Expert: Walter Hintz - 1/9/2007

Question
how can i carry out a quantative survey of the plant speciesin a local habitat


Answer
 Hi fifi
The first thing you must do is determine the total area involved. Measure the area of study in square meters.  Lets assume that the habitat of study is 100 x 100 meters which would be 10,000 square meters.  I suspect that you are to count all of the herbaceous an woody plants in that area. Now you have to use smaller areas called quadrats and count the species in the quadrat.  Each quadrat is selected at random.  Begin by counting the herbaceous plants in the area One square meter would work.  Take a stick and throw it over your shoulder.  Where it lands take a meter stick and measure 1 square meter.  Count the plants in the square meter.  Do this ten times. Lets say you are surveying may apples and oak seedlings and in ten quadrats you count 85 may apples. and 12 oak seedlings This averages out to 8.5 plants and 1.2 oaks per square meter.  Your total area is 10,000 square meters so the total number of may apples in the area is 8.5 x 10,000 or 8500 may apples and 1200 0aks.
If you are counting trees obviously a 1 sq meter quadrat will not work so you need a bigger quadrat.  For large tree it may be possible to just count each species of tree in the area and mark them.
 The important thing is to select quadrats at random.  You may find one quadrat with 15 plants and another with 5 but if you randomize you will get an accurate number.
 If this does not explain it get back to me.