Grassland Biomes Chapter 8

The land between the desert and the forest. 8.1 Grasslands Objectives Describe the characteristics of grasslands Identify where grasslands are located A grassland is an ecosystem where there is too much water to form a desert, but not enough water to support a forest. The land between the desert and the forest.

                

Grassland Climate A little wetter than the climate of a desert The desert-grassland boundary is the area between deserts and grasslands where increased rainfall enable some grasses to grow. This boundary shifts with long-term changes in climate patterns Rainfall is the most significant limiting factor in grasslands

Grassland Video

Grassland Organisms Grass is the most common Most of the mass of grass is below ground Grasses not as limited by factors such as rain and fires

Grass and Fires Natural grass fires play an important role Fires help prevent forests from overgrowing grasslands Fires help by burning away dead grass allowing more water and air to reach soil Fires help release valuable nutrients Germination of seeds is aided by fire

Animals Help Grasses Grazing animals help keep other vegetation from growing without harming grass Burrowing animals help to aerate the soil and by helping nutrients and water to reach the roots

Rainfall and Grasslands Types of grasses vary based on the amount of rainfall Irrigation important to cultivated grass crops When it rains is also important Some grasslands have rainy and drought seasons Some plants have become drought-resistant

Types of Grasslands Steppe (Chaparral) Prairie Savanna

8.2 Steppes and Prairies Objectives Compare and contrast a steppe and a prairie Describe the importance of steppes and prairies in agriculture Steppes are grasslands that get less than 50 cm of rain a year Prairies are grasslands characterized by rolling hills, plains, and sod-forming grasses.

Steppes and Prairies continued Steppes have very low rainfall and sparse plant life – almost a desert U.S. prairies are Called the Great Plains Large fertile areas where most food is grown Grains – breads and cereal Breadbasket

Steppe and Prairie Climates 25cm to 50 cm rainfall per year Rain evaporates quickly only reaching top 25 cm of soil Temperature range from –5 oC to 30 oC Prairie 50 cm to 75 cm of rain per year Sometimes much more rain and floods Rain usually as thunderstorms

Steppe and Prairie Organisms soil holds water well roots of grass (sod-forming grasses) form a mat called sod Humus is a layer of organic matter Holds water and provides nutrients and food

Steppe and Prairie Organisms Steppes Short grass prairies Mostly bunchgrasses – fine bladed grasses that grow in clumps Clumping helps save water by holding water in a small root area, under the shade of the grass.

Steppe and Prairie Organisms Animal adaptations Migration Hibernation Burrowing Plant adaptations Seeds and pollen carried by wind Spreads over a wide area

Buffalo

Steppe and Prairie Organisms Migrating grazers do little damage But poor farming and ranching practices cause extensive damage Overgrazing, poor farming practices combined with droughts caused the Dust Bowl n the 30’s. Today new techniques help reduce the impact

8.3 Savannas Define savannas, and state where they are located. Objectives Define savannas, and state where they are located. Explain how savannas can support a wide range of organisms. Savannas are tropical grasslands ranging from dry scrubland to wet open woodland.

Savanna Video

Savanna Climate Rainy seasons and long periods of drought As much as 150 cm rainfall per year Most falls heavily during thunderstorms Rest of year can be very dry Extreme climate demands a wide range of adaptations of organisms.

Savanna Plants Grasses, shrubs and trees must be resistant to drought, fires and grazing animals Many grow runners long horizontal stems above or below ground Grasses grow in tufts large clumps of tall, coarse grasses Thorns or sharp leaves Protects from grazing animals They grow rapidly to recover quickly

               

Savanna Animals Reproduce during rainy season when food is abundant Migrate to follow the rain Vertical feeding pattern Animals eat vegetation at different heights Can feed in the same area without competing Allows more animals to live on limited resources

The End

Quick Quiz 8QQ 1. Grasslands 2. Prairie 3. Steppe 4. Savanna Rhino Vertical feeding pattern Fire is important to health of the ecosystem Large areas with deep, fertile soils Mostly clumps of grasses with bare soil between Bison 50 cm to 75 cm of rain per year Climate wetter than a desert, but not as wet as a forest No real winter, but long dry season followed by intense wet season Grazing and burrowing animals help 4 1 2 3 Click Again for Answers