Quadrats

• A quadrat is usually a square frame of metal, wood or plastic, of known size.
• An area where organisms must be counted is demarcated and the surface area determined
• The quadrat is placed on the ground in the demarcated area and the organisms concerned are counted inside the metal frame; this is the number of individuals per unit area
• This process is repeated a few times in different areas of the demarcated area by placing the quadrat randomly on the ground
• The average number of individuals per quadrat is calculated
• The total number of individuals in the population is determined using the following formula:

  Population size= average number of individuals per quadrat x surface area of the area ÷ surface area of the quadrat
• The reliability of this technique depends on the exact number of organisms in each quadrat must be known
• The reliability of this technique depends on the surface area of the quadrat must be known
• The reliability of this technique depends on the surface area of the demarcated area must be known
• The reliability of this technique depends on the quadrat must be placed randomly in the demarcated area