Assessing Plant Diversity

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Assessing Plant Diversity

• Quadrat Investigation

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Getting to know the forest

• Forests are large stands of trees, shrubs, and
  herbaceous plants
• A quadrat is a designated area in which plant
  diversity is assessed. This makes the task of
  identifying all the plants more manageable
• Random sites are chosen
• Distances from the center of the site are
  measured and marked with flagging in each
  direction

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Quadrat
North
NE quadrat
NW quadrat
10 meters 30 feet
West
East
SW quadrat
SE quadrat
South
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Layers of the Forest
Canopy
Understory
Herbaceous plants
Leaf Litter
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Measuring Canopy trees

• This gives us a measure of the age class of the
  trees
• Identify the species
• Collect leaves, fruit, pieces of bark (if
  possible)
• Measure the width of the tree
• Diameter breast height (DBH)

DBH
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Shrubs and Bushes

• Defined as woody plants that have many stems
• Identify the species
• Collect leaves, flowers and /or fruit.
• Measure DBH if greater than 2.5 cm

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Consumers and Decomposers

• Leaf Litter

• Soil

• Take the soil temperature in the woods
• Collect some soil in a baggie
• Take it back to the lab to test the
• pH
• Water content
• Organic matter
• Phosphorous
• Nitrogen
• Potassium

• Collect some in a baggie
• Examine with a dissecting microscope back in the
  lab
• Look for insects, fungi, worms
• Expose an agar plate to the air at ground level
  and in the air to catch mold spores and
  bacteria.

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Species Diversity

• Species richness The number of different species
  in the quadrat.
• Species abundance The of each species in the
  whole quadrat.

of individuals of a particular species total
of individuals of all species
100
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Calculating Species Diversity

• N0 of different species present
• X0 total of trees counted
• Species Abundance Xi / X0
• Dominance Index ( C ) ? Xi / X0 add up all
  of the species abundance numbers
• Diversity Index (D) 1 - C

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Conclusion Questions

• Woody Stem Diversity
• Collect the data from the other groups in the
  lab.
• Make a list of all the tree species that were
  found. Include both the common and scientific
  names.
• Using the class data, calculate the species
  richness and species abundance for the entire
  quadrat.
• Calculate species diversity

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Conclusion Questions

• Summarize your soil and leaf litter data in a
  paragraph. List the organisms found and whether
  they are consumers or decomposers.
• Summarize any other animals that were found.
  Where do they belong in the food chain of the
  forest?