91154 Marine invertebrates assessment
1. The interspecific relationship between abundance and occupancy for intertidal invertebrates is a positive one, whereby an organism that is more abundant has a higher occupancy compared to those that are less abundant.

Log10abundance vs Occupancy
0.9
0.8

[CELLRANGE]

0.7

Occupancy

0.6
[CELLRANGE]
0.5
0.4
0.3
0.2

[CELLRANGE]

0.1

[CELLRANGE]
[CELLRANGE]

[CELLRANGE]
[CELLRANGE]

[CELLRANGE]
0
-1.5

-1

-0.5

0

0.5

1

1.5

Log10abundance

2. Two ecological mechanisms underpinning a positive abundance-occupancy relationship are that locally abundant species will be widespread, while rare species are narrowly distributed.
3. A negative correlation is seen on the rank abundance curve below. The shallow slope (m = 0.3124) indicates a high degree of evenness.

Rank vs Log10abundance
1.5

Log10abundance

1
0.5
0
-0.5
-1

y = -0.3124x + 1.3699

-1.5
0

1

2

3

4

5

Rank

6

7

8

9

91154 Marine invertebrates assessment
4. Three advantages of rank abundance curves are: they visually show how ecological systems are organised, species richness can be quickly identified and species evenness can be quickly identified. 5. According to the data as seen below, there does not seem to be a clear relationship between the log10bodysize and log10abundance as a few of the different species had similar body size data but with very different abundance data.

Log10meanbodysize (mm) vs Log10abundance
1.5

Log10abundance

1
0.5
0
-0.5
-1
-1.5
0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

Log10mean bodysize (mm)

6. 3 possible reasons for an unexpected body size – abundance relationship could be that