Additional Field Problems

 

Community Similarity, Canopy Density, Population Density, Wildlife Enhancement

 

1.      Community Similarity

If you are studying more than one 20 meter by 20 meter quadrant, you may want to quantify the “similarity” between quadrants. Community comparisons may be made from a number of different types of samples taken (bird or insect species present or absent). Using the index of similarity known as the Coefficient of Community (C), you may calculate a comparison. Using this coefficient the index range is from 0 (no overlap) to 1 (identical communities in that respect).

 

Example:

 

One quadrant may be 95% oak and 5% hickory while a second quadrant may be 95% hickory and 5% oak. The index is calculated as follows:

 

 

 

 

Where:                 a = sum of the scores for Community A

                              b = sum of scores for Community B

                              W = Sum of the lower scores for each species

 

 

 

 

 

 

 

 

 

Keep in mind that you may compare tree frequency, density, and dominance values as well as biomass of leaf litter. Estimations of populations of insects may also be considered (Field Problem 3), canopy density (Field Problem 2), or even bird sightings.

 

2.      Canopy Density

You may construct a simple and inexpensive “Densitometer” by using a tube (pvc piping or paper tissue roll tube), monofilament string and a nut for the weight.

In your 20 meter by 20 meter quadrant, students will walk the two diagonals connecting opposite corners of their quadrant and measure whether or not they see leaf cover (+) or sky (-) each meter.

The canopy density id computed by dividing the total number of +’s by the total number of sightings.

Example:

A student walks the two diagonal and marks 15 +’s for 20 sightings. The canopy density of that plot would be:

 

 

 

        Obviously, canopy density (leaf cover) varies from season to season in deciduous forests. As an extension, have students repeat the above at various times of the year for comparisons and applications to other organism activity (winter diapause and overwintering insects in leaf litter, spring flowers and understory plant phenology.

 

!!!INSERT ILLUSTRATIONS!!!

 

3.      Population Estimations: Capture/Release Method


Students may estimate the population size of invertebrates by using the Capture/Release Method.

 

Students make a sweep through their quadrant capturing an invertebrate species and marking all with a color marker (M1). These organisms are released back into the quadrant. The next day students sweep the quadrant for the same species and note the number recaptured with the color marker (M2) versus the TOTAL number (P2) captured the second day.

 

Using the following calculation students solve for P1 (total population):




 

 

 

4.      Wildlife Enhancement Option & “Featured Creature” Report

 

You may want to extend this project by asking your students how they may make a difference with respect to global diversity. Wildlife managers often develop a plan to enhance habitat to assist a species recover it’s population in an area it once frequented. Certainly this management policy is intended to assist native species regain their populations in an area that has been disturbed and not introduce exotic species into that same area.

 

Ask students to research a species and its’ needs (niche and habitat needs) and make recommendations for your quadrant(s) that would encourage that particular species. If students are wiling to put the plan into action, they should FIRST present their plan to a local conservation committee or state wildlife agency for approval.

 

Whether students are able to put the plan into action or not, the following activity and report sheet may be used to assess student knowledge and skills concerning habitat and wildlife.


State Cooperative Extension Services as well as conservation organizations do have resources available for you to use for this aspect of your curriculum and HabitatNet project.

 

The National Wildlife Federation provides a kit for a Backyard Wildlife Habitat Program for a nominal fee that includes “certification” for your project. The kit includes examples of plantings that attract wildlife and suggestions for improving wildlife.

 

You may contact them at:

 

National Wildlife Federation

1412 16th Street, NW

Washington, DC 20036-2266