INDIANA DUNES NATIONAL LAKESHORE ENVIRONMENTAL EDUCATION
Secrets of Succession Program Outline
I. West Beach Parking Lot Introduction
A. self
B. park
a. Ask students, “Why are you here?”
C. applicable rules
D. program theme and purpose
a. This area is suited for the study of secondary and primary succession.
E. plan and length of the program are noted
F. resource management issue is introduced
G. safety concerns
II. Beach
A. brisk hike to the beach
B. introduction to the glacial origin story for Lake Michigan
C. Activity (-) Glacial Formation of Lake Michigan: Select a student to move a piece of styrofoam representing a continental glacier lobe carving out Lake Michigan, forward, representing glacial retreat. Mention that there were several advances and retreats, but it is not necessary for the students to do this more than once. Attach a blue towel or other blue material to the styrofoam such that as the ‘ice’ retreats, a lake forms. The motion of pushing the styrofoam forward and backward should be combined with a downward pushing motion to carve out a depression and produce lateral and terminal moraines.
(0) Cover the above topic while drawing the glacial history in the sand yourself. Draw in the sand the story of the glacial history of the area. Students can assist in the drawing. Build a large glacier out of sand, explaining that 12,000 years ago a glacier one mile high and many miles across covered this area. Have the group or individual move the sand forward, showing the glacier advancing. Then move the sand backward, showing the glacier retreating. Build or draw resulting moraines, ancient Lake Chicago, and various shorelines, explaining their formation.
(+) Briefly explain the glacial history of this region
D. Activity: Explain the concept of ecological succession and describe its manifestation here in the dunes. This is a place where many special types of plants and animals live. They do this by adaptation. Does everyone know what adaptation means? Change is the key word. Some plants and animals change their home so much that they can’t live there anymore and then others move in.
Communities consist of plants and animals either directly or indirectly depending on each other for survival.
(-)Succession Play: Most of the class participates in a succession play wherein one or more students are the dune-makers shoving up dunes as they are moving backward toward the lake, and then shoving up more dunes. Another pair of students then plant marram grass symbols, following along behind the dune-makers. On the heels of the marram grass planters are the cottonwood jack pine, and black oak planters. Students representing death and decomposition remove marram grass, cottonwood, or jack pine when black oak grows near. They also sprinkle dark ý on the black oak forest to symbolize soil development. In this way students have been personally involved in the process of succession. As the skit unveils itself, the ranger conducting the tour narrates the process. The students will then proceed to see what they have enacted first-hand.
(0) The ranger draws in the sand to describe the process of succession in the dunes. Draw Lake Michigan, showing waves and currents washing ashore sand and depositing it on the beach. Build the first row of dunes planting dead marram grass blades into the dunes. Discuss how the marram grass captures the blowing sand to form dunes. Build a second row of dunes closer to Lake Michigan. Plant marram grass in these. Add cottonwood twigs and other dead grasses to this dune. Explain that this dune is being sheltered by the other dune ridge making it a more hospitable environment for more kinds of plants to grow. Build another row of dunes closest to Lake Michigan. Plant marram grass in these. Add cottonwood twigs to the previous dune and oak tree twigs to the first dune ridge removing the cottonwood and marram grass. Explain that the cottonwood and marram grass died and decomposed. Conclude the activity with a discussion on the changes in the first dune over time. As it became more sheltered, shaded, and warmer, it formed an environment for oaks to thrive in. Also, as more plants and animals decomposed, humus built up, enriching the soil and making it more suitable for oaks.
(+) Draw in the sand to demonstrate what happens in the process of ecological succession in the dunes.
a. Still on the Beach, explain to the group that they will be divided into small groups of 4 or 5 to measure light intensity, wind speed, wind direction, soil temperature, air temperature, soil moisture, and water percolation rate for four biological communities (beach, foredune, jack pine forest, and oak forest). Based on these measurements, they will make some general statements concerning the effect of abiotic factors and plant communities on the process of succession and vice versa. They will also take an inventory of plants and animals found in each community.
(-) They can also take and record the pH of the lake, mentioning the impact of acid rain on the lake organisms. The lake pH is usually 6.
III. Foredune – Cottonwood Community
A. There is rarely more than a trace of humus. Mostly have animals which breed below the surface of the sand. They are diurnal and predatory.
B. Examples are tiger beetle, sand !, maritime grasshopper, long-horned grasshopper, burrowing !, long-horned borer, juniper and bearberry
C. Activity: Abiotic Factors and Organism Lists: (-, 0, +) Take measurements and inventory the plant and animal life. Take readings off the first staircase of the Dune Succession Trail where a spur leads to the beach or along the trail as it continues toward the jack pine forest. Make measurements in the grasses along the trail, avoiding the jack pine forest because it is coming up in the next community.
Explain that grasses and cottonwood trees are pioneers building dunes and continuing the process of succession.
D. Root Systems (-, 0, +) Hold up a string with strings attached to it in a standard root system configuration. Then hold up a string arranged as in the rhizomes of marram grass. Ask which pattern would hold the sand together better and contribute to more stability and soil-building. This illustrates the marram grass rhizome system for holding dunes together.
IV. Jack Pine Community
A. Here the humus is considerably darkening. Mostly contains animals which require cover and less shifting sand. Pine is not easily decomposed or palatable to earthworms because of its high amounts of lignin, a substance combined with cellulose which forms the strong cell walls of plants. Pines have low requirements for many nutrients, so they are well adapted to primary and secondary succession on poor soils.
B. Examples here include digger wasp, tiger beetle, six-lined racerunner, blue racer, ground squirrel, pitch moth, and juniper
Activity: Abiotic Factors and Organism Lists: (-, 0, +) Groups complete the plant and animal inventory and measure abiotic factors.
A. Activity: Required Environments (-) Students are selected to symbolize environmental factors: wet, dry, sunny, shady, oak forest soil, beach soil, warm, cold. Other students wear tags representing plants or animals: hognose snake, deer, marram grass, oak, cottonwood, jack pine, prickly pear. Two at a time, have opposing environmental factors highlighted; each animal or plant is asked to group around the factor most favorable to them. As it progresses and after completion, discuss the importance of environment and how required environmental factors contribute to the process of succession.
V. Interdunal Pond
A. Activity: Nothing Lasts Forever (-,0,+) Ask “Is this pond a climax community? Is the lawn in your yard? Once a climax community is achieved, is it forever? What can cause succession to start over again?” See how many factors the group can name which can initiate or interrupt succession. (fire, flood, glaciation, human development, agriculture, logging eruptions).
Use the pond and blowout as an example of an interruption in the process of succession. Define and discuss the factors causing the formation of this blowout and pond. A fallen log or development of an informal trail by humans may have allowed the wind to blow out this bowl-shaped formation. The wind scored out the sand down to the water table, allowing an Interdunal pond to form.
Discuss other newsworthy examples of interruptions in succession.
Identify the plants and animals that live in the blowout and Interdunal pond area.
B. Activity: Time-spans (-,0) Unroll a string with attached labels. Enlist the aid of students to stretch out the string. The beginning of the string is 0 time. The total length of the string is a 50’. 50’ represents 5,000 years. Labels along the way indicate various animal life spans. Include bristlecone pine, 5,000 years, cottonwood tree, oak tree, marram grass, people, 100 years, deer 20 years, frog, mosquito. Describe how life spans contribute to the process of succession. Repeat the activity with another string representing 1,000,000 years. Indicated along the string are the glacial age, production of the dunes, and establishment of the lakeshore.
C. (0) Unroll a string with only the lifespan (year) labels attached. Pass out the plant and animal labels. Have students attach these labels to the life span labels. Unroll a string with correctly placed animal/plant labels. Compare the students’ timeline with this timeline.
D. (+) Pass out plant/animal cards and have students hold the unmarked 50’string at the point that represents the life span of their plant or animal. Remind them that 50’ of string represents 5,000 years. Unroll a string with correctly placed labels. Compare the students’ timeline with this timeline.
Discuss how organisms occurring earlier in the succession process tend to have shorter life spans.
VI. Black Oak Forest
A. Climb the stairs to the black oak forest.
B. Much darkened humus. Locally covered with a “dry moss” or dried leaves.
C. Examples now include leaf cutters and root borers, tree fogs, hog-nosed snake, tree cricket, stink bug, and red squirrel
D. Activity: Abiotic Factors and Organism Lists (-,0,+) Groups complete the plant and animal inventory and measure abiotic factors. The results from all of the measurements are collated and discussed. Trends are observed.
E. (-) As a group, discuss the trends in abiotic factors they measured. Ask leading questions as necessary to assist the group in drawing accurate conclusions.
F. (0) Have each group present conclusions in the trends shown by an abiotic factor.
G. (+) Have each group present the results of their measurements and listing of organisms. They should discuss the trends for each of the abiotic factors and in biodiversity as we move from early to later successional stages. (Biodiversity increases throughout in this case. In other cases, biodiversity will often increase and then decrease as the climax community is reached.
H. (-,0,+) The sand-mined area visible from the viewpoint is discussed as it relates to human influences on the process of succession.
VII. Conclusion Activity: (-, 0, +) Review. The process of succession is reviewed. The following terms are discussed: succession, community, sere, climax community, primary and secondary succession. Examples of human impact on the dunes, and their consequential influence on dune erosion and the process of succession are stated. Examples of actions to reduce human-induced dune erosion are given. The importance of people allowing natural processes to occur is realized.
Activities were created for three educational levels to meet needs of varied groups. Activities are coded (–) for beginning level; (0) for average level; and “+” for advanced level
Activities: Abiotic Factors and Organism Lists
(-) Take measurements as a class; lead the class to conclusions when comparing and contrasting measurements and animal and plant inventories of biological communities. Ask the group why there are few or no plants growing on the beach. Because of adverse environmental conditions such as constant wash of waves and human impact.
(0) Divide into groups of 4 or 5; each group takes measurements of each community. Ask leading questions if necessary to help them draw conclusions. Assign each group to present conclusions concerning one of the abiotic factors measured and the changes which occurred from beach to oak forest. See appendix for desired group conclusions.
(+) Suitable for groups such as “Metro” or others who know the area well. Divided up into groups of 4 or 5. Assign each group to record abiotic measurements and a plant and animal inventory in a different community. Provide field guides to allow participants to identify plants and animals on their own. Each group should give a class presentation on their community findings. All community information should then be compiled and each group given time to study and present reasons for differences in plants and animal composition and differences effect and are effected by succession.
Note: Demonstrate the use of instruments by taking measurements at the beach or another community. Have each group take readings on the upper beach and check their findings for accuracy and proper equipment use.
Gain the cooperation of teachers, other leaders, and parents. Ask them to assist groups with measurements. Distribute tool kits, keeping group size to four or five.
Go through the plant and animal inventories also. For beginner groups, have them list kinds of plants instead of specific names. In the foredune, they might list ‘trees, grasses, and shrubs” and in the oak forest “trees, understory trees, shrubs’. There will still be excellent value in this exercise for the group.
Activities: Pick a Route – The goal of the technique involves the students and makes them feel they are helping direct the field trip.
This technique works best in the area behind the West Beach Visitor Center and picnic ground. You can start this technique in the parking lot. Show the group two different routes they could take and have one student choose the way. At each stop offer two or three options and allow another student to choose. Soon all the students will want to pick the route.
A couple of tricks to lead the group where you want to go are 1) when you describe the two routes lead, make one sound more attractive. 2) If they choose the less desirable route, then start on that trail and slyly circle around.
Caution: You give up some of the control of the program so you need to be adaptable.
Secrets of Succession combining art and ecology activity.
Some of America’s most famous naturalists looked at nature more closely through art. Their notebooks and journals are full of pictures of plants, animals and scenes from nature.
It can be difficult to find a technique that gets seventh and eighth grade students involved in your program. Some teachers prepare the students well so you may be left wondering what else to try. Try challenging the students to look, listen, and feel at each of the four communities they visit on the succession trail so they can put down in words or art what they observe.
Materials: Cardboard backing boards, two 4x6 index cards per student, pencils.
At each community allow the students to chance to discover something that interests them. It might be shoreline tracks, marram grass partially buried in sand, or an overall view of the dunes and lake. Give them choices to draw or write a poem about what they experience or how they feel.
If you want to structure the observations, ask them to summarize the community in tow or three words or give it a title. In one corner of their index card they can record their observations of the environmental factors of each community such as soil moisture, wind, sunlight, plus air and soil temperature. To save paper, use one side of the index card for each community.
Allow the students to break up into groups of four. Have each student share what he or she drew or wrote with the other students in the group. At each community have the students form new groups so they can share what they wrote or drew with different people.
You still need to tie this art and poetry to the ecology of the communities. You can hit on the theme about how one community can change the environment to allow another community to grow. They can refer to their description of the environmental factors to make comparisons.
This method offers these benefits:
- They will increase their observation skills when they look at the community to write or draw.
- A student can discover something that interests him or her.
- There can be more questions as the students look closely at the community.
- The sharing breaks down the wall between a presenter and the participant. You will get to know some of the children as individuals.
- You are encouraging cooperative learning through sharing.
- Science can be a cold subject but discovering things that interest the student can bring meaning.
- The science is still there if you plan your presentation to hit the highlights of succession and each community. Granted the depth of knowledge is not the same. Give the teachers a chance to build on that knowledge back to the classroom.
When this technique was tried on seventh and eight grade students they liked it. There was good cooperation in the groups. The teachers were proud of the poetry and artwork. The teachers and chaperones were involved and shared their feelings in the groups with the students. Use this technique as one of the approaches to Secrets of Succession.
I. ORGANISM LIST
- UNDISTURBED UPPER BEACH
1. PLANTS
a. Sea rocket. Annual with fleshy stems and glossy leaves which hold water.
b. Bugseed. Also called tumbleweed. Narrow pointed leaves conserve moisture by reducing transpiration and incident solar radiation.
c. Cocklebur. Coarse, scratchy texture helps retain moisture.
d. Winged pigweed. Sharp pointed holly-like leaves help conserve moisture.
e. Seaside spurge. The plant grows close to the ground to protect itself from the wind and resulting moisture loss.
2. ANIMALS
a. Ring-billed gull.
b. Herring gull.
c. Carrion flies.
d. Raccoons
e. Sanderlings
f. Spotted Sandpipers
g. Robber flies
h. Tiger beetles. Scavengers who dine on remains of fish, birds and insects washed ashore by waves.
- FOREDUNE – COTTONWOOD COMMUNITY
Notes: Windward slopes of moving dunes have less vegetation than leeward slopes. South-facing (leeward) slopes are sheltered from the wind and receive more sunlight. This accounts for the differences which can be seen in otherwise similar habitats.
1. PLANTS – these plants are pioneers which build the dunes.
a. Marram grass. The stems sprout roots to absorb water. The roots (rhizomes) send up leafy sprouts to the surface to form new plants. Root networks capture and hold sand grains in place forming dunes. The appearance is somewhat like that of uncombed hair. Rhizomes that break away can start a new plant up to a mile away. The plant can elongate its stem during sand burial.
b. Sand reed grass. Sand reed grass has shorter rhizomes that marram grass and lacks the ability to elongate its stem with rapid sand burial. Rhizomes dive deep for moisture.
c. Prickly pear cactus. Round fat pads with needles conserve and hold abundant moisture.
d. Sand thistle. This endangered species has thorn-tipped leaves that are deeply lobed and narrower than other thistles.
e. Cottonwood trees. These trees need sheltered, damp depressions to sprout, but avoid being easily smothered by sand or drowned by water because new roots can grow from stems nearest the surface. Coarsely toothed triangular leaves hold moisture efficiently. Cottonwood trees build dunes by holding sand in place.
f. Little bluestem. The plant sprouts from seed and has unlimited elongating ability and no underground runners.
g. Sand Cress. This plant is much smaller than its relatives. The upper leaves are sparse.
h. Sand cherry. This shrub spreads by underground runners. It has narrow leathery leaves to conserve water. It helps hold dunes together after the initial bonding by marram grass.
i. Horsemint
j. Goldenrod
k. Hoary puccoon.
l. Milkweed
m. Evening primrose
n. Poison ivy.
o. Riverbank grape.
p. Bittersweet
2. ANIMALS
a. Velvet ant. This insect preys on digger wasps. It has a fine hair-like covering to insulate it from moisture loss.
b. White tiger beetle. This insect lives in burrows underground. It forages by day because its light color reflects heat.
c. Burrowing ! This arachnid lives in burrows underground.
d. White grasshopper. This insect forages by day because of its light color, which reflects heat.
e. Digger wasp. This insect protects itself by interrupting its burrow-digging process by darting upward a foot between each digging thrust (to where the air is 10 degrees cooler than the sand’s surface).
f. Ant lion. The larvae rest just below the sand surface at the base of conical depressions while awaiting their prey (which falls into their pit).
g. Field sparrows and chipping sparrows. Grasses and berries provide food for these seed-eaters.
h. Snout beetle. This insect eats dune grasses.
i. Killdeer. A bird which eats snout beetles and grasshoppers.
j. Short-tailed shrews.
k. Deer mice.
l. Six-lined race runners (lizards).
m. Fowler’s toad.
- JACK PINE COMMUNITY
1. PLANTS
a. Jack pine. Well-adapted to cold and harsh climatic conditions, jack pine needs only small quantities of soil nutrients (such as calcium). Cones open and disperse seeds in response to heat reflecting off light-colored sandy soil. The outer ‘skin’ of their needles is thick; it forms half the bulk of each needle. Stomata openings are sunk deep into each needle’s lower surface.
b. Common juniper.
c. Red-Osier dogwood.
d. (Arctic) Bearberry. This low growing shrub spreads by growing new shoots from runners underground. It survives slow sand burial. It provides ground cover to protect young pine trees from the wind and blowing sand.
e. Hop tree.
f. Dune grasses.
g. Flowers of the foredunes.
h. Riverbank grapes.
i. Poison Ivy.
j. Bittersweet
k. Starry false Solomon’s seal.
2. ANIMALS
a. Burrowing and crab spiders.
b. Black ants.
c. Six-lined race runners.
d. Blue racers.
e. Garter snakes
f. Bronze tiger beetle. Feeds on the resin of new pine shoots.
g. Pitch moth. Feeds on the resin of new pine shoots.
h. Long-eared and great horned owls. These nocturnal birds seek the cover of evergreens in winter.
i. Evening Grosbeak. This and the birds listed below migrate through or seek shelter here during the winter.
j. Chickadee
k. Pine siskin.
l. Red crossbill.
- BLACK OAK COMMUNITY
NOTES: Once oak trees take hold, they permit nutrients not needed for their growth to leech away and leave a soil which is too nutrient-poor for beech trees to grow in. Beech trees need mineral-rich humus. Therefore, the theoretical final climax stage of beech maple may never occur at West Beach.
1. PLANTS
a. Witch hazel. This plant flowers in the fall after the previous year’s seed pods have burst open.
b. Black oak.
c. Basswood.
d. Sassafras.
e. Virginia creeper. This vine has leaves which are arranged in leaflets of five.
2. ANIMALS
a. Raccoons
b. Skunks.
c. Red and gray squirrels
d. Chipmunks
e. Woodchucks
f. Cottontail rabbits.
g. White-tailed deer. Deer are able to find hiding placed in the cover of the climax oak forest. Food is mostly obtained in open areas where forbs grow, such as around wetlands or in meadows where disturbance has occurred (such as fire).
h. Birds of the treetops (including scarlet tanager, great-crested flycatcher, and red-eyed vireo).
i. Birds of the underbrush (including the brown thrasher, cardinals, and kinglets).
j. Birds which feed on the ground (including towhees, robins, ovenbirds, and wood thrushes).
k. Organisms of decaying logs (including earthworms, millipedes, centipedes, crickets, beetles, and carpenter ants).
- BLOWOUTS
1. PLANTS
a. Blowout plants. Thriving in blowouts are cottonwoods, sand cherry, willow, and red osier dogwood.
b. Willow. Willows resist evaporation/transpiration by maintaining long, narrow leaves which expose as little as possible surface area to the sun. The furry dune willow has wider leaves which hold moisture thanks to a thick downy covering on the leaves and stems. Blue-stemmed willow has leathery leaves which reflect light and heat and resist the drying effect of wind (by creating a dead air space close to the leaf).
c. Scouring rush.
d. Wormwood.
e. Hoary puccoon.
f. Common milkweed
g. Sand thistle
h. Wild rye
i. Horsemint
j. Goldenrod
k. Flowering spurge.
l. Jack pine.
m. Juniper.
n. (Arctic) Bearberry.
2. ANIMALS
a. Velvet ant. This insect preys on digger wasps. It has a fine hair-like covering to insulate it from moisture loss.
b. White tiger beetle. This insect lives in burrows underground. It forages by day because its light color reflects heat.
c. Burrowing !. This arachnid lives in burrows underground.
d. White grasshopper. This insect forages by day because of its light color, which reflects heat.
e. Digger wasp. This insect protects itself by interrupting its burrow-digging process by darting upward a foot between each digging thrust (to where the air is 10 degrees cooler than the sand’s surface).
f. Ant lion. The larvae rest just below the sand surface at the base of conical depressions while awaiting their prey (which falls into their pit).
g. Field sparrows and chipping sparrows. Grasses and berries provide food for these seed-eaters.
h. Snout beetle. This insect dines on dune grasses.
i. Killdeer. A bird which eats snout beetles and grasshoppers.
j. Short-tailed shrews.
k. Deer mice
l. Six-lined race runners
m. Fowler’s toad.
- INTERDUNAL PONDS
1. PLANTS
a. Sedges
b. Common cattail.
c. Bulrushes. These plants grow in neat rows, due to a stout creeping rootstock (stolen) which tends to grow in a straight line.
d. St. John’s Wort
e. Stiff Aster
f. Purple Gerardia
g. Rose Pink
h. Kalm’s lobelia
i. Yellow horned bladderwort. The bladders of this plant are tiny hollow sacs which project from its underwater leaves to capture water fleas.
j. Ladies’ tresses.
2. ANIMALS
a. Water treader
b. Water strider
c. Water boatman
d. Whirligig beetle
e. Damselfly
f. Dragonfly
II. DEFINITION OF TERMS
A. CLIMAX COMMUNITY. The final, most mature and stable community (sere) possible under existing environmental conditions.
B. COMMUNITY A group of plants and animals which thrive and work together in a specific area.
C. GLACIER A sheet of moving ice which lasts through the yearly dry period. Continental glaciers, such as the one which produced Lake Michigan, were a mile thick and covered Indiana Dunes 12,000 years ago. When they melted, this formed the shoreline of ancient Lake Chicago (present day Lake Michigan).
D. MORAINE. Rock material of variable size deposited in a ridge by retreating glaciers at their sides (lateral moraine – Sleeping Bear Dunes) or front (terminal moraine – Indiana Dunes area).
E. PRIMARY SUCCESSION. The change in vegetation and animal life over time which naturally occurs as one community is replaced by others. Primary succession begins on barren soil.
F. SECONDARY SUCCESSION. The change in vegetation and animal life in a community which occurs after a human disturbance or a major event such as a fire, flooding, or volcanic event. Secondary succession occurs on formerly vegetated areas.
G. SERAL STAGE. A community in a successional series. The entire sequence of communities is known as a sere.
H. SUCCESSION. The changes in vegetation and animal composition over time through which one population or community is replaces by others in the same location. The process produces a sequence in community types from pioneer stages to a mature or climax community, unless the process is interrupted. The process of succession is often interrupted.
DI. GENERAL CONCLUSIONS
A. .LIGHT AND MOISTURE
1. Moving from beach to oak forest, the amount of sunlight decreases. This is due to the community plant composition. Near the lake, sun tolerant cottonwoods and grasses are found. In the oak forest are found shade tolerant oak, witchhazel, and other broad-leaved trees and shrubs.
2. Sunlight, evaporation, and transpiration decrease from beach to oak forest; the amount of moisture available to the soil increases. Since there is a greater quantity of organic material in the soil progressing from beach to oak forest, the soil is more capable of holding moisture.
3. The vegetation controls the amount of sunlight striking the ground. As the plants grow, they create shade, which modifies the light and moisture conditions on the ground. Trees are sometimes observed with unusual bent or twisted growth patterns resulting from their competition for available sunlight.
4. Percolation rate is highest in the beach and dune community, due to the sandy soil and lack of organic material. Organic materials accumulate gradually through decomposition of plants and animals which die. Porosity, structure, and texture of soil all work together to determine percolation rate. A greater assemblage of decomposing organisms increases the rate of decomposition and resultant organic material on the ground surface. This enables greater retention of moisture.
B.TEMPERATURE RANGE
1. As moisture increases and sunlight decreases from beach community to oak forest community, soil temperature decreases. This results in greater plant diversity, as a more tolerable living temperature range is achieved. On the beach, the temperature range may be as large as 0 degrees to 120 degrees Fahrenheit. The soil temperature range is smaller. Less fluctuation in temperature creates less stress for plants, enabling a greater variety of plants to grow successfully.
DII. MOISTURE LOSS FROM LEAVES VERSUS PHOTOSYNTHSIS
Plants have specialized surfaces, such as waxy cuticles, hairy coverings, or a leathery surface. Leaves may be held at an angle to the sunlight to reduce incident sun and moisture loss. This allows plants to conserve moisture and to survive in desiccating conditions (windy areas, sunny areas, xeric soil areas) as are found on the beach or in the foredune – cottonwood community. Plants also reduce leaf surface area to conserve moisture. This is done by growing leaves which are narrower. In the climax oak forest community, where wind and sunlight are decreased, moisture retention is not as much of a problem. Plants tend to have larger leaves, which provide a greater surface for incident sunlight, which feeds the process of photosynthesis.
DIII. STRATEGIES FOR SURVIVAL FOR DUNE GRASSES, WHICH BIND SAND INTO THE BEGINNINGS OF SOIL
Dune grasses have adapted ways to reproduce and spread. They may have underground runners and the ability to shoot up new stems to prevent sand burial. Others produce enormous quantities of seeds which travel by wind. In the foredunes, a greater part of the plant is underground. This enables plants to capture and hold sand in place to build dunes.
DIV. SOIL CHARACTERISTICS, ENRICHMENT AND Ph
1. Pioneer species take over a disturbed area. As plants decompose, the soil is enriched, allowing other species to take over (gradually over time).
2. Soil influences the types of plants which can grow. Soil moisture, amount of organic material, pH, temperature, and soil texture and structure are all factors which affect plant growth. Foredune soil is neutral (has a pH of 7). The oak and jack pine forest soil is acidic, due to the presence of pine needles and tannic acid from oak leaves. Pine trees decompose materials into nutrients for their own use. Thus, nutrients do not build up and the theoretical climax of beech cannot grow.
3. The soil tends to become darker (with greater amounts of organic material and higher moisture levels) as we progress from beach community to oak forest community. Darker soil absorbs and holds greater heat, while lighter soil reflects more heat.
4. In the microclimate of the first 1.5” of soil, there is generally more heat and more moisture. To germinate, seeds need proper light, water and temperature levels. Most seeds require a narrow temperature range (of about 5 degrees) to germinate.
VII.GENERAL COMMENTS ON SUCCESSION
1. Succession is a gradual process over time. There is much overlap of species between environments.
2. The life span of pioneer species is shorter than that of climax forest species.
3. Succession is a world-wide phenomenon, occurring in deserts, tropical forests, coniferous forests, tide pools, and prairies.
4. Bodies of water are temporary in terms of geologic time. Dynamic physical events, such as glaciation, human-built dams, or earthquakes are necessary to maintain them. All bodies of water are presently disappearing through the process of succession or other geologic events, unless geologic factors are maintaining or enlarging them.
DV. INSTRUMENT INSTRUCTIONS
A. IMPORTANCE OF PROPER USE OF INSTRUMENTS
Insuring that the students are using the instruments properly is just as important as insuring that they are taking measurements in appropriate areas. For example, the light intensity should be taken in a sunny area on the beach, not in the shade of a cottonwood tree. Also, the soil moisture, soil temperature, percolation rate, and wind speed of the jack pine forest should be taken off the trail just before the start of the boardwalk that leads to the oak forest. This will more closely approximate the actual sheltered conditions in the jack pine forest. Choose representative areas not far off the trail, cautioning students of the poison ivy and reminding them to keep trampling of vegetation to minimum,. Emphasize that the group is responsible for the equipment; they should handle it carefully.
B.USE OF INSTRUMENTS
1. Light Intensity – Switch the button on the Instamatic Duo Light and Moisture Meter to “Light”. Hold the meter level in your hand and point it at a representative site. Use the lower scale to record relative light intensity that ranges from “A” (low) to “H” (high). Logically, light intensity will decrease from the beach to oak forest.
2. Soil Moisture – Using the Instamatic Duo Light and Moisture meter, switch the button to “water” and insert the attached probe into the soil about one inch, to the white marking. Read the upper scale that ranges from “1” (dry) to “8” (wet). Record this reading. Then insert the probe into the soil deep enough so that only the white handle is above the ground. Record this soil moisture.
3. Wind Speed and Direction – Face the wind and hold the wind meter in front of you in a vertical position and with the scale side towards you. Do not block the bottom holes with your hand. Pan (move) the wind meter back and forth in the direction of the wind. The height of the ball is the low range wind velocity in miles per hour. To obtain the high range wind velocity, cover the red hole at the top of the meter with your finger. Record the average of the low and high range. Also, record wind direction. If the wind meter needs cleaning or the ball sticks, use the pipe stem to clean out the tube. Wind velocity will be highest at the beach and lowest in the oak forest.
4. Soil Temperature – Take the black holder off the round dial temperature gauge. Poke the gauge one inch into the ground to read and record the temperature in Fahrenheit (outside numbers on the dial). Then grasp and cover the dial with the palm of your hand and stick it into the soil until the dial is resting on top of the soil. Record the temperature. The first one inch of soil is a microclimate that holds daily heat. Soil color at this depth affects the amount of heat held. Temperatures at this level will affect germination. Less heat will be held in the beach microclimate than in the oak forest microclimate. Further down in theý, where temperatures are cooler and more uniform, the plant roots will search for moisture. Soil moisture at this depth will determine temperature. Temperatures at this level affect growth.
5. pH – Test and compare the pH of Lake Michigan and the intradunal ponds. Dab a drop of water onto the un-numbered center yellow square (between #6 and #7) on the pH paper strip. Match the color of the square with the colors numbered 1 – 12 indicating whether the water is acidic (1-6), neutral (7), or alkaline (8-12). Lake Michigan’s pH is around 6.00. The foredune pH 6.11; cattail marsh 6.50; red maple swamp forest 6.75; bog average 3.6; fen average 6.5; inside pitcher plants 6.5-8
6. Percolation Rate – The amount of water that filters through the soil depends on the soil type and present moisture. Some soils, like the oak forest soils, hold more water because water is able to adhere to the surface of their particles. The sandy soil of the beach and foredunes has smooth surfaces that don’t allow water to stick to them easily, causing the percolation rate to be faster. Percolation rate should be slowest in the jack pine and oak forest.
Push the tin can two inches (up to the blue mark) into the ground. Pour one cup of water into the can and time the number of seconds it takes for all the water to move into the soil. Record the percolation rate.
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