A quadrat can be used in quantitative method of estimating population of animals provided the animals DO NOT MOVE e.g. Barnacles on a rocky sea shore (or move very, very slowly e.g. Limpets on a sea shore). Method 1  Frequency or percentage cover can be estimated the same was as the plants are with either a frame or a point quadrat. Make sure the animals are suited to this type of measurement Method 2 1.Population density is a more common parameter measured for animals – using a frame quadrat OF KNOWN AREA e.g. 0.5m x 0.5 m (or 0.25m 2 ). Use the same random ‘throwing’ of the quadrat but when the quadrat lands count the number of the target organism present. Repeat the procedure many time (more repetitions = more accuracy). Record as with plants and get the average number of organism per quadrat. Then calculate the number of organism per metre (in the example above simply multiply the average number per quadrat by 4). 2.Sometimes it is required to calculate the number in the selected section of the ecosystem – to do this you need to measure and calculate the area of the experimental section and then multiply the average per metre by the area (in metres 2 ) Simulation of the Capture /Recapture method – more common for animals than the quadrat is detailed in next 2 slides....

Simulation of Capture/Recapture method of estimating the population of an animal Materials: Simulated an ecosystem/habitat (e.g. a tupperware container) Simulated organisms --- peas Simulated trap/collection methods – e.g. specimen bottle, small yoghurt carton etc. Marker -- spray paint, nail varnish, typex etc Method: 1. Catch as many organisms as possible e.g. you could use specimen bottle 3 times 2. Count number caught and 3.Record number 4.Mark those you caught discreetly – why? (use quick dry spray paint or other) 5.Release them back into ecosystem exactly where you caught them (why?) 6.Catch as many as possible again – use same collecting apparatus (3 traps) 7.Count them and record number and 8.Note how many of the them are marked (i.e. recaptured) and 9.Record the number

Calculation Population = Number caught 1 st time x number caught 2 nd time Number that were recaptured (i.e. marked) e.g 100 x = 200 population Note: if you are asked to estimate the population range, you must repeat the activity at least once more and then the result i.e. the range would be something like e.g. from 200 – 300 (citing your lowest and your highest results)