communities and their ecotones for nesting, seasonal feeding,
or winter shelter.
Due to the action of wind and water, Presque Isle is constantly changing. Sand is carried from the northwest facing
beaches and deposited at the easternmost end at Gull
Point forming new land. The changing nature of Presque
Isle has resulted in six distinct ecological zones of succession:
• Water’s Edge, Drift Beach, and Upper Beach
• Sand Plain, New Ponds, and New Dunes
• Fore Dunes, Back Dunes, and Ridges
• Old Ponds and Marshes
• Thicket and Sub-Climax Forest
• Climax Forest.
The variety of habitats these zones provide result in a high
level of biodiversity. Presque Isle is home to over 600
species of plants, over 320 species of birds, 50 species of
mammals, 31 species of reptiles and amphibians, and thousands of invertebrates.
Zone 1: Water’s Edge, Drift Beach, and Upper
Beach
The first stage of succession at Presque Isle occurs where
Lake Erie waters meet land. Wind and wave action constantly moves sand on, off, and along the beaches making
the water’s edge a harsh and unstable environment. It
takes approximately one year before plants that are
adapted to the desert-like conditions can become established. Annual plants, species that live for only one year,
are the first to move into the area. These plants are able
to colonize the water’s edge, because they grow quickly
and produce large numbers of seeds. Plants help to stabilize the sand and add nutrients when they decompose.
Three annual plant species found in this stage are Sea
Rocket, Beach Clotbur, and Seaside Spurge. Many types of
birds eat the seeds of these plants and help to disperse
them. The water’s edge also provides habitat for migratory shorebirds, such as plovers and sanderlings, which
feed on insects and nest on the beaches.
Zone 2: Sand Plain, New Ponds, and New Dunes
Over time, sand is moved farther inland away from the
wind and waves. Once removed from the elements, the
stabilized, nutrient rich sand can support perennial plants,
which live for multiple years. Sand is trapped by the taller,
thicker vegetation and builds up at the base of the plants
to form a sand plain. Perennials that live in the sand plain
include the Hairy Puccoon, Brook Lobelia, Beach Pea,
Rose-Pink, Flax, and Cypress Spurge. These plants provide habitat for birds and small mammals.
Sand deposits curve around the eastern tip of the peninsula and enclose water to form new ponds. These ponds
are often temporary, because they can fill with sand or
wash away. However, if they do survive, plants and wildlife will eventually appear. Cottonwoods are among the
first to appear, because they are adapted to survive in
saturated soils.
Zone 3: Fore Dunes, Back Dunes, and Ridges
Sand is carried inland from the beaches until it is blocked
by vegetation. As sand continues to build-up, it forms
small dunes. Dune grasses and other vegetation begin to
grow, which traps more sand and allows the dunes to
grow bigger. As the plants die, they add nutrients and
build a richer soil that can support other types of vegetation. Eventually, the dunes will be covered with grasses
such as American Beach Grass and Switch Grass and bay-
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berry. The new vegetation provides habitat for many
types of birds, reptiles, amphibians, and mammals. Yellowrumped Warblers feed on bayberry fruit and foxes and
coyotes build dens in the dunes.
vertical layers of the trees provide additional habitats.
Zone 4: Old Ponds and Marshes
Ponds that are protected from the wind by dunes and
ridges develop into stable habitats for many plant and animal species. Old ponds and marshes have a high level of
biodiversity because they provide a variety of habitats.
Cattails, sedges, and rushes grow along the pond’s edge
while water lily and other aquatic vegetation grow in open
water. These provide food and shelter for turtles, frogs,
snakes, birds, and beavers.
Vegetation can be used as an indicator of a pond’s age.
Water lily can be found on ponds that are about 40 years
old; while Tufted Loosestrife indicates the pond is between 100 and 200 years old. As a pond ages, debris begins to collect along the edges and heavy algae covers the
surface, eventually closing the open water and depriving
the pond of light and oxygen. As the pond dies, a marsh
slowly develops. Plants, such as Blue Flag, willows, alders,
and buttonbush, provide food and shelter for wildlife. The
marsh is also habitat for many types of insects, including
dragonflies and mosquitoes, which attract birds, frogs, and
other insect-eaters.
Zone 5: Thicket and Sub-Climax Forest
Dunes, ridges, and drying marshes are eventually replaced
by thickets. Poison ivy, greenbriars, bittersweet, and wild
grapes are found in these thick, shrubby areas. Thickets
provide excellent habitat for small mammals and birds, because they provide protection from larger animals and
food in the form of berries and fruit.
Seeds from wild cherry, cottonwood, white pine, red maple, and other trees are carried to the thicket by animals
or the wind. As the seedlings begin to grow, they produce
shade which thins out the shrubby undergrowth. This
stage is known as the sub-climax forest. The border between the thicket and sub-climax forest forms an ecotone,
which provides protection from predators for wildlife that
travel between the two areas.
Zone 6: Climax Forest
Hemlocks, sugar maples, and red and black oaks make up
the climax forest. The term “climax forest” suggests that
if left undisturbed, this ecosystem will remain for many
years. The trees that are characteristic of the climax forest have large canopies that produce deep shade. Understory trees, ferns, mosses, and woodland wildflowers are
adapted to shade and thrive beneath the canopy. Climax
forests support a diverse animal population, because the
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