Environmental Biology - Grasslands



Succession - climate & soil - productivity of biomes

Grasslands- Prairie - Tundra - Savanna

Plant Nutrients - Water - Carbon Dioxide - Nitrogen - Phosphorous - Magnesium -

Sources of Minerals - Fertilizers - Mineral Availability - Epiphytes - Agriculture




This unit covers biomes, grasslands,  and plant nutrients. Before considering grasslands, we will first examine biomes (grasslands being one example of a biome), and succession, the process by which a grassland becomes a forest.

Note: These notes are a skeleton, which  your instructor will embellish with anecdotes and illustrations, both verbal and visual during lectures. Therefore, reading these notes is not a substitute for coming to class!!!


Biomes - a major biotic community having well-recognized life forms and a typical climax species






1. Primary succession

2. Secondary succession

General trends in succession:





This table summarizes the differences between pioneer and climax communities:

 Pioneer Community                Climax Community                          

 Harsh environment                favorable environment                     

 biomass increasing               biomass stable                            

 energy consumption inefficient   energy consumption efficient              

 some nutrient loss               nutrient cycling                          

 low species diversity            high species diversity                    

 fluctuations common              fluctuations less common                  

 r - adapted                      K - adapted                               

Climate and soil - effects on biomes

Biomes are largely determined by combination of temperature and rainfall:

(See Figure 3.6 page 38 in Levine and Miller)

Be sure to look at the figure 3.18 in Levine and Miller to learn where the biomes are located in the world!

On quizzes and tests you may have to fill in a map with the appropriate biomes.

Productivity of biomes:


  1. estuaries and tropical rain forest
  2. temperate forest
  3. agricultural land
  4. temperate grassland
  5. lakes and streams
  6. coastal zone
  7. tundra
  8. open ocean
  9. desert

It apparently takes two main factors to make a productive biome - water and sunlight.


Grasslands have more than 20 cm rainfall/year but not enough precipitation to support trees. Grasslands may occur in slightly wetter areas with frequent fires; there is some evidence that North American prairies are to some extent the result of fires intentionally set by humans. Grasses have several ecological attributes that enable them to survive grazing, drought, fire and cold. For one, they can reproduce by spreading underground. With their extensive root systems, much of the plant is underground and protected from herbivores, fire, and cold. Since the grass does not produce a lot of long-lived biomass, many of the nutrients are held in the soil. This makes the land good for agriculture. There are several types of grasslands, each found in a different climate:

Prairie - temperate grassland

Tundra - Arctic, high mountain grassland

Savanna - tropical grassland

Plant Nutrients

Materials needed for photosynthesis

Water - source of hydrogen

CO2 - source of carbon

Nitrogen - needed for amino acids

Phosphorous - used in ATP, DNA, cell membranes

Magnesium - used in chlorophyll

Sources of minerals


Mineral availability - affected by soil

Epiphytes - getting by without soil



preparing soil
  1. slash-and-burn
  2. machinery
  3. soil erosion
  4. use of fossil fuels
  5. soil compaction
  1. efficient
  2. susceptible to disease, pests
  1. replace lost nutrients
  2. expense
  3. eutrophication
  1. attempt to deal with pest problems caused by monoculture

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Grasslands- Prairie - Tundra - Savanna


Sources of Minerals - Fertilizers - Mineral Availability - Epiphytes - Agriculture

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