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What is found on the school lawn?
Researchers want to know what plants grow in a habitat.
They cannot count every plant. So, they count the plants in a random
sample of square meters called quadrats. This data is summarized and
used to describe the total plant population. The more quadrats sampled,
the more accurate the description
Because researchers want to compare data, they
must collect the quadrat data according to standard procedures. You
will be working
in a research team of three to four students to develop your skills
taking quadrat data. Read the procedure and decide who will do steps 3
and 4 below.
School Lawn Quadrat Activity Procedure
- You will need:
- Quadrat tool or four (4)
meter
sticks
- Data sheets
- Metric rulers
- Pencils
- Colored pencils or crayons for color coding
- Mark off a square meter of school
lawn using meter sticks or a quadrat tool.
- Some students will record your
data beginning with the grid sheet. Draw the location of all the
materials you find in your quadrat. Use a color or pattern
to show what each object is and make a key noting the object and its
color or pattern.
- Other students will count how
many of each object there is in the quadrat.
HINT: If you come across something that is difficult to count, like
grass or rocks, measure a smaller square of it with a ruler. Use a
square centimeter for really small things. Count the number of objects
in the
small square and multiply that number by the number of small
squares
that make up the bigger one. This is called sampling!
- Record the
percent of the area covered by each material.
From the grid sheet, count the number of squares that each object
occupies. Remember, each square is equal to 1% coverage. Include the
total area each covers. If the total area a plant takes up is less than
one square, record it as 0.
Click to see discussion questions for this
activities
School Lawn Quadrat Study - Data Sheet
Color or Shade in the areas on the quadrat grid below that contain
that object's color or pattern from the code below.
Remember that each square will equal 1% of the quadrat. Sum up
all the squares and parts of squares to find the total percent covered
by that species. That percentage should then be placed on the Lawn
Quadrat Data
sheet.
School Lawn Quadrat Study - Data Sheet
Quadrat Data Table
Remember the total of all the percentages should equal 100!
* DISCUSSION
QUESTIONS:
1. When you do a study
like this at the Fermilab prairie, students will enter their data into
a
computer and that computer will calculate something called an
Importance
Value. This value tells us how important a plant is to the area. Since
you
do not have this computer and software at your school, we will try a
simple
version for this. Have students look at the number found and % cover
for
their plants. Ask them to determine which plant they think is the
dominant
or most important plant in their study.
2. Species diversity
is very important to the stability of an ecosystem. If many different
species are present, then the loss of one or two will probably not have
a great effect. But if species diversity is low, the loss of one or two
could have a major impact. In the original prairie of Illinois species
diversity was probably twenty-five different species per square meter.
Calculate the species diversity for your quadrat by counting the number
of different types of plants you
found. Species diversity = _____per square meter. How does the species
diversity of your school lawn compare to that of the prairie? Which
ecosystem would be more stable?
3. How many of each
type of plant are on your entire school grounds? How could you figure
this out? DO IT!
4. Scientists do not
base their calculations on just one quadrat as you just did. Instead
they
will use the data from many quadrats. Why do you think they do this?