Insolation –
- This was kept constant by carrying out the experiment during the same time of the day
Soil pH –
- This was difficult to keep constant, however once another group had measured it had been found that the pH of the soil was approximately 8.0 at both sites
Precipitation –
- This was not a problem since there was no precipitation during the days in which the experiment was carried out
Light intensity –
- Once again it was difficult to control; the light intensity was stronger on Day 1 of the experiment. But in order to make it as fair as possible, we carried out the experiment at the same time of the day
Independent variables – Number of samples
- This was controlled by taking 15 samples on each site; the Groenplan and woodland area
Quadrat size
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We used a 0.5m2 quadrat instead of using a 1 m2 quadrat
Area of the site
- We looked at areas of 40 metres by 25 metres on both sites
Species chosen
- In the woodland we only looked at a few species since there were too many species in the woodland. We looked at those that were most common in the first two samples.
Risk assessment – We used gloves in order to ensure that the poisonous plants would not affect us. Also we ensured our feet were fully covered so that our feet were not affected.
DATA COLLECTION
Uncertainties in Measurement and errors –
In order to ensure that we had the best results, we carried out the experiment 15 times in both locations. However, since there were trees in the woodland, it was difficult to measure the sedentary species in that specific area, and so when a tree was in the selected quadrat area (randomly) we placed the quadrat next to the tree, to best represent the data.
While conducting the experiment we felt that 15 samples was too little, but considering the time constraint it was the best sample that was capable of being achieved. We felt that this could effectively highlight the distribution.
Aslo in the woodland, some of the plants were not taken into consideration since there was not a large abundance of them and it was difficult to collect the information of all the sedentary species in the woodland. Therefore after analysing the first few sample we came to the conclusion of which species were in the largest abundance and this was chosen to represent the data of the woodland.
DATA PROCESSING AND COLLECTION
Errors in data collection – While working out the percentage cover in the woodland area, we were not provided the divided quadrat which meant that the percentage cover of sedentary species were approximated. This also lead to the value of leaf litter being valued as the remaining percentage found out in the results. Also since it was not possible to represent all the plants in the woodland area, we had to limit ourselves to 8 plants and leaf litter in order to make the experiment more accessible.
CONCLUSION
After having analysed all the resultsm we can see that the biodiversity is greater in the woodland area than in the Groenplan. This is because the Groenplan was managed by a group of people, whereas the only way in which the woodland area was affected was by trampling of students. However the trampling did not cause a change to the biodiversity since the plants were not removed by mowing of the area, which was the case in the Groenplan.
From the results, we can see that in the Groenplan that the area was mostly covered by grass and clover, which was completely opposite to the woodland area. Within the woodland, there was no grass and clover, in fact the woodland was mostly covered with bramble and leaf litter. None of the two found in the woodland, were found in the Groenplan.
As we can see the results support my original hypothesis. We can observe that the number of plants found in the woodland are greater (also the leaf litter represents a mixtures of leaves from trees and other plants) further emphasising the greater bio diversity. Also the data from the Groenplan suggests that only two plants dominated to area, whereas it was different for the woodland area since there was more of a split in the percentage cover of different species.
EVALUATION
After having completed the experiment, we can consider a number of factors and how the experiment could have been improved if the experiment was run differently. Firstly, since the experiment was in school, the number of quadrats required were minimal which made it difficult to have an exact percentage cover. This meant that results were approximated more often than expected.
While conducting the experiment, the site was being exploited by a large group of people all working on different experiments. This meant that the measuring tape along which the quadrat’s position was determined was moved accidentally, which may have biased the results. Also while going to a specific location for a quadrat, if it was being used or was occupied by a tree, we were forced to take the sample next to the actual postition. This could have affected the results since the sampling was no longer random as it was changed by other exogenous factors.
I feel that when carrying out this experiement again, the number of people working on the site should be reduced, this will ensure that the test is fair. Also it should be kept constant whether the student is provided with a divided or undivided quadrat to make the experiment as fair as possible. Finally, it must be ensured that when something comes in the way of the sampling, then the same method for a shift in the quadrat is agreed.
Lastly, I feel that this experiment needs further investigations. It would be interesting to observe the results during different seasons of the year as well as different times during the day. This experiment was run during the afternoon on a sunny day in June. The invetigator should consider looking to try and remove the pollution and waste in both the Groenplan and woodland area to make the test fair.