Target Range (Missoula, MT) Insectary

under construction 10-05
AmeriCorps installing 4 Insectory Plots at Target Range School:

Target Range School Knapweed Biocontrol Study

Name________________________           Date________________________

Teacher       Burreson      Clouse                    Assisted by (initials)____________

Soil Temperature ______ºF      Soil Sample                    Plot ID____________

Knapweed Plant Count



(1-5 leaves)


(>6 leaves, no flowerhead)


(flowerhead or stalk)

Number of plants




Knapweed Basal Collar Measurement (adult plants only)


Plant 1

Plant 2

Plant 3

Diameter (mm)




Percent Cover by Plant Type





























Other Observations:




Questions about activity:




Suggestions for future investigations:

Notes for Data Collection Supervisors:

Within our study area there are 4 sampling grids: 2 insectory grids and 2 control grids.  Each grid is 4 meters x 3 meters in size, and there are a total of 48 total plots to be sampled.  This sampling design will provide experimental replication and allow for more rigorous statistical analysis.  Although the study area is small, there are two distinct vegetation zones within it: one that is virtually a knapweed monoculture (see IN and CN sampling grids) and one that is composed of knapweed and other native and non-native grasses and forbs (see IS and CS sampling grids).  This sampling design will allow us to explore several types of questions concerning biocontrol of invasive plants.  Consider the following:

  1. Effects of biocontrol on knapweed (control grids vs. insectory grids)
  2. Influence of plant community diversity on biocontrol (southern vs. northern grids)
  3. Can elementary students be used to collect accurate data (within-grid data analysis)




As student approaches:

  1. Direct student to a sampling grid (IS, CS, CN, IN) and plot (IS2, CN4, etc.). 
  2. Place PVC sampling frame around plot, using flags as guides
  3. Record Plot ID on data sheet(C**for control plots; I** for insectory plots) and pull the ID pinflag from the center of the plot
  4. Record student’s name, teacher, and your initials
  5. Have student insert soil thermometer into the approximate center of the plot at about 3” depth – after the student has collected all other data, record soil temperature on the data sheet.


Soil Sampling:

We will be collecting soil samples from each plot to determine soil moisture, pH, and fungal community associations.  For each student and plot:

  1. Collect a soil core from each quadrant in the plot (from bare ground where possible)
  2. Seal all four cores into a single Ziplock bag
  3. Write the Plot ID (IN2, CS4, etc), date, and your initials on the bag

Knapweed Plant Count:

  1. Show student reference samples for knapweed seedling, young, and adult plants
    1. Seedling = 1-5 leaves
    2. Juvenile = 6 leaves to initiation of flower head
    3. Adult = Initiation of flower head to maturity

(from Jacobs and Sheley, J. Range Manage. 51(6), 1998)

  1. Supervise plant count (you can help students keep track of counts by suggesting that they count plants from top to bottom or left to right in plots, and by using the ¼ plot templates to focus on specific areas)
  2. Record counts in appropriate table

Knapweed Basal Collar Measurement:

  1. Show student where to measure the basal collar
  2. Instruct student to randomly choose three ADULT plants to measure
  3. Record measurements in appropriate table

Percent Cover of Plants in Plot:

Students will be collecting % cover of knapweed, grasses, and forbs in each plot.  Here are some guidelines for calculating percent cover for each plant type:

  1. A plant covering a 10cm x 10cm area occupies approximately 1% of the total area in the plot, a 30cm2 plant occupies 10% of the plot, and a 50cm2 plant occupies 25% of the plot. 
  2. Use the reference squares to calculate total % cover of each plant type (10cm2 = 1%, 30cm2 = 10%, and 50cm2 = 25%)

***Note: Total percentage across vegetation types should not add up to 100%, unless there is no bare ground showing in the sampling plot!!!

As student leaves:

Direct her/him to select a prize from the box! HOME     Teacher Weed Curriculum