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Is there a difference in biodiversity between two different ecosystems, and which one is best at supporting life?

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BIODIVERSITY COURSEWORK

AIM:         To see if there is a difference in biodiversity between two different ecosystems, and to see which one is best at supporting life

INTRODUCTION:        In this experiment I have looked at two different ecosystems at my school.

The first ecosystem was behind the English block. Its up on a hill, higher than any other site in the school grounds. It gets lots of sunlight because its up on a hill, also there are not many trees in the ecosystem so the sunlight can reach the ground to the plants below. The only source of water for the ecosystem is rainwater so in the summer it is very dry and the plants die.

        The second ecosystem is down at the bottom of the school field it is behind the bushes by the field and has a river running through it. There are lots of trees and bushes in the area with lots of other plants that have lush green leaves. This ecosystem doesn’t receive a lot of sunlight because the trees catch it before it reaches the ground so only a little light ever does reach the ground. This ecosystem is very low compared to the other area. It gets all the rainwater that runs off the field as it’s on a bit of a slope.

        Comparing the two ecosystems I can see that the English block forest gets very dry, with only rainwater to water it, but it does get lots of sun light. So in the summer it looks very dry. Whereas the river ecosystem only gets a little sunlight, but has a lot of water from the river and the rain. So it’s very lush and green. The distance between the two systems is about 1km.

PRELIMINARY WORK:        At the start of the experiment I went down to the two ecosystems and done some preliminary work. This consisted of getting 4-meter sticks and laying them randomly in one place on the ground. Then I counted all the plants in the 1-meter square. I did this in both ecosystems. I had to also identify all the plants in the square and list how many there was. Then with all this information I worked out the Biodiversity for the two squares.

Here are my results for the ecosystem behind the English block:

List of plants I counted:

  • 6 wild barley
  • 95 bent grass
  • 185 goose grass
  • 42 ivy

The biodiversity of this quadrat is 2.4.

Here are my results for the river ecosystem:

List of plants counted:

  • 2 cow parsley
  • 3 creeping buttercup
  • 1 bindweed
  • 5 ground elder
  • 7 goose grass
  • 6 common grass

The biodiversity of this quadrat is 5.5

image00.pngA table to show the difference in biodiversity between the two quadrats.

WHAT IS BIODIVERSITY AND HOW DO YOU WORK IT OUT:

Biodiversity means variety of living things. You can work out an index of biodiversity to compare two ecosystems like I have done in the above section. To do this you have to follow this equation:

D = N (N-1)

     + n (n-1)

N = total number of organisms of all species found

n  = total number of organisms of a particular species found  

 +   = sum of all organisms of a particular species.

By using this equation you can work out the biodiversity index of a certain area. The higher the number, the higher the biodiversity. The lower the number, the lower the biodiversity. Which means there’s lots of plants in the ecosystem or there are many plants in the ecosystem.

RESEARCH:                In this section I will find out about the plants that are in the two ecosystems.

IVY: Is a climbing trailing plant, which grows wildly across Europe. Grows in regular garden soil, can live in full sun if given lots of water, also grows well in the shade.

COMMON GRASS: Also known as common reed grass. It is common in North America, and other places. Grows in moist soil and likes marshes.

OAK TREE: _        Found wide in Europe, grows in deep, loamy soil that is moist but not waterlogged. They can be planted in the autumn right through to spring, when new growing starts. Oaks need sunlight and water to survive.

CREEPING BUTTERCUPS: Originally found in Northern England. They need moist, fertile sandy soil in a shaded or semi shaded area to grow, with a good supply of water.

GOOSE GRASS: Found in wasteland, lawns, and fields. It is often seen in compacted soils that border trails and roads. Once goose grass becomes established, annual reifications are likely to occur. It is usually found in full sun and often in poorly drained or compacted soil.

COW PARSLEY:  Cow parsley inhabits hedgerows, field edges, and the edges of woods and sometimes-waste ground.

GROUND ELDER:Pernicious weed of cultivated, damp ground. It is normally found in shady edges of forest, garden, and parks.

BINDWEED:        Bindweed is a perennial weed that spreads from an extensive rootstock as well as from seed. Field bindweed tolerates a great range of environmental conditions and elevations and is found in all types of ground, including cultivated fields and waste places. It grows best on fertile, dry or moderately moist soils and is extremely difficult to control.

PREDICTION:        I predict that the difference in the biodiversity between the two ecosystems will be very large. I predict this because when I look at the biodiversity scores I got on the preliminary quadrats, there is a big difference in the two scores. The forest quadrat had a biodiversity score of 2.4, whereas the river quadrat had a score of 5.5. The difference between them is 3.1. There were more plants in the river quadrat then the forest quadrat, so this makes a difference right away. The forest doesn’t get a lot of water so it can’t support much plant life whereas the river has lots of water because it has a river in it. The river is also more shaded and doesn’t get direct sun light unlike the forest so this also plays a part in why I think there will be a big difference in the ecosystems.

INFORMATION I HAVE COLLECTED:        In the test I collected a lot of information. This was divided into two groups, which were abiotic factors, and biotic factors. Abiotic factors are the non-living things, which affect an ecosystem. Biotic factors are the living organisms in the ecosystem.

The abiotic factors were:

  • Light intensity
  • Temperature of soil
  • PH of soil
  • Water content of soil

The biotic factors were:

  • The plants (quadrat counts)

METHODS I USED: To collect the above information I used lots of different methods:

  • Light intensity: To collect this information I used a piece of equipment called a datalogger, which had a light senor connected to it. The light sensor measures the amount of light that is in an area. I measured the light intensity in each of my quadrats.  
  • Temperature of Soil: To collect this information I put a thermometer in the ground where each of my quadrats were, left it a few minutes then took down its readings
  • PH of Soil: I collected this by taking four samples of soil from the same ecosystem, mixing them in the same bag. Then I put some of the soil into 5 boiling tubes, added some water, then I added some universal indicator into the boiling tubes, then I recorded the PH by looking at the colour of the indicator and comparing the colour to a chart of PHs. I done this for both ecosystems.  
  • Water Content of Soil: To collect this I used the same soil I got from the PH test. I got a tin lid put in on some scales and weighed it. I recorded this weight. Then I added some soil to the tin lid. Weighed it again. Then I placed to over a Bunsen burner for 5 minutes to burn off the water in the soil. After the 5 minutes I put tin back on the scales and weighed it again. With this weight I had to subtract the weight of the tin from the overall weight. With the left over I subtracted it from the weight before I put it over the Bunsen burner. After this I had the water content of the soil. I done this 5 times for both ecosystems.
  • The Quadrats: This was when I randomly selected an area of the ecosystem and put down the four meter sticks and counted every plant in the square. Recording how many there were of each plant. I done this in both ecosystems. With 9 quadrats.    

THE DATALOGGER AND HOW TO USE IT:        This is how to set up and use the datalogger with light sensor.

  1. Connect the TI-83 calculator and the CBL unit together using the TI-83 link cable
  2. Connect the light senor to channel 1 on the CBL unit
  3. Turn on the calculator
  4. Press PRGM on the calculator
  5. Select CHEMBIO using arrows, when found press ENTER
  6. Press ENTER two more times
  7. Select SETUP PROBES, press ENTER
  8. Press 1 for number of probes, press ENTER
  9. Select OTHER SENSORS, press ENTER
  10. Select LIGHT, press ENTER
  11. Press 1 for channel number, press ENTER
  12. Select COLLECT DATA, press ENTER
  13. Select MONITOR INPUT, press ENTER
  14. Place light sensor on the ground with the sensor side facing directly towards the sky
  15. Read the value off the CBL and record it.

RESULTS:        Here are all my results that I got from my tests in the above methods. I have put them into two sections; these are The Forest Ecosystem and The River Ecosystem.  

The Forest Ecosystem

Here are the results from the quadrat tests:

Wild Barley

70

Bent Grass

34

Common Grass

600

Total

704

Biodiversity

1.4

Quadrat 1                               Quadrat 2                               Quadrat 3          

Bent Grass

85

Rye Grass

103

Goose Grass

1

Oak Tree

1

Total

190

Biodiversity

2.1

Bent Grass

68

Common Grass

550

Maple Tree

1

Goat Willow

1

Stinging Nettle

14

Total

634

Biodiversity

1.4

Quadrat 4                               Quadrat 5                                    Quadrat 6

Goose Grass

3

Rosemary

2

Sweet Celery

3

Common Grass

200

Rye Grass

18

Total

226

Biodiversity

        2.2

Wild Barley

9

Bent Grass

10

Perennial Grass

28

Rye Grass

14

Total

61

Biodiversity

3.3

Cow Parsley

1

Rye Grass

14

Common Grass

179

Total

194

Biodiversity

1.9

Quadrat 7                               Quadrat 8                                  Quadrat 9

Bent Grass

8

Ivy

18

Goose Grass

2

Total

28

Biodiversity

2.1

Goose Grass

2

Dandelions

5

Total

7

Biodiversity

1.5

Oak Tree

1

Bent Grass

111

Perennial Grass

52

Goose Grass

32

Total

196

Biodiversity

2.5

The Average biodiversity is 2.1

Here are the results for the light intensity and temperatures of the quadrats

                                                Quadrat 1                                  Quadrat 2

Temperature (oC)

15

Light Intensity

0.898

Temperature (oC)

17

Light Intensity

0.876

Quadrat 3                                      Quadrat 4                                    Quadrat 5         

Temperature (oC)

13

Light Intensity

0.86

Temperature (oC)

18

Light Intensity

0.886

Temperature (oC)

15

Light Intensity

0.867

Quadrat 6                                      Quadrat 7        Quadrat 8

Temperature (oC)

16

Light Intensity

0.875

Temperature (oC)

15

Light Intensity

0.854

Temperature (oC)

17

Light Intensity

0.841

Quadrat 9

Temperature (oC)

14

Light Intensity

0.871

The average temperature is 15.6

The average light intensity is 0.870

Here are the results for the ph levels of the soil

Test

PH level

1

16

2

14

3

15

4

15

5

16

The average PH level is 15.2

Here are the results for the water content of the soil

Test No.

Initial Mass (g)

Final Mass (g)

Difference (g)

1

11.39

8

3.39

2

5.57

2.85

2.72

3

4.71

2.03

2.68

4

2.68

1.81

0.87

5

3.96

1.98

1.98

The average water content is 2.33

THE RIVER ECOSYSTEM:        Here are the results for the quadrats

Quadrat 1                               Quadrat 2                               Quadrat 3

Stinging Nettle

43

Common Grass

15

Total

58

Biodiversity

1.6

Ivy

45

Stinging Nettle

1

Total

46

Biodiversity

1.1

Stinging Nettle

14

Total

14

Biodiversity

1

Quadrat 4                                  Quadrat 5                        Quadrat 6

Creeping Buttercup

6

Total

6

Biodiversity

1

Ivy

10

Oak Tree

1

Total

11

Biodiversity

1

Dock Leaves

12

Stinging Nettles

17

Grass

20

Total

49

Biodiversity

3

Quadrat 7                                Quadrat 8                              Quadrat 9

Stinging Nettle

7

Ivy

27

Little Leave

3

Total

37

Biodiversity

1.8

Dock Leave

1

Ivy

37

Stinging Nettle

2

Total

40

Biodiversity

1.2

Ivy

60

Stinging Nettle

6

Total

66

Biodiversity

1.2

The average biodiversity is 1

Here are the results for the light intensity and temperature of the quadrat:

Light Intensity

0.927

Temperature (oC)

14

Quadrat 1                                 Quadrat 2

Light Intensity

0.92

Temperature (oC)

19

Light Intensity

0.919

Temperature (oC)

18

Light Intensity

0.922

Temperature (oC)

16

Light Intensity

0.922

Temperature (oC)

16

Quadrat 3                                Quadrat 4                                Quadrat 5

Quadrat 6                                  Quadrat 7                           Quadrat 8

Light Intensity

0.914

Temperature (oC)

15

Light Intensity

0.92

Temperature (oC)

17

Light Intensity

0.927

Temperature (oC)

18

Quadrat 9        the average light intensity is 0.882   and temperature is 16

Light Intensity

0.564

Temperature (oC)

15

Here are the results for the PH levels of the soil

Test

PH Level

1

8

2

8

3

9

4

7

5

7

The average PH level is 7.8
 

Here are the results for the water content of the soil

Test No.

Initial Mass (g)

Final Mass (g)

Difference (g)

1

12.89

10.3

2.59

2

10.07

7.79

2.28

3

15.54

11.03

3.91

4

11.6

9.09

2.51

5

14.18

11.05

3.13

The average water content is 2.88

These are all the results I collected

CHARTS:        I have put some of the results into charts so I can compare them easily.

image01.png

image02.png

image03.png

image04.png

image05.png

image06.png

CONCLUSION:

Test

Forest average

River average

Biodiversity

2.1

1

Light intensity

0.87

0.882

Temperature

15.6

16

Water content

2.33

2.88

PH level

15.2

7.8

 This table shows the averages

By looking at my averages tables and my results I can see that the ecosystem that is the best at supporting life is the river ecosystem. This means that my prediction was correct.

The river ecosystem is the best at supporting life because it gets more light intensity, which means the photosynthesis can take place, so the plants produce more glucose than the ones in the forest. The forest may have more biodiversity, than the stream, but that doesn’t mean it can’t support more life.

The soil in the stream has a neutral PH which is good as it is only slightly alkaline which means the plants can survive better in this soil than the soil in the forest which has a high alkaline soil content. The difference in the biodiversity between the two isn’t very big, like I predicted.

EVALUATION:        If I could do this piece of coursework again I would, make sure I done all the experiments on the ecosystems in the same month if possible the same week or day. As I started this coursework in June and then didn’t finish it until September. By then the weather had changed and the soil had got colder and autumn was setting in.

I think the water content test wasn’t very reliable because as well as burning off the water in the soil I was also burning the organic content of the soil so this made the soil lighter. The temperature taking using a thermometer wasn’t very good because the thermometer snapped once in the soil and the reading wasn’t very clear. So it would be better if I used the datalogger to take the temperature, as it would have been more reliable.

When looking back on my results I can see that quadrat 9 on the light intensity is much lower than the rest, this could be put down to the area being covered by more tree cover or the datalogger user made a mistake. Again going back to the thermometer I can see that the temperature of the soil in both ecosystems is varied which means it would have been better to use another device then a thermometer to record the temperature.

If I could have had a whole day to do the tests on the ecosystems they would have been more reliable because the weather conditions would have been the same, the humidity would have been the same, as well as the temperature of the day and the wetness of the soil.    

This student written piece of work is one of many that can be found in our AS and A Level Genetics, Evolution & Biodiversity section.

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