EMS-Natural ecosystems and human activity, page no 198

What are quadrats, transects and pitfall traps:

• Quadrats: A quadrat is a frame used in ecology, geography, and biology to isolate a standard unit of area for study of the distribution of an item over a large area. Quadrats typically occupy an area of 0.25m2 and are traditionally square, but modern quadrats can be rectangular, circular, or irregular.

• Transects: A transect is a straight line that cuts through a natural landscape so that standardized observations and measurements can be made.

• Pitfall traps: A pitfall trap is a simple device used to catch small animals - particularly insects and other invertebrates - that spend most of their time on the ground. In its most basic form, it consists of a container buried so that its top is level with the surface of the ground. Any creatures that wander nearby may fall in.

The advantages of quadrats:

• Quick.

• Inexpensive.

• Portable

  The disadvantages of quadrats:

• Not always very accurate.

• Unless many quadrats are placed, the sample can be unintentionally biased.

The advantages of transects:

• Quick.

• Inexpensive.

• Portable.

The disadvantages of transects:

• Often used in inappropriate situations, so care must be taken when deciding whether or not to use a transect.

  
  

  The advantages of pit falls traps:

• Inexpensive.

• Easy to set up and use.

  The disadvantages of pit fall traps:

• May oversample or under sample.

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