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Prairie Factors Maintaining Prairie 1.Low Rainfall 2.Fire 3.Grazing Each of these factors inhibits the growth of woody plants (trees and such) while.

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Presentation on theme: "Prairie Factors Maintaining Prairie 1.Low Rainfall 2.Fire 3.Grazing Each of these factors inhibits the growth of woody plants (trees and such) while."— Presentation transcript:

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2 Prairie

3 Factors Maintaining Prairie 1.Low Rainfall 2.Fire 3.Grazing Each of these factors inhibits the growth of woody plants (trees and such) while favoring the growth of grasses and other herbaceous plants

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7 Grasses in a Grassland Grass (Family Poaceae) are monocots and compose between 60% and 80% of plant species in a mature prairie habitats The three most common prairie grasses are: 1) Big Bluestem – Andropogon gerardi 2) Indian Grass – Sorghastrum nutans 3) Little Bluestem – Andropogon scoparius

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9 Fire & Growth

10 Grass Adaptations: Moisture They reduce their surface area by having narrow leaf blades with parallel veins that allow the leaf to curl further reducing surface area in harsh weather They prevent excessive water loss by having a waxy cuticle covering the leaves, hairy stems reducing wind and evaporation from the surface, small recessed stomata, and the C4 photosynthetic pathway They are also known for having roots that make up at least ½ of the plant that may reach 6 or more feet into the soil

11 Grass Adaptations: Fire & Grazing The growth tissue in a grass (meristem) is located below ground and is able to generate new tissue after being burnt or eaten They take in and store silica (sand) in their tissue in and effort to wear down the teeth of grazers Their seeds are stimulated to germinate by chemical produced from burning

12 Grass Adaptations: Other They do not rely on animal pollinators to mediate sexual reproduction. Instead their pollen is transported by the wind, a reliable component of the prairie They often reproduce through asexual means, by modified stem called stolons or roots called rhizomes that radiate, touch the ground, and grow into a new plant

13 I think the prairies will die without grass finding a voice. Its democracy may be against it. Prairie grass never seems to know anybody. William A. Quayle (1905) The Prairie & The Sea

14 Compared to trees, shrubs, or forbs, grasses seem unfathomably plain. They fail to inspire interest or stir the imagination. We look at prairie and we see a great emptiness, a void that staggers the psyche and leaves much too much for the mind to wonder. Randy Winter (1987) Nature Notes

15 Every American has the right as part of his cultural heritage to stand in grass as high as his head in order to feel some small measure of history coursing his veins and personally establish an aesthetic bond with the past. William E. Elder (1961) Needs & Problems of Grassland Presentation

16 Grass is the most widely distributed of all vegetable beings and is at once the type of our life and the emblem of our mortality…the carpet of the infant becomes the blanket of the dead. John J. Ingalls (1872) In Praise of Blue Grass

17 Grasses are the greatest single source of wealth in the world. Agnes Chase (1959) 1 st Book of Grasses

18 The basis of human proliferation is not our own seed but the seed of grasses. Evan Eisenberg (1989) Back to Eden

19 What a thousand acres of compass plant looked like when they tickled the bellies of the buffalo is a question never again to be answered, and perhaps not even asked. Aldo Leopold (1949) A Sand County Almanac

20 Grass Roots & Stems 1.Roots Fibrous and good as binding the soil 2.Stems Flowering stems or “Culms” are jointed with hollow internodes. A “Prophyllum” or modified first leaf of a branch that clasps the main culm, may support branching culms

21 Grass Leaves Grass leaves have parallel-veined blades that are usually narrow. A “Foliage” leaf has a “Sheath” that surrounds the culm, a “Ligule” that stands up at the junction of the sheath and blade, and the leaf “Blade” itself

22 Grass Flowers Grass flower clusters or inflorescences bear Scaly units called spikelets that are arranged as a: 1.Spike 2.Panicle 3.Spikelike 4.Raceme


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