teaching notes 4 - organising mini-beast sampling trips
Ref: T04

Notes for group leaders and students

Organising the field trip

Selecting a suitable river or stream for habitat sampling should be a joint activity between the teacher or group leader and pupils. The chosen site should be pinpointed on a map and a grid reference taken before the visit. The river, place name and nearest town must be recorded and permission must be gained from the landowner before the trip. The section 'Reducing Risk on a Field Trip' (T2) is designed as a guideline for teachers. 'Safety First' (T3) should be read by students before the trip.

When to go scuffle/kick sampling

Timing is important, scuffle/kick sampling should not be undertaken between October and May as it is the fish spawning season (F02) and the eggs could be crushed underfoot. Only sample from the bank at that time of year using a throw net or dipping net.


You will need the following items of equipment:

• Nets

• Trays: White plastic trays are best or, if not, coloured trays with white card in the bottom

• Indicator papers: These test acidity (pH) and concentrations of nitrates

• Extras: Although not essential, the following can be very useful:
Plastic spoons - to pick up animals for closer inspection
Small paint brushes - as above if you can't get them with the spoon
Hand lens - useful for identification and also for seeing how spectacular some of the creatures really are

• Clothing: Wellington boots; jerseys and waterproof gear; spare socks; towel. You must be properly dressed and prepared for a worsening of the weather.


a) Where to go sampling
The scuffle sampling site should be a shallow, stony part of a river or stream. Such areas are known as riffles. Shallow means less than wellie-depth! A variety of stone sizes is best, say from about marble-size to tennis ball size. Check that permission has been granted to take samples in this part of the river.

b) Taking the sample
Most animals live among the stones where they won't be washed away so the sampling method will need to disturb the stream bed. The best method is the scuffle method. This involves disturbing the stream bed with a twisting or shuffling motion of the feet, moving slowly backwards in an upstream direction with the net virtually in front of you. The top edge of the net should just rest on the bed. In this way any animals dislodged by the motion of your feet will leave the stones and be swept into the net by the current. If there is too little current you may need to move the net from side to side to improve your catch. Make sure that someone is behind you watching that you don't trip up.

c) How many samples?
You should take three one-minute samples. Your party could divide up into three smaller groups and each take one sample. You could also split up the responsibilities within each group with one person taking the sample, one person timing it, one person making sure the sampler doesn't fall over, and so on.
But why three samples? Well, one sample may be a poor one (the bit of stream you choose may have been recently disturbed) and two samples could be widely different. Three samples, therefore, is the least number which should give you reliable results.

d) What if it isn't stony?
It may mean walking some way along the bank to find a suitable spot. Some areas may not have ideal sampling conditions. Try and avoid muddy riverbeds, but if it is all you can find, sample from the bank, using the net to disturb the mud surface.
You may find areas you want to sample have only large rocks or boulders. In this case, select a number you can lift easily and gently rub them while holding them in the mouth of the net. In this way, animals clinging to the rocks will be washed in. Carefully replace the rocks. Record how you sampled.

e) Looking for animals
Gently swish the net in the water to get rid of any mud in the sample. Half fill your tray(s) with undisturbed water and gently empty the contents of the net by turning it inside out in the tray. Most of the animals will swim out on contact with the water. Make sure all the animals have been removed and led the contents of the tray settle. Then look for movement - what's swimming, what's crawling, what's gliding along the bottom or looping from stone to stone. Use the Mini-beast Identification Sheet (B06b) to identify what is present.

f) Recording what you find
The exact method of recording will be explained by your teacher or leader. If you are using the Mini-beast Biodiversity Survey Sheet (B06c) the main purpose is to record how many different types of creatures you have found. You may also be asked to give some idea of how many animals there are of each type - a few (1-3); some (4 -14); a lot (more than 10; masses (more than 100). If required, these estimates will give valuable further information for analysing the results.

g) Returning the sample
Gently return the contents of the trays to the part of the stream from which you obtained the sample. Roll back any large stones that have been disturbed. Try and leave the site as you found it.


• Indicator species: The presence of some types of mini-beast can indicate the quality of the water. Each type of animal has been given a value indicating the extent to which it requires good quality water. For example, Stonefly nymphs need very clean, well-oxygenated water and score 10; Sludge worms can live in polluted mud and score 1. This doesn't mean that you might not find worms in quite clean water but they are not clean water indicators. On the Mini-beast Identification Sheet (B06b) each creature is given a 'value' after their name in brackets and those that are particularly useful indicator species have a star *.

• Other indicators: There are also some other clues to look out for such as kingfishers, dippers and sandmartins. They tell you something about the water because they feed on the animals that live in it. The presence of otters is a good sign too, not only is the site undisturbed but large fish are probably present indicating good water quality. Blanketweed and sewage fungus on the other hand are bad signs, indicating organic pollution - don't sample.

• Chemical testing: There are some chemical tests which can tell you about the state of the water. You can use pH indicator strips to measure the acidity (pH) of the water and nitrate indicator strips to measure the concentration of nitrates.
Acidity: if the water is acid (less than pH7) it does not necessarily mean it is polluted. Many of the rivers and streams in the South West are naturally acidic because of the type of surrounding rocks and vegetation. These river and streams can be easily damaged if real acid pollution comes along because they can't absorb its effects.
Nitrates: Nitrates are chemicals which plants need and are often found in fertilisers. High concentrations of these nitrates are sometimes found in farming areas where large amounts of fertilisers are used. High nitrate levels have been linked with certain diseases. They also fertilise the water causing it to become choked with weed and clouded with tiny suspended plants called algae.

• Results: Both chemical tests and using animals and plants as indicators have advantages and disadvantages and you can probably work out by now what some of them are. A good reason for using indicator species to test the quality of the water is that animals and plants are the real customers of our water systems - if they don't like the conditions, they disappear!

• Taking measurements: You can calculate the speed of the water by timing how long a twig takes to travel 2 metres in the water. Divide 2 by the number of seconds to get the speed in metres/seconds. The depth of water should also be measured where you sample.


During a field trip think of other users: The site at which you will be sampling will always have other uses other than fieldwork! Be careful that your activities do not interfere with others.

Respect ownership: You have no statutory right of access to most land. When you are given permission to carry out work on someone's land, make sure you respect his or her wishes.

Encourage respect for fieldwork: Show your intention is serious and reflect this in the way the group behaves. If you have a vehicle, be careful it does not cause an obstruction. Follow the Country Code.

Leave the area as you found it: Try to keep your movements to a minimum so as not to damage the area. Especially take care not to walk on crops or to damage the banks of the river. Do not take specimens home - they will only die and it may be illegal.

Choose your area carefully; If you intend to continue your fieldwork at other sites (and you are encouraged to do so), try to avoid areas that are intensively used by field parties. Too much disturbance from visitors can reduce the value of the site for fieldwork. If in doubt, consult the Local Trust for Nature Conservation.

Avoid disturbing plants and animals and the unnecessary collection of specimens: Keep the number of samples taken to a minimum and always return specimens to the same location from where they came. If you turn over stones to look for animals, turn them back again. Flowers, plants, mosses and lichens should not be taken.

These surveys and sampling expeditions are about conservation - often described as the wise management of the planet's resources. If you follow the guidelines given above, there will be little damage to the environment and no one, not even the plants and animals, will regret your visit. You will have been involved in conservation, enjoyed the environment and learnt a great deal.