Ellice Wakelin

Investigating the effects of trampling on ribwort plantain (Plantago lanceolata).

ContentsAbstract.................................................................................................................................................1

Aim........................................................................................................................................................1

Hypothesis.............................................................................................................................................2

Rationale...............................................................................................................................................2

Risk assessment.....................................................................................................................................4

Strategy.................................................................................................................................................5

Trial runs................................................................................................................................................6

Method................................................................................................................................................12

Final data.............................................................................................................................................15

Modifications.......................................................................................................................................19

Analysis................................................................................................................................................20

Evaluation............................................................................................................................................22

Conclusion...........................................................................................................................................22

Bibliography.........................................................................................................................................22

AbstractThis investigation was carried out at Slapton Ley national nature reserve on the shingle ridge in early October to investigate the effects of trampling on the growth of P. lanceolata. The plant growth was measured by the length of the leaves after discovering that there was a strong correlation between leaf length and leaf biomass. The plant growth was measured in a heavily trampled area on the shingle ridge and an exclosure plot that is fenced off from public access so has had very little trampling. The results showed that P. lanceolata leaves were significantly longer in the non-trampled area, supporting the hypothesis.

AimThe aim of this report is to investigate how trampling affects plant growth, by taking data from a heavily trampled area and an area of minimal trampling. Trampling damages the plants and causes soil compaction which could affect the plants and their growth.

Hypothesis

1

Ellice Wakelin

There will be a significant difference in the growth of P. lanceolata, measured by leaf length, between a trampled and a non-trampled area, measured by soil compaction. The plant growth will be higher in the non-trampled area.

Rationale In 2003, on the shingle ridge 4 exclosure plots (grid reference: SX829440 [1]) were established for research purposes, this is where the investigation was carried out.

The shingle ridge at Slapton Ley National Nature Reserve is 3.5km long and separates the Slapton Ley, a freshwater lake, from the sea[2]. The shingle provides a very unstable environment; it greatly lacks in nutrients and doesn’t hold water very well. Plants will not be found low down on the beach where the tide will wash over them as it is too regularly disturbed. Further up the beach, past the tide line, some plants have started to grow. These are pioneer species, they have to be well adapted to the harsh conditions so close to the sea, for example they have very waxy leaves to prevent them from losing too much water. Further up the shore where these pioneer species have been able to grow for a longer period of time and have formed a thin layer of soil. Plants at this level still have to be able to survive with low nutrient levels and little water as the soil is only a thin layer. This process continues further up the shingle ridge and is called succession.

Slapton Ley is a National Nature Reserve (NNR) and a Site of Special Scientific Interest (SSSI) therefore conservation and management of organisms is important. This also means that there are a large amount of people who come to visit, both scientists and tourists, hence there is a lot of trampling because so many people visit.

Trampling can create many problems for plants, for example:

Physical damage to plants by removal of growing tips and crushing occurs. Damage may also reduce flowering. Trampling, like mowing, results in different heights of vegetation so competition for light

might be a factor. Deposition of litter and dog fouling may cause changes in the soil mineral content though

any change is difficult to measure without sophisticated equipment[3].

Figure 1. Showing how soil compaction can affect plant growth[3].

Figure 1 shows some additional factors that soil compaction creates that can reduce plant growth, and further support the hypothesis.

2

Ellice Wakelin

P. lanceolata was chosen over other plants because it is very abundant. This is good because it means that the destruction that I cause will have a smaller overall impact because there is a larger population and it is not a rare plant. Also, being more abundant, it will give more valid and accurate results, this is because there are more plants available to measure in the area, this will allow for a larger sample size which will provide more accurate data because any anomalies will have a smaller effect on the overall result. P. lanceolata is also easily identifiable; it has spear-shaped leaves which form a rosette at the base of the plant. Short stems grow from its leaves, with compact heads and protruding, white stamens. The flower heads gradually turn brown and seed [4]. P. lanceolata is pictured below in figure 2.

Ribwort plantain (P. lanceolata) is less well adapted to heavily trampled sites. It is less tolerant to physical damage and is less likely to grow in waterlogged soil[3]. This also supports my hypothesis because it implies that P. lanceolata is not able to grow as well in trampled sites, and therefore should have poorer growth resulting in smaller leaves.

Results may indicate how trampling has an effect on the growth of plants such as P. lanceolata and whether we should have more areas that are closed off from frequent trampling to promote the growth of plants that are not as well adapted to soil compactness and the other factors that stem from trampling, especially as the shingle ridge is quite an unstable environment already. Also, Slapton is a NNR and SSSI which means that management and protection of the organisms is important. Furthermore, P. lanceolata is also used for medicinal purposes so knowing how it is affected by trampling would be useful for determining conditions for efficient growth and also to prevent the plant growing smaller and becoming less useful.

3

Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].Figure 2. Ribwort plantain (Plantago lanceolata)[5].

Ellice Wakelin

Risk assessmentHazard Risk Likelihood

1=unlikely2=small possibility3=quite likely4=likely5=very likely

Severity1= very minor injuries (small scratches and bruises)2=not very severe (eg. larger cuts)3=quite severe (eg. Cuts or other minor injuries that would need medical attention)4=very severe (eg. broken bones)5=possible risk of death

Overall risk (likelihood x severity)

Precaution

RoadsA379 – main road

Being hit by a car

1 5 5 Fluorescent jacketsStaying in groupsTaking care when working near or crossing the road.

Fenced exclosure plots

Tripping over when stepping over the wire fence

2 2 4 Be careful when climbing over the fence, don’t be too hasty

Uneven ground

Slips, trips and falls

3 2 6 Wear suitable footwear.Take care

Sharp and stinging plants

Cuts, pricks and stings

3 1 3 Wear long clothes and be aware of the plants you are around specifically in long vegetation.

Hot crucibles after cooking soil samples in the ovens

Burns 2 2 4 Leave the samples to cool down for a while after

4

Ellice Wakelin

being in the oven.

Hammering in the infiltration ring

Hitting self with the hammer

1 2 2 Take care when using the hammer.

Weather (Rain)

Slipping on wet shingle

1Weather forecast

shows that it is unlikely to

rain

2 2 Wear suitable footwear and take care when walking on slippery surfaces

The overall risk is out of 25. A result of 25 would most definitely be too dangerous to consider going out into the field. A result of an overall risk of over 12 may be too risky and the method would have to be reconsidered.

I also need to consider some of the ethics involved in this investigation. I will need to take care to cause as little disturbance to the ecosystem as possible, as being very destructive could cause harm to the whole ecosystem because all the organisms are interdependent.

StrategyThe abiotic factor that I will be changing is the amount of trampling. This would be impossible to directly measure because it is constantly changing as people continue to walk over the area, making it very hard to obtain a valid measurement. A measure of trampling would be made by finding the average force per unit of time per unit area; this would involve knowing the amount of people walking over the area and their weights. However, even if I could get this data, it would still not be accurate because every person walks differently exerting a different force on the ground, despite their mass. Therefore, I will need to find a different way to measure the amount of trampling and I think the best way to do this is by measuring soil compactness, because soil compaction is a major effect of trampling[3]. I could do this with an infiltration device, or the pin drop method.

My dependent variable will be plant growth; I have chosen to use a calibration curve of leaf biomass against leaf length to measure this. Measuring the whole plant biomass would have been more accurate, because it accounts for all the growth of the plant, both visible and invisible from above ground. However I had to consider the damage to the environment that removing whole plants would have, especially as the areas I am working in are used for a lot of other research

Trial runsQuestions

5

Ellice Wakelin

What would be the best way to measure the plant growth?As previously discussed, plant biomass would be the best measure of plant growth, however I have established that this would not be ethically feasible as it is far too destructive to the environment that I am working in.Leaf biomass is an accurate and reliable way of showing plant growth because it is an accurate measure of the whole leaf. However it is an ethical limitation of this method is that it is very destructive to the plants, especially when large numbers of people are doing similar investigations constantly. Furthermore, I was working in an exclosure plot which is used in many investigations to look at how the plants would grow without disturbance from humans; therefore it is important that I cause as little disturbance as possible while taking my measurements. Also, measuring the biomass of leaves also has practical limitations such as it is very time consuming as they need to be dried in the oven for a few hours, which is also a problem because the centre have limited space in the oven, so measuring the biomass of each leaf would not be feasible. Therefore I will not be measuring the biomass of whole plants or measuring the biomass of each leaf I need to measure. So I need to find another method that will provide me with data that is also accurate and reliable but with fewer ethical and practical limitations. Looking at the P. lanceolata plants there is a significant correlation between the length of the leaves and the size of the plant. If I can show that there is a significant correlation between the leaf biomass and the leaf length by plotting a calibration curve, then I can use leaf length to measure the plant growth, as it isn’t harmful to the plants and it is a lot quicker to measure. A strong correlation has a value very close to 1, which is how I will know if the correlation is significant enough to use.The correlation curve needs to be representative of the whole area, therefore I will need measurements from the shortest leaves to the longest leaves and a good spread of lengths inbetween.

The calibration curve shows a strong positive correlation with an R2 value of 0.9798 which is very close to 1 and therefore shows a significant correlation. Therefore, as I have shown a significant correlation between leaf length and biomass, I can use leaf length as a measure of growth in my main investigation.Using this graph I can calculate the leaf biomass from the leaf leaf length that I measure during the final investigation.

6

Graph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomassGraph 1. Calibration curve showing the relationship between leaf length and leaf biomass

Ellice Wakelin

What is the best method to measure soil compaction?One possible method to measure soil compactness is using a penetrometer, however this is not always very accurate as it can be easily affected by stones to give unreliable data and as I am working on the shingle ridge where there will be many stones, I do not think this would give the most accurate data. A second method is constant head infiltrometry however this is very time consuming which makes it hard to get enough data, also in my trial run I found a lot of the equipment was leaking and it didn’t work very well in the shingle. Therefore, I chose to use the infiltrometer ring. I filled it with water and timed how long it took for all the water to be absorbed into the ground. I made sure that the ring was the same depth in the ground every time so that there was the same volume of water draining into the ground for each measurement.

To calculate the infiltration rate I need to know the volume of water that I put in each time, this can be easily calculated using the diameter (d) and height (h)of the ring and using the equation:

V=π ( d2 )2

h

Diameter = 10.5cm

Height = 16.2 – 5.0cm = 11.2cm

Volume = 969.81 cm3

Then to calculate the infiltration rate you divide the volume by the time taken for the water to infiltrate into the soil. This is a table of my results from the trial run:

Inside exclosure plot Outside exclosure plotTime (s) Rate (cm3s-1) Time (s) Rate (cm3s-1)34.35 28.23 63.91 15.1726.17 37.06 54.82 17.6935.29 27.48 68.78 14.1039.97 24.26 74.59 13.00

What abiotic factors will I need to measure and take into consideration tomorrow?

In this investigation I needed to ensure that I was actually measuring the effect of soil compactness on the growth of P. lanceolata, and that there were not any other confounding factors that were affecting the growth. I know that there is no reason why the light intensity should be different as there is no canopy over either plot, and they are at the same height above sea level, same aspect and very close together, therefore I can eliminate light intensity as a factor because it does not vary enough between the two plots to have any effect on my measurements, I am also eliminating wind velocity for the same reasons. I can also eliminate soil pH because plantain occurs naturally over a wide range of soil acidity (pH 4.2–7.8)[6], and there is also no reason why the pH’s should differ between the two areas as they are so similar. Finally, I will also not need to measure soil temperature because it will not have an impact on my results, and it should be very similar between the two plots because they are getting the same light intensity, they are the same distance from the sea and so they shouldn’t differ.

7

Table 1. Table to show the infiltration rates of the soil in both areas

Ellice Wakelin

Soil depth

My research shows that plantain is capable of utilising nutrients from deeper soil layers [6], which implies that soil depth could be a factor that would affect the growth of plantain which is why I will be measuring it, to see if there is a difference between the two areas because if it can’t be controlled then it needs to be measured and taken into account.

For soil depth I will take a running mean, so that if my results show that there is a difference in soil depth between the exclosure plot and outside the exclosure plot then I will know how many measurements I will need to take in my main method to obtain a representative sample of the soil depth in that area for more accurate results.

To measure soil depth I used a pin from a point frame quadrat and pushed it into the ground until I felt an increase in resistance and found it hard to push the pin in further, I then placed my index finger and thumb at the point on the pin that is just above the ground and pulled it out. Using a ruler, I measured the length of the pin from the end to my finger and thumb.

8

Graph 2. Box and Whisker plot showing the difference in soil depth between the two areas.

Depth (cm)

Inside the exclosure plot Outside the exclosure plotSample number

Soil depth (cm)

Running total

Running mean

Sample number

Soil depth (cm)

Running total

Running mean

1 8.1 8.1 8.10 1 3.9 3.9 3.902 8.3 16.4 8.20 2 5.4 9.3 4.653 7.9 24.3 8.10 3 4.3 13.6 4.534 6.8 31.1 7.78 4 5.6 19.2 4.805 5.9 37.0 7.4 5 4.6 23.8 4.766 5.8 42.8 7.13 6 4.1 27.9 4.657 6.5 49.3 7.04 7 5.3 33.2 4.748 7.4 56.7 7.09 8 4.7 37.9 4.749 7.0 63.7 7.08 9 4.5 42.4 4.71Table 2. Table to show the running mean of the soil depth in both areas.

Ellice Wakelin

This box and whisker plot (graph 2) shows a difference in soil depth between the two areas. This could be a result of more plant growth in the non-trampled area, and therefore a faster development of soil. However, this could be a confounding factor as there is no proof that it is caused by a higher plant growth and not that it causes a higher plant growth.

This abiotic factor will need to be measured in the final method and due to the result of my running mean I will make 6 measurements from each area.

Soil moisture

To measure the soil moisture content I took soil samples from inside and outside the exclosure plot, making sure that the tubes were labelled to avoid mixing them up. I used a trowel to dig up some soil and filled up a soil sample pot. Back at the centre, I collected some crucibles. Then for each sample, I weighed the empty crucible and then put the soil sample into the crucible and label it with a pencil and weigh the mass of the crucible and wet mass, I then repeated this for each sample. I put all the samples into an oven at about 110°C for about 2 hours so that all the water is evaporated. When the samples have cooled enough to be handled, I re-weighed each crucible and the dry mass of soil. Then I used the formula:

soilmoisture (%)=w−dw−c

×100%

(Where w is the wet mass of the soil in the crucible and d is the dry mass in the crucible and c is the mass of the crucible.)

I have taken a running mean of the soil moisture (table 3) to find out both whether there is a difference in the moisture content between the two areas and also to decide on the sample size if I need to measure it in my final method.

Inside the exclosure plot Outside the exclosure plotSample number

Soil moisture (%)

Running total

Running mean

Sample number

Soil moisture (%)

Running total

Running mean

1 2.27 2.27 2.27 1 1.62 1.62 1.622 1.53 3.80 1.90 2 4.01 5.63 2.823 5.41 9.21 3.07 3 0.27 5.90 1.974 9.96 19.17 4.79 4 2.47 8.37 2.095 1.66 20.83 4.17 5 1.89 10.26 2.056 2.69 23.52 3.92 6 4.16 14.42 2.40

Soil organic matter

After weighing the dry mass of the soil (as done previously when measuring the soil moisture content), put the crucibles into an oven at 400°C for about 4 hours. When the samples come

9

Table 3. Table to show the percentage soil moisture in both areas

Ellice Wakelin

out of the oven, take a measurement of the burnt mass. This mass will be all the inorganic matter, because the organic matter has all been burnt off. Then calculate the percentage organic matter using this equation:

organic matter (% )=d−bd−c

×100%

(Where b is the mass of the burnt soil and the crucible, d is the mass of the dry soild and crucible and c is the mass of the crucible.)

Inside the exclosure plot Outside the exclosure plotSample number

Soil organic matter (%)

Running total

Running mean

Sample number

Soil organic matter (%)

Running total

Running mean

1 2.12 2.12 2.12 1 0.68 0.68 0.682 2.72 4.84 2.42 2 6.41 7.09 3.553 10.04 14.88 4.96 3 0.43 7.52 2.514 3.73 18.61 4.65 4 3.30 10.82 2.715 2.48 21.09 4.22 5 10.29 21.11 4.226 3.69 24.78 2.75 6 0.76 21.87 2.43

10

Table 4. Table to show the percentage organic matter of the soil in both areas

Soil organic matter content (%)

Graph 3. Box and whisker plot showing the difference in organic matter content between the two areas

Ellice Wakelin

This data, as shown in graph 3, shows a complete overlap in the two sets of data, showing no significant difference in organic matter content, so I can be confident that organic matter will not be affecting my results.

Sampling strategy?I will use random stratified sampling because I am comparing two uniform areas and I will need representative samples from each area.I will use a 10m2 grid because I need a representative sample of the area, and a smaller quadrat would not allow for that, and a larger quadrat would not fit into the exclosure zone and it would also be unnecessarily large. I will generate random numbers using my calculator to randomly select co-ordinates where I will take my measurement from; I will do this to remove bias from my results to make them more reliable.

Sample size?I took a running mean of the leaf lengths in each area to find out how many samples I would need to take in my actual investigation. Also taking into account that I will be using the t-test which requires a minimum of 15 measurements, so as long as the running mean evens out at less than 15 samples, then my sample size is dependent on the stats test.

Inside exclosure plot Outside exclosure plotSample number

Leaf length

Running total

Running mean

Sample number

Leaf length

Running total

Running mean

1 13.4 13.4 13.4 1 12.1 12.1 12.12 13.9 27.3 13.65 2 14.5 26.6 13.33 11.6 38.9 12.97 3 11.0 37.6 12.534 19.6 58.5 14.63 4 12.4 50.0 12.55 17.9 76.4 15.28 5 9.8 59.8 11.966 13.1 89.5 14.92 6 10.3 70.1 11.687 11.8 101.3 14.47 7 7.6 77.7 11.08 11.2 112.5 14.06 8 8.1 85.8 10.739 18.3 130.8 14.53 9 9.3 95.1 10.5710 17.5 148.3 14.83 10 10.2 106.3 10.63

The running mean shows that a sample size of 10 is sufficient to provide a representative sample. However, at least 15 measurements need to be taken for the t test, and also the stats tests become more reliable with larger sample sizes so, in this investigation, at least 20 measurements will be made from each area, and possibly more depending on the time available.

MethodEquipment

2x 10m Tape measures Metre ruler Callipers

11

Table 5. Table to show a running mean of leaf lengths

Ellice Wakelin

Infiltration meter ring Hammer Permanent marker Bottles of water Soil pin 12 x Soil sample pots Trowel Weighing scales Oven at 110 degrees 12 x Crucibles

1. Arrive at the shingle ridge exclosure plots (grid reference: SX829440[1]). There are 4 exclosure plots as shown in figure 3 below, and the third one (from the Northern direction) was used in this investigation because P. lanceolata was most abundant here which made it easier to take a large sample of measurements to make data more accurate.

2. Set up a 10m x 10m quadrat in the exclosure zone and one outside the exclosure zone. The one outside the exclosure zone should be about 1m away from the fence, because trampling around the fence will be low.

3. As a quantitative measure of soil compaction, record the soil infiltration rates inside and outside of the exclosure plot. To do this, generate two random numbers between 0 and 10

12

Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].Figure 3. A map of the shingle ridge with the exclosure plots marked and the one used marked in red[7].

Ellice Wakelin

using Ran# x 10 on your calculator, the first number being your x co-ordinate and the second being the y co-ordinate. In this position, hammer the infiltration ring into the ground about 5cm (figure 4), and using a permanent marker, mark where the ground comes up to on the ring. Fill up the infiltration ring with water and measure the time it takes for all the water to

be soaked into the ground. Repeat this again so that you get 15 measurements for inside and outside the exclosure plots. Use the marker line to determine how far in you need to

hammer the ring each time, as the volume needs to remain constant each time for accurate results. Then measure the inside diameter and height (from the marked line) of the

infiltration ring. Then use this to calculate the volume of water in the ring each time with the equation:

V=π ¿ (with d being the diameter and h being the height.) Now divide the volume by time taken for the water to drain, and this will give you the infiltration rate. Do this for each

result.

4. Measure soil moisture content. Using random co-ordinates again, take 6 soil samples from inside the exclosure plot and 6 from outside (6 samples was decided from the running mean in the trial investigation). To do this, use a trowel to dig up some soil from that point in the quadrat and fill up a soil sample pot. Repeat for each co-ordinate. When you get back to the centre, collect 12 crucibles and label the sample number on them with a pencil. Weigh the crucible, pour in the soil and weigh the mass of the crucible and wet mass, do this for each sample. Put all the samples into an oven at about 110°C for about 2 hours so that all the water is evaporated. When the samples have cooled enough to be handled, re-weigh each crucible and the dry mass of soil. You can then use the formula:

13

Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)Figure 4. The infiltration ring being hammered into the ground. (Own photo)

Ellice Wakelin

soilmoisture (%)=w−dw−c

×100%

(where w is the wet mass of the soil in the crucible and d is the dry mass in the crucible and c is the mass of the crucible.)

5. Measure the soil depth. Generate random co-ordinates with your calculator and go to that point, push a pin from a point frame quadrat until you feel a larger resistance, place your finger and thumb at the point on the pin that is just above the ground and pull it out. Using a ruler, measure the length of the pin from the end to your finger and thumb.

6. Next measure the leaf lengths of some P. lanceolata plants. Using generated co-ordinates, locate a point in the quadrat inside the exclosure plot. When you have located the plant, measure the length of the longest leaf with some callipers. Repeat this to get 20 results inside and then repeat outside the exclosure zone to avoid only getting enough results in

one of the areas, and if there is time after this then repeat to get more data.

Final dataPlant Gowth

Sample number Inside exclosure plot Outside exclosure plotLeaf length (mm)

Leaf biomass (g)

Leaf length (mm)

Leaf biomass (g)

14

Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)Figure 5. Measuring the leaf length with callipers. (Own photo)

Ellice Wakelin

1 118 0.13 129*2 0.152 139 0.16 91 0.093 105 0.11 94 0.104 152 0.18 82 0.085 86*1 0.08 65 0.056 126 0.14 86 0.087 109 0.12 71 0.068 114 0.12 103 0.119 119 0.13 79 0.0710 112 0.12 74 0.0711 147 0.17 64 0.0512 151 0.18 53 0.0313 111 0.12 96 0.1014 149 0.18 85 0.0815 155 0.19 109*3 0.1216 180 0.22 103 0.1117 122 0.14 101 0.1118 124 0.14 92 0.0919 146 0.17 89 0.0920 143 0.17 90 0.0921 131 0.15 87 0.0822 137 0.16 91 0.0923 125 0.14 59 0.0424 148 0.17 67 0.0625 150 0.18 93 0.0926 132 0.15 62 0.0527 146 0.17 57 0.0428 151 0.18 61 0.0529 141 0.16 102 0.1130 176 0.22 88 0.09

*1 in very shingley patch

*2 under large vegetation

*3 amongst many other plants

Anomalies

Three of my measurements were noticeably different from the others and after I made them I checked again to make sure I hadn’t made an error in measuring them. They were also in slightly different conditions to the rest of the samples. However, in analysing the data I collected using box and whisker plots, I have found that these results are not identified as anomalies because they are not more than 1.5 times the interquartile range away from the first or third quartiles. Therefore I have kept these results in my analysis to keep a fair and representative sample of the two areas.

15

Table 6. Table to show final data for leaf length and calculated leaf biomass in the two areas.

Ellice Wakelin

Soil infiltration rates

Vol = 969.81 cm3

Inside exclosure plot Outside exclosure plotTime (s) Rate (cm3s-1) Time (s) Rate (cm3s-1)40.37 24.02 124.20 7.8151.79 18.73 61.39 15.8044.67 21.71 90.14 10.7629.40 32.99 86.21 11.2561.69* 15.72 75.88 12.7827.41 35.38 109.26 8.8832.74 29.62 50.23* 19.3149.91 19.43 98.34 9.8637.45 25.90 87.29 11.1148.32 20.07 72.17 13.4447.39 20.46 102.84 9.4339.16 24.77 99.79 9.7233.84 28.66 115.64 8.3927.33 35.49 89.74 10.81

16

Graph 4. Box and whisker plot showing the difference in leaf lengths between inside and outside of the exclosure plot

Leaf length (mm)

Ellice Wakelin

32.59 29.76 78.03 12.43Mean 25.51 10.89

Graph 5 shows that there is a difference in soil infiltration rate between the two areas, which therefore shows that the area outside the exclosure plot is actually more trampled than inside the exclosure plot. Therefore the results of this investigation will be valid.

Graph 5 also supports that the rate of 19.31 is an anomalous value therefore I will not use it when calculating the mean infiltration rate.

Abiotic factors

Soil depth (cm)Inside exclosure plot Outside exclosure plot13.4 5.716.7 8.613.6 5.116.1 6.913.6 9.315.3 7.8

Mean 14.8 7.2

17

Soil infiltration rate (cm3s-1)

Graph 5. Box and whisker plot to show the difference in soil infiltration rate between the two areas.

Table 7. Table to show the final data for infiltration rates of the soil in both areas

*measurement was taken on a very loose shingley patch

Ellice Wakelin

Inside exclosure plot Outside exclosure plotSample number

Mass of crucible

Wet mass

Dry mass

% moisture

Sample number

Mass of crucible

Wet mass

Dry mass

% moisture

1 19.53 34.98 34.63 2.27 1 19.95 45.24 44.83 1.622 20.51 36.21 35.97 1.53 2 16.97 28.68 28.21 4.013 19.42 27.00 26.59 5.41 3 19.00 44.87 44.80 0.274 18.62 35.59 33.90 9.96 4 18.05 31.41 31.08 2.475 19.32 30.79 30.60 1.66 5 18.04 36.57 36.22 1.896 17.51 28.65 28.35 2.69 6 17.13 25.30 25.02 3.42mean 3.92 Mean 2.28

Modifications

As I was doing the investigation, I found that there wasn’t always a P. lanceolata plant right on my generated co-ordinate. Therefore, to continue to prevent bias, if there was not a plant on that spot, then I would hold out a metre ruler and face north, and turn clockwise until I located a plant. If there was not a P. lanceolata plant within a 1 metre radius then I would generate some new co-ordinates and repeat.

A second thing that I found when taking measurements was that it was not usually immediately obvious which leaf on the plant was the longest, therefore I would have to measure a few leaves to decide which one was the longest before recording my measurement.

18

Table 8. Table to show the final data for soil depth in the two areas

Table 9. Table to show the final data for percentage moisture content in the soil in the two areas

Ellice Wakelin

Analysis

Null hypothesis: There will be no significant difference in leaf length between the trampled and non-trampled areas.

The T test returned a result of 9.701 which is greater than the critical value of 2.009 at the 5% significance level. This means that the null hypothesis can be rejected indicating that there is a significant difference in leaf length between a trampled and a non-trampled area. The test statistic is also higher than the critical value at the 1% significance level which shows that there is a highly significant difference.

The soil was deeper inside the exclosure plot than outside; the mean soil depth was 14.8cm inside the exclosure plot which is more than double the soil depth outside the exclosure plot which was 7.2cm. The soil moisture is also higher in the exclosure plot; there is a percentage difference of 72% between the two areas.

19

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Figure 6. A screenshot of the T-test for my dataWhere x1 = inside the exclosure plotAnd y1 = outside the exclosure plot

Ellice Wakelin

I think that the reason for the significant difference in plant growth between the trampled and non-trampled area is the soil compaction and not the soil depth or organic matter content. This is because, a larger plant growth would result in more organic material being put into the soil by a larger amount of decomposing plants and this is also what results in the deeper soil, because there are more decomposing organisms making up the soil. This, in turn would also result in higher plant growth because there are more nutrients available to the plant, promoting faster growth.

The process of succession is happening on the shingle ridge, so the vegetation increases in size as you move further inland. Figure 7 shows the seres at certain points up the ridge; these are different communities of plants. The species closest to the shore are the ones that are very well adapted to the extreme conditions of the shore, such as a lack of organic matter, nutrients and water. P. lanceolata is part of the meadow community; therefore it is not quite as well adapted to a lack of water and nutrients as the pioneer and maritime specialist plants.

Trampling damages pastures by causing soil compaction and puddling — where air or waterfilled pore spaces are replaced in the soil, restricting oxygen to plant’s roots. Trampling depresses fertilizer and water movement in the soil, nitrogen fixation is reduced and root growth is impeded [8]. This explains how trampling can lead to poorer growth in plants, because they have less oxygen, less nutrients and nitrogen fixation, less water and also, if root growth is impeded then this further restricts the access that the plant has to water and nutrients. This is a problem for the P. lanceolata on the shingle ridge as there is a large amount of competition between plants and as there is already a lack of nutrients, good root growth is necessary to outcompete other plants and survive.

Compaction of the soil reduces pore size and therefore reduces air infiltration; this prevents the roots from getting enough oxygen for respiration. Beneficial soil organisms also don’t get enough

20

Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].Figure 7. Photograph of the shingle ridge illustrating the change in vegetative communities as a result of succession[2].

Ellice Wakelin

oxygen and they die, preventing the plant from getting enough nutrients from the soil [8]. This will stunt growth, resulting in smaller plants.

EvaluationOne limitation of this experiment is that it was only conducted in one area. This means that, firstly there is only one set of data, and the hypothesis would be a lot better supported if this result was shown to be repeatable in other areas. Secondly it means that the investigation has a limited scope which may affect the reliability of the conclusion. To improve this, some additional investigations should take place to prove that the result is repeatable.

Another limitation is that the method used for measuring compactness was not as accurate as it could have been, because although I tried to keep the infiltration ring in the exact same depth each time to make sure the same volume of water was used each time, it wasn’t the best method to use. A better method would have been to use a smaller bottle of a known volume (less than that of the capacity of the ring), fill that up completely with water and pour it into the ring and time it.

One more limitation of this experiment is that I was not able to measure biomass of entire plants for practical and ethical reasons. This was a problem because a lot of the plant growth is in the roots, which I was unable to measure. If this investigation were to be made more accurate, it would be much more accurate to grow the plants in these conditions for a certain amount of time and then to measure the whole plant biomasses and compare them. This would give much more accurate data because it is taking into account the whole plant and there are very small degrees of error in weighing when you have very precise scales.

ConclusionThe results of this investigation support the hypothesis that the leaf lengths of P. lanceolata will be significantly longer in the exclosure plots with very minimal trampling than in the heavily trampled area. Therefore the results also support the theory that trampling has an effect on the growth of P. lanceolata.

I think my results are fairly reliable because I researched how P. lanceolata would be affected by some of the other abiotic factors, and the ones I thought could also affect the growth were monitored and accounted for. Although the limitations discussed in the evaluation may affect the reliability of my results.

However, I am confident in my conclusion because the statistical test showed a very significant difference supporting the hypothesis and there are biological principles that can support my conclusion, increasing my confidence in it.

Bibliography

[1] Shingle Ridge, working information card - Field Studies council: http://www.field-studies-council.org/media/727108/shingle_ridge_working_information_card.pdf [Accessed 15.10.2014]

21

Ellice Wakelin

[2] Shingle Ridge – Slapton Ley National Nature Reserve: http://www.slnnr.org.uk/wildlife/habitats-conservation/shingle-ridge.aspx [Accessed 15.10.2014]

[3] The effects of trampling – Field Studies Council: http://www.field-studies-council.org/urbaneco/urbaneco/grassland/trampling.htm [Accessed 6.10.2014]

[4] Ribwort Plantain – The Wildlife Trusts: http://www.wildlifetrusts.org/species/ribwort-plantain [Accessed 15.10.2014]

[5] Plantago lanceolata – Plant Identification, West Highland Flora (Farmer, C): http://www.plant-identification.co.uk/skye/plantaginaceae/plantago-lanceolata.htm [Accessed 12.11.2014]

[6] Plantain (Plantago lanceolata) – a potential pasture species – New Zealand Grassland Asociation 58; Stewart, A (1996); Christchurch

[7] Pasture Improvement: Trampling Effects – Ontario Ministry of Agriculture, Food and Rural Affairs: http://www.omafra.gov.on.ca/english/crops/pub19/3trampfx.htm#table34 [Accessed 21.10.2014]

[8] How Soil Compaction Affects the Growth of Plants – SF Gate (Waterworth, K): http://homeguides.sfgate.com/soil-compaction-affects-growth-plants-40867.html [Accessed 12.11.2014]

The sources 1 and 3 from the Field Studies Council and source 2 from Slapton Ley National Nature Reserve were chosen for their reliability because they are written by the organisations that run the Slapton Ley centre therefore they will be able to provide reliable and accurate data, and they are also an educational organisation so their information should be unbiased and purely factual.

Source 4 by The Wildlife Trusts provided a brief description of the appearance of P. lanceolata. I believe that they provide reliable information because they are a charity that works to protect wildlife so they are experienced in studying these organisms and would be able to provide a reliable description of the plant.

Source 5 from the plant identification website provided some good pictures of P. lanceolata. It does not provide much information except a very brief description of the plant, however I consider it to provide accurate pictures, and they are all referenced and copyrighted with a date and name.

The report by A. Stewart (source 6) provided a reliable source as it is published in ‘Proceedings of the New Zealand Grassland Association 58’ and these reports are peer reviewed which shows that it must be very reliable because other credible scientists have checked the principles and agree with them because it was published. The organisation ‘New Zealand Grassland Association’ also hold annual conferences in New Zealand where professionals will discuss many agricultural topics which shows great credibility in the wider community as these publications come from a very professional and scientific organisation.

Source 7 from Ontario Management of Agriculture, Food and Rural affairs (OMAFRA) should be reliable because it is a government organisation and they are providing factual information about how soil compaction can affect crop growth to inform and help farmers in their community. Therefore it will be credible because the government will be able to get information and data from

22

Ellice Wakelin

leading scientists and they are providing information to help improve their economy, therefore it is in their interest for their information to be accurate.

The article from SF Gate (source 8) about how soil compaction affects the growth of plants provided useful information on the effects of soil compactness. I think this source is reliable because it is a well know news site, and this article was in the home section and was based on gardening. Although the author is not a credible scientist, the news site would want to give reliable information in order to keep their audience; therefore I think the author would have done a significant amount of research so that they knew the information they were writing was accurate.

23