1.3.9

Ecological Sampling

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Ecological Sampling - Quadrats

Ecologists may have to sample large areas. Ecologist's reports are important. Ecologist's reports may lead to conclusions that can make the area more sustainable and help to conserve it.

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Ecological sampling

  • Sampling by ecologists may take place over very large areas.
  • For example, an ecologist may want to sample a plant population.
    • It would take too long to count all the plants.
    • Some of the plants might be missed.
    • Counting all the plants would be like counting the blades of grass on your school field.
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Sampling large areas

  • Sampling large areas would take too long and could be very expensive.
    • It is important to create a report that is accurate and represents the sampled area.
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Quadrats

  • Quadrats are a good tool to sample organisms in the field.
    • Quadrats are used to study sessile organisms.
    • Sessile organisms do not move.
    • Plants are sessile organisms.
  • Animals are harder to sample because they move.
  • Quadrats are normally a 1x1 square frame with netting inside.
    • Netting turns the frame into a grid.
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Measuring with quadrats

  • Quadrats can be used to measure biodiversity in terms of:
    • The population size of a species
    • Species richness – how many of each species are present in a given area
    • The distribution of a species – how and where a species is present in a habitat

Ecological Sampling

There are many kinds of sampling. Random sampling and line transects are forms of sampling.

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Random sampling

  • The sampling area needs to be mapped out for random sampling.
    • The area should be mapped out with coordinates.
    • Coordinates should then be chosen at random.
  • Coordinate numbers should be chosen with a random number generator.
    • This prevents bias.
    • Bias can lead you to select areas with high or low organism numbers.
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Random sampling results

  • Once you have placed your quadrat, count the number of species present in the quadrat grid.
  • You can also record the % coverage of the species.
    • The % coverage is sometimes difficult to calculate.
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ACFOR

  • A range scale can be used instead of % coverage sums.
    • ACFOR is a range scale.
  • ACFOR stands for:
    • A – Abundant 90-100%
    • C – Common – 50 – 90%
    • F – Frequent – 20 -50%
    • O – Occasional 5 – 20%
    • R – Rare – up to 5%
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Line transect

  • Line transect sampling uses a quadrat.
    • Instead of random sampling, the quadrat is placed at regular intervals.
    • The number of species can be recorded at regular intervals.

Jump to other topics

1Biology

1.1Cells, Tissues & Organs

1.2Reproduction & Variation

1.3Ecological Relationships & Classification

1.4Digestion & Nutrition

1.5Plants & Photosynthesis

1.6Biological Systems & Processes

2Chemistry

2.1Particles

2.2Chemical Reactions

2.3Atoms, Elements, Compounds

2.4The Periodic Table

2.5Materials & the Earth

2.6Reactivity

2.7Energetics

2.8Properties of Materials

3Physics

3.1Energy

3.2Forces & Motion

3.3Waves

3.4Electricity & Magnetism

3.5Matter

3.6Space Physics

4Thinking Scientifically

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