Physical Gathering Techniques

Question 1

How do you conduct a vegetation analysis?

Answer 1

1. Decide a site and sampling method.
2. If systematic - lay tape measure along transect, noting aspect/direction, assigning sites along regular intervals.
3. If random - divide a base map into grids and number them. Use a random number generator to assign sites.
4. Throw the quadrat in the appropriate site.
5. Carefully identify each plant type, height and abundance.
6. Record results.
7. Note conditions e.g. weather, noticeable disturbance etc.

Question 2

What are the advantages of a vegetation analysis?

Answer 2

Advantages:

1. Relatively easy to conduct without requiring complicated equipment, making it easier to include in a larger study.
2. Quadrat sampling is effective without needing to remove or damage vegetation.

Question 3

What are the disadvantages of vegetation analysis?

Answer 3

Disadvantages:

1. Identification can be difficult for non-specialists which can lead to inaccurate data.
2. Quadrat spacing can influence or skew results (large spacing inflates coverage data). This requires percentage coverage to be recorded to avoid this.
3. Time of year has a large impact. Best carried out in Spring/Summer where plants are more visible or in growth.

Question 4

How do you conduct a slope analysis?

Answer 4

1. Locate the slope and create a transect to follow and note the bearing using a compass.
2. Place the first ranging pole at the bottom of the slope. This is point A.
3. Have a second person walk along the slope until there is a change in gradient. Place the second ranging pole. This is point B.
4. Measure the distance between A and B.
5. Place the clinometer at eye level next to the ranging pole. Pull the trigger and angle the clinometer until it is pointing at the same spot on the other ranging pole. Release the trigger without moving and record the angle of the slope.
6. Repeat until the end of the transect.
7. Results can be used to create a cross section for further analysis.

Question 5

What are the disadvantages of slope analysis?

Answer 5

Disadvantages:

1. Clinometers are difficult to use accurately which could provide false readings.
2. Can be difficult to read from ranging poles as they can move in shallow soil and depth can impact the accuracy of the height of the pole.
3. Access can be an issue depending on land use or ground cover.
4. Deciding on where to place ranging poles can be difficult, relying on investigators own decisions.

Question 6

How do you conduct a pebble analysis?

Answer 6

1. Locate sample site. Create a transect or use a quadrat for random sampling.
2. Reach down with index finger and select first pebble it touches.
3. Use callipers to measure axis a, b, c of the pebble. Calculate average length to find the mean pebble size.
4. Compare with the Cailleux Scale and note angularity.
5. Record these measurements.
6. Note additional information such as grain size, land use, river height/speed.
7. Repeat at each site.

Question 7

What are the advantages of pebble analysis?

Answer 7

Advantages:

1. Use of visual charts is helpful however can add subjectivity based on pictures used.

Question 8

What are the disadvantages of pebble analysis?

Answer 8

Disadvantages:

1. Cailleux scale has subjectivity as data is based on opinions.
2. Many factors can influence results e.g. storms, walkers, wildlife can all disturb sediment.
3. Access and risk are problems as working near rivers can be dangerous which limits available sites.

Question 9

How do you measure a beach profile?

Answer 9

1. Create a transect to follow and note the bearing using a compass.
2. Place a ranging pole at the highest point the waves reach. This is point A.
3. Place a ranging pole at the next point the slope changes. This is point B.
4. Measure the distance between A and B.
5. Place the clinometer at eye level next to the ranging pole. Pull the trigger and angle the clinometer until it is pointing at the same spot on the other ranging pole. Release the trigger without moving and record the angle of the slope.
6. Repeat until the end of the transect.
7. Results can be used to create a cross section for further analysis.

Question 10

What are the disadvantages of measuring a beach profile?

Answer 10

Disadvantages:

1. Ranging poles can easily sink/move in sand reducing accuracy.
2. User error is common when using a clinometer which reduces accuracy.
3. Depending on the beach this could be very time consuming if there are multiple sections or metres of beach to measure.
4. Safety is a major consideration and can impede measuring.

Question 11

How do you conduct a microclimate analysis?

Answer 11

1. Decide on sites and sampling method, usually along a transect to investigate how weather changes over distance.
2. At each site measure:
   - temperature using a thermometer
   - wind speed using an anemometer
   - wind direction using a wind vane
   - humidity using a hygrometer
   - precipitation using a rain gauge (usually over a 24 hour period)
   - aspect using a compass
3. Record the results and the time the measurements were taken

Question 12

What are the advantages of microclimate analysis?

Answer 12

Advantages:

1. Can be used to investigate a wide variety of topics.
2. Large quantities of data can be collected using basic versions of equipment or judgements. Although less accurate.

Question 13

What are the disadvantages of microclimate analysis?

Answer 13

Disadvantages:

1. Uses lots of complicated equipment which all function differently, requiring a lot of learning to conduct.
2. Difficult to ensure data is collected in an accurate time frame e.g. checking rain gauges at the same time.
3. Analogue instruments can be inaccurate. Digital instruments need to be charged and calibrated to function accurately.
4. Many small variables can influence results making accurate analysis difficult.

Question 14

How do you conduct a soil analysis?

Answer 14

1. Decide sites and sampling method.
2. Measure pH – use either an electronic meter or the test tube and indicator solution method, where a soil sample is mixed with barium sulphate, pure water and pH indicator solution, and compared to a pH chart.
3. Measure temperature and moisture — use temperature and moisture probes. Alternatively, take a soil sample in a sealed plastic bag and find the moisture content by weighing, drying out in an oven, and then re-weighing.
4. Measure soil profile — dig a section out of the soil so that the different horizons can be seen. Write descriptions of the structure, texture, organic content, colour and depth of each horizon

Question 15

What are the advantages of soil analysis?

Answer 15

Advantages:

1. Calibrated meters are accurate and reliable.
2. The equipment is relatively easy to use and can be used by non-specialists.

Question 16

What are the disadvantages of soil analysis?

Answer 16

Disadvantages:

1. The delay of removing soil and then measuring in the lab can lead to inaccuracy in the data.
2. Weather and external factors can greatly influence soil.

Question 17

How do you conduct a stream analysis?

Answer 17

1. Measure river depth — use a meter ruler or ranging pole and take measurements at regular 30cm to 50cm intervals (depending on the channel size). Can be used to build cross section graphs.
2. Measure river width — stretch a tape measure taut across the river at 90 degrees to the channel. The start and finish points of the tape will depend on whether the river is being investigated at its existing level or in high spate. Measuring at the vegetation line can show this variation.
3. Measure wetted perimeter — measure the wetted perimeter by stretching a heavy chain, rope or measure tape across the river bed from one bank to the other. Can be used to establish discharge levels from cross section area graphs
4. Measure flow rate — either use a flow meter or a floating object such as an orange to record the time taken for the object to travel over a set distance: speed equals distance over time

Question 18

What are the advantages of stream analysis?

Answer 18

Advantages:

1. All techniques can be carried out with minimal equipment.

Question 19

What are the disadvantages of stream analysis?

Answer 19

Disadvantages:

1. Safety is a huge concern working in water.
2. Using the tape measure over such large areas can be inaccurate or difficult to manoeuvre.
3. Using the orange for flow rate can lead to mistakes in calculations.
4. There can be many variations depending on season/flow etc.