ECOLOGY FIELD LAB

Ecology is the study of the interactions among organisms and their environment. This lab exercise is designed to introduce the student to some of the ways the many interactions can be measured and studied. The environment has biotic (living) and abiotic (nonliving) factors. You will collect data concerning both, and look for relationships. The collection and analysis of each data set will constitute one lab exercise. Each lab exercise requires a large investment of time and work. Exercises I - III can be completed with the use of materials normally found around the home. Exercises IV - VII require specialized equipment. For each exercise, you will collect specific data, organize and display the data in the form of tables and graphs, compare the results to known results, and draw conclusions based upon your data.

The data sets to be collected are:
  •    I.
  •   II.
  •  III.
  •  IV.
  •   V.
  •  VI.
  • VII.
  Trees
  Ground Cover and Shrubs
  Macroscopic Animals
  Microscopic Animals
  Protists, Aquatic Plants and Fungi
  Monera
  Abiotic Components
  Tree Keys

   ( Birds )
 
  Protozoa Key   Floating Plants
 


Start by selecting an area to be studied. It can be anywhere-from an urban parking lot to a forest. Some areas will be more difficult to study than others. You have to be able to get there at all times, so don't pick a place in the remote mountains unless you plan to stay there for a while. Ideally, you will be assigned an area. Once the area has been decided on, mark off a 20 X 20 meter square quadrat, this will be the sampling area. You can't measure everything, so you must take a representative sample of the whole area. The quadrat is your representative sample and all data will come from within the quadrat.

  • I.  TREES

Collect The Data

The trees are probably the easiest to identify and measure.

The first step is to make a map of you quadrat. The map must be to scale. Include all trees over 10 cm in diameter and any prominent features of the area. If you have a cluster of trees, with no one tree being over 10 cm, create a symbol for the cluster. If the quadrat has a slope, gully, stream, fallen tree, large rock, etc., note it on the map.

Making the Map

Although the map has to be to scale, it doesn't have to be perfect. You can measure your stride and pace off the position of each tree and object on the map. Graphing paper may be of help in keeping things lined up and to scale. Color , although not necessary, can add another dimension to the map, making it easier to read. Be sure you show the compass direction to North. Also, you must supply a description of the location of the quadrat. In other words, how do I get there?. Something like, "Tree 1 is 52 meters due North of the North East corner of the PRC-JSRCC cooling tower.




Organize Raw Data

Second, create a table for the collection of raw data in which you list the tree species, height, circumference and diameter ( diameter = circum./ 3.14)for each tree in the quadrat. Assign a number to each tree on your map which corresponds to the number of the tree on the table.

tree #

tree (species)

height (m)

circumference (m)

diameter (m)

1

            

2

            

3

            

4

            



Tree Measurements and Identification

Tree diameters are easy to measure. The standard method is to measure at breast height. Use a tape measure. Measure and record the circumferance. Divide the circumferance by pi (3.14) to get the diameter.


Tree height is a little more difficult. Probably the easiest method is the "ruler at arms length" method. Stand a meter stick at the base of a tree. Walk far enough away from the tree so that you can easily see the top and bottom of the tree. Hold a meter stick at arms length from you and measure how tall the meter stick at the base of the tree appears to be. Next, while still holding the meter stick at arms length, measure how tall the tree appears to be. Divide the apparent height of the tree by the apparent height of the base-of tree meter stick and you will have the real height of the tree in meters.



Identify the Trees

In order to identify the trees, you will need to have a leaf sample and use one of the Tree Keys. The terms you must be familiar with are:
alternate opposite whorled
lobed toothed
node
petiole
leaflets
leaf scar
lenticel
simple compound double
compound		  
needles
broad leaf
deciduous
evergreen
 
 		 .

You are now ready to organize the data, compare it to known information, such as the Successional Tendencies and draw conclusion about your area.

Create a table which list the tree species, number of each species, average height, and total cross sectional area. The total cross sectional area is found by adding the cross section area of each tree of a species to get the total for the species. For example, if you have four northern red oaks (Quercus rubra), use the diameter to calculate the area for each, then add the areas to get the total area. The dominant tree species will be the species with the largest total cross section area.

Compare this information with the information presented in the resources provided.

What conclusions can be drawn? Age of area; stage of succession, stability; usefulness for building, for crops, for a park. Use your data to support your conclusions-in other words, how do you know?