Chapter 4: Kinds of Ecosystems

Section 4.2: Grasslands, Chaparral, Deserts,

and Tundra

• Forests are replaced by grasslands, savannas, and chaparral in climates where there is less rainfall.

• These are replaced by deserts (in warm areas) and tundra (in cold areas) when there is even less rainfall.

• As precipitation decreases, the diversity of species also decreases.

Temperate Grasslands:

*Temperate grasslands – biomes occurring in semi-arid interiors of continents.

Temperate Grasslands:

• The temperate grasslands are also called prairies, steppes, and pampas, depending on where they are located.

Temperate Grasslands:

• Central United States – prairies

• Russia and Ukraine – steppes

• South America - pampas

Temperate Grasslands:

• Grasslands have the most fertile soil of any biome.

Temperate Grasslands:• This is why most of them have been

replaced with crops of corn, soybeans, and wheat.

Temperate Grasslands:

• Grasslands used to cover 42% of the land area of Earth, but they now cover only 12%.

Temperate Grasslands:• There is too little rainfall

for many trees to grow.

• Often mountain ranges maintain the grasslands because they stop the rainfall.

Temperate Grasslands:• Short-grass prairies occur just east of the

mountains.

• Rain increases farther east, so there are taller grasses and some shrubs.

Temperate Grasslands:• Heavy rain is rare

and the temperature can be extremely hot, so fires are common.

Temperate Grasslands:

• Prairie grasses are perennials.

• They have dense root systems that survive winter temperatures, drought, and fires.

Temperate Grasslands:• Few trees can survive the

drought, fire, and strong winds.

Temperate Grasslands:• Grazing animals have large, flat back

teeth for chewing the tough grass.

• Examples: antelope, buffalo, deer.

Temperate Grasslands:

• They have thick fur coats for winter and shed them in the spring.

Temperate Grasslands:

• Other animals live in underground burrows to protect themselves from fire, weather, and predators (such as wolves).

Temperate Grasslands:• Examples of

burrowing animals:–Badgers

–Prairie dogs

–Some owls

Temperate Grasslands:• Cultivation and overgrazing have

changed the grasslands.

Temperate Grasslands:

• The grain crops and overgrazed grasses can’t hold the soil in place and erosion then occurs.

Field Investigation:• Now that we have discussed the temperate

grassland ecosystem and reviewed, we will use the procedure in your lab manual to conduct a thorough field investigation of a nearby grassland.

• With your lab partner, read through the investigation procedure and prepare to discuss it with the class.

Field Investigation:

• Class Discussion Points:– Abiotic factors: measuring temperature,

atmospheric pressure, weather conditions, moisture, elevation, slope of the land, soil sampling, etc.

– Biotic factors: animal life, insect collections, plant collections,

Plant Collections and

Herbarium Preparation

Plant Collections are samples of plants that can be:

1.Dried and mounted on paper (herbarium specimens)

2.Liquid preserved

3.Kept alive and grown in a greenhouse or garden

Why do we collect plants?• To use as a resource for plant taxonomic studies.

(a catalogue of plants)

• To provide a reference collection of specimens which can be used to identify plant species.

• To provide information about the plant in its native habitat.

• To study global changes in species or climate.

How can we:1. Obtain specific plants for a research study?• Use label information from herbarium specimens to

find their locations.

• Use maps to find likely habitats.

2. Do a complete inventory of plants for a field study?• Collect and identify every plant in a region during

different seasons and/or different years.

What should we collect?

• We should not collect rare, endangered, or threatened species. We must know ahead of time which these are!

• When we collect, we use the “1 to 20” rule:– For every herb we collect, we should make sure there are at

least 20 more in the population.

– For every branch of a shrub or tree we collect, we should make sure there are at least 20 more.

How do we collect our plants?

Herbs: We must dig up at least one entire plant to show its root or rootstock.

Shrubs, trees, vines: We should collect one representative branch that shows the vegetative and reproductive parts of the plant.

• We will use a plant press to flatten and dry them.

• We will sandwich each specimen between pieces of newspaper and cardboard, cutting or folding them to fit and to prevent too much overlap.

How do we preserve our specimens?

How do we preserve our specimens?

• At least one leaf should be up and one leaf down.

• We next stack them on top of each other inside the press and tighten the straps.

• We will leave them to dry, checking them each 2 – 3 days.

How do we make our herbarium?

1. When our plant specimens are dry, we will glue each of them to a separate sheet of cardstock.

2. We will attach an identification label to the cardstock.

3. We will store our collection in a file and add to it with each field investigation.