ecological communities within the hillsborough river...

READING Lesson 3 – A Comparison of Communities

School District of Hillsborough County 1 The Southwest Florida Water Management District

Ecological Communities Within the Hillsborough River Watershed

Essential Question: How do the ecological communities within the Hillsborough River Watershed compare to each other?

Objective: At the end of the lesson, students will be able to explain how the ecological communities within the Hillsborough River Watershed compare to each other.

Standard(s): LAFS.6.W.3.7 Conduct short research projects to answer a question, drawing on several sources and refocusing the inquiry when appropriate. LAFS.6.RI.1.1 Cite textual evidence to support analysis of what the text says explicitly as well as inferences drawn from the text. LAFS.6.RI.3.7 Integrate information presented in different media or formats (e.g., visually, quantitatively) as well as in words to develop a coherent understanding of a topic or issue. LAFS.6.W.2.4 Produce clear and coherent writing in which the development, organization, and style are appropriate to task, purpose, and audience. Materials:

• Pen or Pencil • 2 pieces of notebook paper (loose leaf) • Student page: UNRAAVEL Reading Strategy handout (A copy provided for every student ) • Student page: Ecological Community Comparison Sheet • Student pages: Ecological Community Fact Sheets - Wet Meadows & Prairies, Cypress Domes,

Mesic Pine Flatwoods and Hydric Hammock. Setup/Prep time: 10-15 minutes Lesson Duration: 50 minutes/one class period Directions: 1. Explain to the students that there are a variety of ecological communities found within the Hillsborough

River Watershed. 2. Give students a copy of the UNRAAVEL Reading Strategy Handout and explain what this is for (3 min). 3. Pass out copies of 2 of the fact sheets (listed in materials) to each student. 4. The students will use the UNRAAVEL strategy to gain understanding and make connections with the

reading material they are reviewing. 5. After students have read both of their assigned readings, they will use the ecological community

comparison chart to compare and contrast their two ecological communities. (35 min)

Assessment: Students will create a learning log for each ecological community studied. They will provide examples and main points in the articles. (10 min) Alternative Strategies: • Main Idea-Detail Notes (Two Column) • Concept Map



UNRAAVEL Reading Strategy

U nderline the title

N ow predict the passage

R un through and number the paragraphs

A re the questions being read

A re the important words circled

V enture through the passage

E liminate

L et the questions be answered, and write the paragraph # where you found the answers.



ECOLOGICAL COMMUNITY COMPARISON SHEET

COMMUNITY COMMUNITY

Similarities Differences

Summary



MesicPineFlatwoods

Historically, pine flatwoods make up the most abu

ndant plant community in the Hillsborough River Watershed. However, this system is the most heavily altered by human action. The pine flatwoods system depends on frequent fires to maintain its existence. As development has occurred in the Hillsborough River watershed, wild fires have been greatly reduced. Large areas of pine flatwoods have also been harvested for both their sap and their lumber.

In the past, pine flatwoods within the watershed were dominated by longleaf pines. These trees grew tall and their branches spread wide from the trunks, controlling the amount of sunlight reaching the ground. As a result,

the understory was covered by pine needles and only consisted of a few plant species. Among these were a few saw palmettos. When the original longleaf pines were cut, the palmettos spread. The pine flatwoods we see today have much less open space than the original forest.

During the wet season, water frequently stands on the hardpan's surface and may briefly flood much of the flatwoods. During the dry season, there is very little water available to plants whose roots cannot grow through the hardpan. This creates stressful conditions for plants both in the wet and in the dry season.

Both longleaf pine and saw palmetto need fire to survive. Historically, lightening started these fires. As a result, this ecosystem often burned in the summer where the thunderstorms brought both the source of the fire and the water to put it out.

Photo by Dr. David LaHart

Most of the natural fires burned along the ground. This process recycled the nutrients locked in dead pine needles and palmetto leaves. Fire controlled the spread of hardwood trees such as oaks into the environment occupied by this ecosystem.

MesicPineFlatwoods (Cont.)

This process of burning was continued by Native Americans who set fires in the pinewoods to create more habitat for deer. This also helped the growth of the coontee plant that was used for food.

Mesic pine flatwoods occur on relatively flat land that may drain poorly during the rainy season. The soil usually consists of one to three feet of acidic sand covering a hardpan or clay subsoil. This subsoil reduces the percolation of

sawpalmetto

understory



water. As a result, during the rainy season, this system may be covered by several inches of water.

When the longleaf pines were harvested, slash pines were often planted in their place. These trees grow faster than longleaf and were often planted in rows to make cutting easier.

The slash pine produces smaller cones and shorter needles than the

longleaf pine. It also has a smaller crown which blocks less sunlight. This provides more opportunity for the expansion of saw palmetto and other sun loving species.

These alterations by human activity have changed the nature of the pine flatwoods system. Today in most parts of the watershed, this system is largely made up of slash pine and palmetto. Only a few remnants of forest similar to the original longleaf flatwoods still remain.

The mesic pine flatwoods provide essential forested habitat for a variety of wildlife species. Historically, wide-ranging, large carnivores such as the Florida panther and the Florida black bear occurred in this ecosystem. Mid-sized animals such as bobcats and foxes were also common. Other mammals included fox squirrels and deer.

Mesic flatwoods provide nesting areas for tree-cavity dependent and tree-nesting birds. They also offer food and cover for ground-

nesting birds such as bob-white quail. They serve as resting areas for migrant birds.

gopher tortoise

Mesic pinewoods are rich in reptiles including gopher tortoises, box turtles, eastern diamondback rattlesnake, and black racers. They

are also home to a variety of toads and frogs.

On some public lands within the Hillsborough River watershed, land managers are restoring longleaf pine flatwoods. This is being done to increase the biodiversity and therefore the health of the natural systems. This effort will take many years as longleaf pines may take sixty or seventy years to reach maturity.

Source:USFWS



THE HYDRIC HAMMOCK

The hydric hammock is found in a moist area which may flood during the

summer rainy season. It houses a mixture of broadleaf evergreen and deciduous trees such as laurel oaks and maples. The deciduous trees shed their leaves every winter during the middle of the dry season. The laurel oaks play an especially important role as they develop a fungal infection called "black heart disease". The fungus attacks the tissue on the inside of the trunk and limbs. As a result, as the tree ages, it develops a variety of cavities and hollow areas which house insects that feed on the decaying tissue.

These decaying areas are attacked by woodpeckers and other animals which feed on the insects. As a result, the laurel oak, as it ages, becomes a major habitat for many types of animals who live in holes and hollows.

Other trees which may be found in the hydric hammock are sabal or cabbage palm, sweet bay and sweet gum. Beautiful flowers like the

purple violet and the white violet grow wild in the ha

mmock.

Sabal palm

THEHYDRICHAMMOCK(cont.)

Numerous fern varieties such as resurrection, cinnamon, chain fern, and royal fern may be found in these hammocks.



Cinnamon fern

Hydric hammocks provide nesting habitat for the southern bald eagle, osprey, and little blue heron. In addition, the barred owl, red-shouldered hawk, blue jay, cardinal and wild turkey can be seen feeding in this area.

Mammals found in these scenic wetlands include gray fox, striped skunk, gray squirrel, black bear, opossum, bobcat and raccoon.

Numerous reptiles such as the five-lined skink, the box turtle and the yellow rat snake can be found here.

Moisture in these wetland communities comes from wet season flooding, rainfall and seepage of ground water from the uplands.

Although hydric hammocks may be flooded for only a month or so during the year, their soils may stay wet much of the year. The organic material from decomposing leaves mixes with the sand and silt.

This rich organic soil absorbs water like a sponge during the rainy season and slowly releases it during the dry season. Hydric hammocks are generally found between edges of the flatwoods or other mesic communities and the river swamps.

Cypress Domes



Cypress dome swamps are characterized as shallow, forested,

circular depressions which have a dome shape. This shape is due to the fact that the shortest trees grow in the shallower water at the outer edge while the tallest trees grow in the deeper water in the center. This difference in growth results from the constant stress caused by periods of drought and fire.

Pond cypress is usually the dominant plant. It

differs from bald cypress in that it has smaller, tighter needles and a slower growth rate. Other trees include red maple, dahoon holly, swamp bay, sweet bay, and willow.

The understory consist

of cinnamon fern, royal fern, chain fern, poison ivy, wax myrtle, button bush, green brier, and lizard's tail.

Cypress domes develop in sandy flatwoods or

sandhills where the surface has slumped as a result of a shallow sinkhole. The soil is a thick layer of decomposing plant material called peat. The subsoil is usually a layer of sand on top of limerock. Some cypress domes have a clay or hardpan layer between the sand and the rock which helps retain water.

Cypress domes receive most of their water by

seepage through the sand of the surrounding uplands. Most are closed ecosystems. Most water loss is by evapotranspiration by the plants. Some cypress domes are connected to other wetland systems by creeks which only flow during the wet season.

Fire plays a role in the survival of a cypress

dome community. Fires normally invade the outer edges of the domes about every five years. The wet interiors are normally burned only once in a 100 years when the dome is completely dry. The more frequent fires at the edges occasionally kill the outer trees thus maintaining the dome shape.

Cypress Domes (cont.)

Interiorofcypressdome

Cinnamonfern



Source: USGS cross section of a cypress dome

Cypress domes may have an open pond or

marshes in their center. This gives them a donut shape from the air. This area is too deep for young cypress trees to survive.

Alligators will sometimes use this pond as a

home. As the water level falls during the dry season, the alligator will deepen the hole thus preserving a water source for other animals.

D

uring the wet season these ponds are ho

mes for frogs, water snakes, turtles, and small

fish. They also host crayfish, dragonflies, damselflies and a variety of other aquatic insects.

Photo by Jason Chilson

Emergent plants such as pickerelweed and fire flag may grow around the edges of the pond. Water lilies may grow in the center.

Many cypress domes have been eliminated

from the landscape. The cypress logs cut from the small pond cypress make excellent fence post. Today, cypress domes are protected by state law. They are included as part of conservation areas in many new suburbs.

Photo by Jason Chilson



Wet Meadows / Wet Prairies

wet meadow Wet meadows and wet prairies are found in shallow depressions throughout the watershed. They are similar except for size. Wet meadows are small features which are found in upland communities. Wet prairies are larger features which may contain islands of upland vegetation.

Wet Meadows Wet meadows are wetlands which are dry for most of the year. They are often found in small shallow depressions within upland communities. These communities contain plants that can handle both wet and dry conditions. They usually have a very thin layer of organic material which may partially cover white sand. Due to the surrounding uplands the soil in these communities are usually acidic. Common plants include wire grass, hat pin, meadow beauty, beakrush, and carnivorous plants such as the sundew. Wet Prairies

Most wet prairies grow on sandy soils with thin layers of organic material. The upper soil is usually white to light gray sand to a depth of 34 inches, with a white or bright yellow subsoil. There is often a thin organic layer on the surface produced by the decomposition of plant material during the wet season. The soils are usually slightly acidic and are composed primarily of quartz grains.

During the rainy season, these communities

are covered with water up to a depth of 4 feet. Typically, wet prairies merge with freshwater marshes. They often contain scattered islands of open pine woods and hammock vegetation. As with many other communities, the distribution of species is influenced by the surrounding communities. Common plants include sand cordgrass, hatpin, beakrush, madencane, smartweed, and St. John's wort.

wet

prairie

Wet Meadows /

Wet Prairies (cont.)

During extremely dry periods old field plants

such as dog fennel or broom sedge may become abundant. Drainage of many wet prairie communities for development or pasture has prevented their progression towards marsh communities.

Wet meadows and prairies are an important



home to a variety of amphibians and reptiles. Many types of frogs and toads rely on the water in these systems to lay their eggs. During the wet season the pools of water are thick with tadpoles.

Sandhill cranes use wet meadows and prairies

as hunting and nesting grounds.

sandhill crane A variety of aquatic insects call these types of

wetlands home. Dragonflies and damselflies take advantage of the seasonal ponds to reproduce.

Crayfish

C

rayf

ish are common in many wet meadows and wet prairies. They are important food items for a wide range of wet meadow and wet prairie predators, including wading birds, raccoons, alligators, turtles, snakes, larger frogs, and fishes.

READING Lesson 3


ecological communities within the hillsborough river...

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