1. Ecology Calculations Dominican College, Griffith Ave

2. Quantitative Analysis Numbers!!

3. Our Habitat The Rocky Seashore

4. Description: Sitting on the boulders facing the sea, we mark off a section of the seashore 20m wide and 50m towards the sea The total area is 1000m 2

5. The Rocky Seashore Making a Map: On a sheet draw a rectangular box, 20cm wide by 50cm long This represents your habitat at a ratio of 1cm:1m Put in the direction

6. The Rocky Seashore Making a Map: Put in main parts of what you see These include rock pools, large boulders/rocks, large quantities of named algae….. MAKE A KEY

7. Equipment Mammal trap Pitfall trap Insect net Pooter Quadrat Grid Quadrat

8. Method 1 – Capture/Recapture Used for Animals

9. Capture/Recapture Cntd. The Pitfall Trap As we are on a rocky seashore, the type of animal I have selected is the rough periwinkle which is found on the upper seashore. The upper seashore will not flood (except during a storm/lunar high tide)

10. Capture/Recapture Cntd. The Pitfall Trap Dig a hole and insert a jar The jar should be at sand level Put a flat stone over the lid of the jar Using two pebbles, ensure that the flat stone has a gap to allow rough periwinkles fall into the jar

11. Capture/Recapture Cntd. The Pitfall trap Set up a number of Pitfall Traps on the upper seashore Leave for 24 hours Inspect the jars after 24 hours and count and mark the rough periwinkles

12. Capture/Recapture Cntd. The Pitfall trap Marking the Rough Periwinkles: Mark with a non-toxic paint (Not to harm the animal) Mark on the underside (To protect it from predators) Mark with a temporary paint (So that it clears quickly to prevent predation)

13. Capture/Recapture Cntd. The Pitfall trap Release the rough periwinkles in the vicinity and re-set the pitfall traps. After another 24 hours, check the traps and count the number of rough periwinkles, noting also the number which have a paint mark on them

14. Capture/Recapture Cntd. The Pitfall trap Calculations: Total Population= No. caught on 1st visit x No. caught on 2nd visit No. of marked animals recaptured on the 2nd visit

15. Capture/Recapture Cntd. The Pitfall trap Calculations: Sample Answers No. caught and marked on 1st visit = 20 No. caught on 2nd visit =15 No. of marked animals caught on 2nd visit = 5 Total population = 20 x 15 = 60 5

16. Method 2 – Percentage Frequency

17. Percentage Frequency Throw Ten Quadrats (1m X 1m) FREQUENTLY MARKS COVER NUMBERS

18. Percentage Frequency If Present, Tick Yes If Absent, Tick No Calculate the fraction, then the percentage FREQUENTLY MARKS COVER NUMBERS

19. Percentage Frequency FREQUENTLY MARKS COVER NUMBERS

20. Percentage Frequency Calculations: Sample Answers For Bladder Wrack Found in 7 out of 10 quadrats Hence 70 % Frequency FREQUENTLY MARKS COVER NUMBERS

21. Method 3 – Percentage Cover

22. Percentage Cover A grid quadrat is used. This is 1m X 1m divided into 100 squares which is 1m 2 in area Some quadrats may be 0.5m X 0.5m divided into 25 squares, which is 0.25m 2 Great care must be taken to read any data that you may have to use in a question FREQUENTLY MARKS COVER NUMBERS

23. Percentage Cover FREQUENTLY MARKS COVER NUMBERS

24. Percentage Cover We select 10 ‘hits’ on every quadrat A pen is placed at this point and if it touches an organism it is recorded as a “hit” for that organism FREQUENTLY MARKS COVER NUMBERS

25. Percentage Cover FREQUENTLY MARKS COVER NUMBERS

26. Percentage Cover Calculations: Sample Answers For Bladder Wrack Found in 34 ‘hits’ from a potential of 100 Hence 34 % Cover FREQUENTLY MARKS COVER NUMBERS

27. Method 4 – Population Density

28. Population Density The number of each plant in each quadrat is counted and recorded and then extrapolated as per the whole habitat

29. Population Density

30. We found that there were 1.9 bladder wracks per 1m 2 As there is 1000m 2 in the habitat, we can find the density by saying: If we have 1.9 bladder wracks per 1m 2, then we should have 1900 per 1000m 2

31. Method 5 – Distribution

32. A)-Distribution We use a line transect: Unfurl a 50m rope marked at 1m intervals from the upper shore to the lower shore Note the organism that ‘touches’ the ‘mark’

33. B)-Population Distribution We use a belt transect: Unfurl two 50m ropes marked at 1m intervals from the upper shore to the lower shore, with a separation of exactly 1m 2 In essence this is now 50 X 1m 2 quadrats Name these, 1 to 50

34. B)-Population Distribution We use a belt transect: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 …………… 50 To Lower Shore

35. B)-Population Distribution Take the populations of the organisms chosen Graph these

36. B)-Population Distribution

37. Section 2 – Calculation Errors

38. Calculation Errors No. caught on 1st visit x No. caught on 2nd visit No. of marked animals recaptured on the 2nd visit Getting the formula incorrect

39. Calculation Errors The use of a quadrat that ISN’T 1m 2

40. Calculation Errors EG. 1 - Percentage Cover: A grid quadrat 0.5m X 0.5m, was thrown 10 times in a habitat of 3600m 2. 25 hits are taken in each quadrat Quadrat No. 12345678910 No. Hits for Bladder Wrack 1150002321299

41. Calculation Errors EG. 1 - Percentage Cover Cntd. How many ‘hits’ did you get?.................80 How many potential ‘hits’ were there…250 As a fraction, this is 80 250 As a Percentage, 80 * 100=32% 250

42. Calculation Errors EG. 2 - Population Density: A Grid quadrat 0.5m X 0.5m, was thrown 10 times in a habitat of 3600m 2. 25 hits are taken in each quadrat Quadrat No. 12345678910 No. Hits1150002321299

43. Calculation Errors EG. 2 - Population Density: Find the population per 1m 2 and extrapolate

44. Calculation Errors EG. 2 - Population Density: 80 in 10 quadrats, so the number of Bladder wracks per 1m 2 is

45. Calculation Errors EG. 2 - Population Density: NOT 8 per 1m 2 Because the 10 quadrats do not amount to 10m 2 Because each quadrat is only 0.25m 2

46. Calculation Errors EG. 2 - Population Density: 80 in 10 quadrats (0.25 m 2 ), So, 80 in 25m 2 So the number per 1m 2 is 3.2

47. Calculation Errors EG. 2 - Population Density: But we’re not finished yet!! 3.2 per 1m 2 (3.2 X 3600) in 3600m 2 Answer = 11520 in habitat