Maggie and I chose to investigate the plant biodiversity in
different areas of the forest. We hypothesised that plant biodiversity would be
higher in the locations exposed to the sun due to the plants photosynthesising and not having to compete for sunlight.
We decided we would examine three areas of the forest using two variables the
first was elevation and the second looked at the level of light. If you follow
the path through the forest you will notice that the incline increases the
further into the forest you go. We followed the path to the outside perimeter
of the forest and therefore the highest point we could reach. Once we had selected
a sampling location we randomly threw a 10x10 grid into an area in the shade,
then an area in the sunlight and measured the plant diversity in the grid. The
results were recorded in a table along with the light measurement in (lx) and
the elevation of the sampling site. This process was repeated in a sampling
area of low, medium and high elevation and random samples were taken from areas
in shade and sunlight. We analysed the data using two different methods, the
basic biodiversity Index and the Simpson Index of Diversity. When comparing the
data, we found that the basic biodiversity index and the Simpson index of diversity
showed that plant biodiversity was highest on medium ground elevation in the
light, but this is probably due to the woodlands being far less dense then the
lower and higher ground where we found that one species appeared to be more dominant
then another. We were however, surprised to find that a greater number of
species was found in all the sampling areas in the shade. There were flaws in
our experiment however, so if we were to repeat the experiment again we would
make sure that we were able to ascertain that the areas we sampled in the shade
were under a canopy and in the shade at all times.
The raw data and calculations collected from our
investigation are shown in the tables below.
West lower ground
Species
|
Percentage
covered %
|
Sunlight
or shade
|
Light
(lx)
|
B
|
85
|
Sunlight
|
258 x 100
|
C
|
3
|
Sunlight
|
258 x 100
|
E
|
1
|
Sunlight
|
258 x 100
|
D
|
5
|
Shade
|
38 x 100 (378 x 10)
|
B
|
83
|
Shade
|
38 x 100 (378 x 10)
|
A
|
11
|
Shade
|
38 x 100 (378 x 10)
|
South path medium
ground
Species
|
Percentage
covered %
|
Sunlight
or shade
|
Light
(lx)
|
B
|
100
|
Shade
|
190 x 100
|
A
|
10
|
Shade
|
190 x 100
|
F
|
4
|
Shade
|
190 x 100
|
G
|
6
|
Shade
|
190 x 100
|
F
|
6
|
Sunlight
|
223 x 100
|
A
|
19
|
Sunlight
|
223
x 100
|
B
|
2
|
Sunlight
|
223 x 100
|
North higher ground
Species
|
Percentage
covered %
|
Sunlight
or shade
|
Light
(lx)
|
A
|
1
|
Sunlight
|
215 x 100
|
A
|
1
|
Shade
|
21 x 100
|
B
|
70
|
Sunlight
|
215 x 100
|
B
|
100
|
Shade
|
21 x 100
|
C
|
1
|
Shade
|
21 x 100
|
D
|
1
|
Shade
|
21 x 100
|
Using the raw data collected we calculated a Biodiversity
score, using 2 different methods.
Method 1 - a Basic Biodiversity Index and method 2 - Simpson
Index of Diversity.
Method 1 – Basic
Biodiversity Index
Lower ground:
Sunlight or shade
|
Number of species
|
Total number of individuals
|
Basic Biodiversity Index
|
Light
|
3
|
89
|
0.0337
|
Shade
|
3
|
99
|
0.0303
|
Medium ground:
Sunlight or shade
|
Number of species
|
Total number of individuals
|
Basic Biodiversity Index
|
Light
|
3
|
27
|
0.1111
|
Shade
|
4
|
120
|
0.0333
|
Higher ground:
Sunlight or shade
|
Number of species
|
Total number of individuals
|
Basic Biodiversity Index
|
Light
|
2
|
71
|
0.0281
|
Shade
|
4
|
103
|
0.0388
|
Method 2 - Simpson
Index of Diversity
Lower ground light:
Species
|
n (number of individuals)
|
n(n-1)
|
B
|
85
|
7140
|
C
|
3
|
6
|
E
|
1
|
0
|
Total N
|
89
|
|
Total n(n-1)
|
7146
|
D = 1 - (7146/7832) = 0.087
Lower ground shade:
Species
|
n (number of individuals)
|
n(n-1)
|
A
|
11
|
110
|
B
|
83
|
6806
|
D
|
5
|
20
|
Total N
|
99
|
|
Total n(n-1)
|
6936
|
D = 1 – (6936/9702) = 0.286
Medium ground light:
Species
|
n (number of individuals)
|
n(n-1)
|
A
|
19
|
342
|
B
|
2
|
2
|
F
|
6
|
30
|
Total N
|
27
|
|
Total n(n-1)
|
374
|
D = 1 – (374/702) = 0.467
Medium ground shade:
Species
|
n (number of individuals)
|
n(n-1)
|
A
|
10
|
90
|
B
|
100
|
9900
|
F
|
4
|
12
|
G
|
6
|
30
|
Total N
|
120
|
|
Total n(n-1)
|
10032
|
D = 1 – (10032/14280) = 0.297
Higher ground light:
Species
|
n (number of individuals)
|
n(n-1)
|
A
|
1
|
0
|
B
|
70
|
4830
|
Total N
|
71
|
|
Total n(n-1)
|
4830
|
D
= 1 – (4830/4970) = 0.281
Higher ground shade:
Species
|
n (number of individuals)
|
n(n-1)
|
A
|
1
|
0
|
B
|
100
|
9900
|
C
|
1
|
0
|
D
|
1
|
0
|
Total N
|
103
|
|
Total n(n-1)
|
9900
|
D
= 1 – (9900/10506) = 0.057
