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investigation was carried out on the beach sand dunes

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Biology Coursework Introduction: This investigation was carried out on the beach sand dunes, a few miles off Leeson House in Dorset. Aim: The main aim of my investigation is to see how the percentage (%) cover of ling heather is affected by the pH of the soil with increasing distance from the sea. Expect: From the theory that I have provided, I would expect to see that with increasing distance inland, with the dunes, the percentage cover will gradually start to increase. Hypothesis: I predict that with increasing distance from the sea the soil pH will increase and therefore the percentage over of ling heather will increase My null hypothesis is: With increasing distance from the sea, the pH of the soil does not affect the percentage cover of Ling Heather. Statistical Analysis For this investigation I will use spearman's rank as my statistical analysis. I will use this as I wish to see whether there is a significant correlation between soil pH and percentage cover of Ling Heather Theory supporting Hypothesis: Ling is Heather or also known as Calluna vulgaris, it is a perennial shrub which grows up to 20-50cm tall. Ling is a plant which is mostly found in Europe and also in parts of Asia. It only occurs in mostly well drained, acidic soils and grows in sunny situations with moderate shade In psammosere succession there are 4 main types of dunes: * Embryo-Dunes * Fore-dunes * Grey-dunes * Mature-Dunes The embryo dunes have yellow sand and contain the pioneer species: Marram Grass, these with there long roots, binds the soil together and are able to withstand wind pressure and saline conditions. ...read more.


Soon after, each difference calculation will then needed to be squared; this is to exclude any negative numbers from the difference rank calculation previously. The total sum of the squared difference will then be calculated. From this, all the figures required will be substitute into the Spearman's rank Formula. Once the calculation is complete, I will then need to check the figure against a table of critical values to see whether my results show a correlation and also whether or not I can accept or reject my null hypothesis. Justification of Choice of Apparatus and Materials: Apparatus / Materials Chosen Alternative Apparatus/Materials Reason for Choice Measuring Tape Measuring Ruler I will be using a measuring tape for this investigation. I am using this over the ruler because it is a very flexible tool; it can easily be wounded up and reaches 50m in length smoothly. It is also lightweight and also compact. It is also a much more accurate reading tool when calculating distances over hills. Quadrate Measuring Ruler By using a quadrate, it automatically marks out a 1 x 1 sq. metre area. It also contains smaller box holes, a total of 100m each representing 1cm2 and can easily be use to read off percentage cover of plants. This is much easier, accurate and efficient that using the measuring ruler since percentage cover will not be calculated accurately. Sample Bags Sample Palettes In using sample bags, they are re-sealable and also airtight, therefore allowing for no dropping the sample and also holding the moisture of the soil intact. ...read more.


d� 10 0 6.5 7.2 1.5 5 25 20 0 6.5 7.2 1.5 5 25 30 0 6.5 7.2 1.5 5 25 40 47 5 5 3.5 1.5 3 50 71.6 4 5.5 2 2 4 60 80.6 3 5 3.5 -0.5 1 70 92.3 2 4.5 4 -2 4 80 100 1.5 4 4.5 3 9 90 101 1.5 4 4.5 3 9 100 102 1.5 3.3 5 -3.5 12.25 Total = 117.25 6?D2 rs = 1 - n(n2 - 1) From my spearmans rank analysis, I can see that Conclusions: From the results that I have collected from my investigation, I have come to the conclusion that my hypothesis is correct. From the results and graphs we can clearly see that as the distance from the sea increases, so does the pH of the soil, this then works in favour for Ling as it prefers acidic conditions and therefore the percentage cover of Ling increase. The humus content increases the more inland you go and this was evident since, the soil gradually went from a sandy colour to a dark brown colour. This humus content overlying the bare soil and plants contains various nutrients and microbes. These can cause for anaerobic conditions to form and hence therefore cause for the soil pH to decrease. Since the conditions of the soil are steadily becoming more acidic the pioneer species are being out-competed due to unfavourable conditions for the marram grass, therefore other species such as Ling Heather then become the more dominant until they completely out-compete other species. Explanation of Results: ...read more.

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