Transcript Temperate Grasslands - SETI-2-2013

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 semiarid 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.
How do we preserve our specimens?
•
•
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?
•
•
•
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.