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1.  What you can do
2.  Water
3.  Ecology
4.  Amphibians
5.  Environmental Issues
6.  Keystone species
7.  Get Wet!-
     Field Study Ideas

8.  The Zoo Experience
9.  Frogs & Friends
10. Case Studies
11. Resources
12. Glossary

Wetland Curriculum Resource
Unit 5. Environmental Issues -

5.6 SILENCE OF THE CONTAMS                                         (Level: 7 : 10 acad : 10 appl : 11 acad : 11 appl :: Pollution Indicators)

Purpose: To observe the presence and populations of organisms in a wetland, and realize their significance as indicators of environmental contamination.

What You Need: data sheet :: pencil :: binoculars :: field guides

What You Do:

  1. Visit a local wetland. When at the wetland, it is important to stay as quiet as possible as it will definitely increase your chances of seeing wildlife. Try to ensure the least amount of impact is left on the surroundings.
  2. Observe and record estimates of the different life forms that exist in the wetland in this pop-up table (available here if you cannot view pop-up windows). This can be based on visual sightings, listening for calls, browsed plants, tracks, and droppings. Check off the numbers for different species of organisms, and the relative numbers of any one particular species. Then, determine visually if the four required needs for good habitat are present. This exercise requires careful inspection, and sufficient time should be allotted to complete a thorough investigation.
  3. From your data collected, formulate an opinion as to whether or not the wildlife present may be under environmental stresses, based on the organisms that are present or absent.
  4. Conduct the same test on another wetland to determine its environmental quality.


  1. Define indicator organism. Identify 3 indicator organisms that can be found in a wetland?
  2. Can conclusions be drawn from relying solely upon the biological data regarding the nature and the degree of contaminants in an aquatic ecosystem? Why or why not?
  3. Bioaccumulation is a process where contaminants are consumed and retained in an organism. What level of the food chain does biomagnification have its greatest effect on? Why?
  4. What factors are contributing to the environmental quality of this wetland?
  5. Explain why amphibians are such good monitors of environmental quality.


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