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In this activity, we will study the organisms and environment along a gradient from the edge of a marsh to the top of the hill.
- Evaluate small scale gradients in biological and environmental conditions along a transect.
- Create graphical summaries of the findings
- Enter data into class database [link to google doc]
The UCI Arboretum map of UCI Arboretum
- GPS device
- TDR probe for measuring soil moisture
- Meter stick
- LICOR LI-800 gashound, with chamber for measuring soil respiration, 12V battery, and pump
- Clippers for harvesting aboveground plant biomass
- Trowel for harvesting roots
- Water bath for rinsing roots
- Portable scale for measuring plant biomass
Class will survey a 100m transect at 20m intervals. Five groups of four will take turns conducting the following measurements:
- Soil CO2 efflux
- Aboveground plant biomass
- Root biomass
- Soil Moisture and insect biomass
- Plant diversity
- Measure soil moisture with TDR probe
- Measure soil temperature using thermometer
- take a soil core and place it in a bin
- mix the core well
- pairs of students should place a portion of the soil and count the number insects in each group
- after counting an insect, place it in a pre-weighed tube
- weigh tubes with insects from each group and record
- subtract original tube weight from weight of tube plus insects, this is the insect biomass
- Clip plants along a 150 cm by 10 cm strip at ground level.
- weigh plants and record mass
- Create a spreadsheet based on this template:
- Fill in data for each sample site
- Calculate biomass of plants and insects in units of g or mg per m2
Graph plant and insect biomass, soil temperature, and soil moisture on a chart. Here is an example; example transect results
- Look at your graph and describe the patterns that you see
- Are plant and insect biomass correlated along the gradient?
- How are soil temperature and soil moisture related to plant and insect biomass?
- What other patterns did you see?
- Why do you think that these patterns exist?
Write a one paragraph summary of your analysis.