Abstract:
Aim: to investigate the spread of organisms across an ecosystem and how abiotic factors influence them.
Hypothesis: low light intensity can affect the rate grass grows which could lead to a lower grass coverage that could altogether lead to a lower population of Tapinoma sessile the population could also be affected by the surface (soil) temperature where warmer temperatures lead to a denser population.
Introduction:
the area that was studied was the Croft House picnic area (shown in figures 1 & 2) which is located directly out the front of Croft House. The collection of data was conducted over a 3-day period from Saturday the 24th of Feb to Sunday the 26th in the time-frame of 10:30 to 11:30 except on the last day when they were conducted from 11:45 to 12:35 due to outside interferences. The area contains a few large trees with a large amount of the sky being obstructed due to the high density of leaves and branches causing less light to pierce through to the ground. The area had an average light level (lux) of 0.8465 which can be used to explain the low amount of grass coverage in the area, which could have a further effect on the population of Tapinoma sessile in the area. There were also high average air and soil temperatures with the air being 23.2°C and the soil being 20.8°C, these warmer temperatures can additionally be linked to the population of T. sessile which like warmer weather conditions. There was also a fair amount of rainfall after the first day with it raining the afternoon and all night and then raining the next night along with when the third set of data was being collected the amount of rainfall could be used to explain the change in air temperature on the last day due to the vast amount of cloud coverage at the time.
Figure 2
Materials:
• 15m of rope
• 1x1m quadrat
• 1x note book
• 1x pen
• 1x multi-meter
• 1x soil temp probe
• 1x air temp probe
• 1x light level (Lux) probe
• a phone (for random number gen between 1-15)
• 1x 5m tape measure
Method:
Air temperature:
1. generate random number between 0-15 using mobile phone
2. walk however far the number says in meters along transect
3. place the quadrat roughly at your feet
4. turn on multi-meter and plug in air temperature probe
5. hold the probe roughly 1 meter above the ground and wait for the multi-meter to read an unchanging number
6. record the temperature in log book or on paper
7. repeat 4 more times
Soil temperature:
1. generate random number between 0-15 using mobile phone
2. walk however far the number says in meters along transect
3. place quadrat roughly at your feet
4. turn on multi-meter and plug in soil temperature probe
5. push the probe halfway into the ground (or as deep as possible) and wait for the multi-meter to read an unchanging number (might take 2-3 minutes)
6. record the soil temperature in log book or on paper
7. repeat 4 more times
Light intensity (Lux)
1. generate random number between 0-15 using mobile phone
2. walk however far the number says in meters along transect
3. place quadrat roughly at your feet
4. turn on multi-meter and plug in light intensity (Lux) probe
5. hold the probe roughly 1 meter above the ground and wait for the multi-meter to read an unchanging number (if you are under trees the number will continuously change and you’ll have to record a rough average based on the number range you see)
6. record the light intensity (Lux) in log book or on paper
7. repeat 4 more times
Ant population (Tapinoma sessile)
1. generate random number between 0-15 using mobile phone
2. walk however far the number says in meters along transect
3. place quadrat roughly at your feet
4. squat down and count as many ants as you can along with any other insects in the quadrat (also take note of any dead insects or food that may be attracting ants to that area
5. record all findings/results in log book or on paper
6. repeat 4 more times
Average Grass Coverage 1x1m
1. generate random number between 0-15 using mobile phone
2. walk however far the number says in meters along transect
3. place quadrat roughly at your feet
4. squat down and roughly figure out the average percentage of grass coverage in the 1x1m area
5. record average in log book or on paper
6. repeat 4 more times
Results:
Day 1 – Saturday the 24 of Feb – Weather sunny
Quadrat (1m2)
Air temp (°C)
Soil temp (°C)
Light Intensity
Grass Coverage (%)
Tapinoma sessile
Quadrat 1
24.1°C
23.0°C
0.9972
2%
7
Quadrat 2
23.6°C
21.4°C
0.9997
42%
12
Quadrat 3
23.5°C
20.1°C
0.9752
10%
5
Quadrat 4
24.0°C
20.1°C
0.4997
2%
1
Quadrat 5
24.3°C
20.8°C
0.9882
49%
8
Average
23.9°C
21.1°C
0.8920
20.8%
7
Day 2 – Sunday the 25 of Feb – Weather sunny with a bit of cloud coverage
Quadrat (1m2)
Air temp (°C)
Soil temp (°C)
Light Intensity
Grass Coverage (%)
Tapinoma sessile
Quadrat 1
23.9°C
20.5°C
0.8631
32%
8
Quadrat 2
23.9°C
20.7°C
0.9823
62%
11
Quadrat 3
24.0°C
20.7°C
0.9906
36%
9
Quadrat 4
23.9°C
20.6°C
0.3730
40%
18
Quadrat 5
24.0°C
20.7°C
0.5263
28%
6
Average
23.9°C
20.6°C
0.7471
39.6%
9
Day 3 – Monday the 26 of Feb – Weather cloudy and raining
Quadrat (1m2)
Air temp (°C)
Soil temp (°C)
Light Intensity
Grass Coverage (%)
Tapinoma sessile
Quadrat 1
22.1°C
21.6°C
0.9732
70%
2
Quadrat 2
21.6°C
20.8°C
0.9235
57%
5
Quadrat 3
22.6°C
20.0°C
0.9997
42%
8
Quadrat 4
21.2°C
21.4°C
0.9696
86%
2
Quadrat 5
21.3°C
20.2°C
0.6354
8%
0
Average
21.8°C
20.8°C
0.9003
52.6%
3
Discussion:
The area studied consisted of higher temperatures of both soil and air this is due to the time the measurements were taken which was roughly around mid-day when the temperature reaches/starts to peak, additionally this would have also influenced the lux reading possibly raising it due to the sun being at a more central point in the sky though this can’t be said for the last day due to the high amount of cloud coverage there was. The density of grass in the area was quite low in some areas and this can be related to the high density of leaves and branches on the trees above blocking light, with only a small amount piercing through, this causes the area to stay muddier for longer and since it’s a common area that a reasonable people walk through probably lead to most the grass being trampled into the mud. The population of Tapinoma sessile as a species can be heavily influenced by the amount of grass coverage due to it being required to allow same travel for them so they can avoid predators along with there possibly being more insects thriving in the grass that could be a food source or prey.
In the ecosystem studied, there are some clear relationships between biotic and abiotic factors, the ones that can be clearly observed are the light intensity on the grass coverage and the temperatures on the ants. The impact that the light intensity had on the grass coverage was that it seemed to cause less grass to grow in the areas with less light from the sun this is believed to be because grass produces its nutrients and lives through the process of photo synthesis and since there was less access to sunlight in these areas grass couldn’t grow because it couldn’t photosynthesize, this is similar for the brown grass in the area that gets plenty of sunlight but can’t photosynthesize due to it not containing enough chlorophyll which enables the process of photosynthesis. On the other hand, the air and soil temperatures don’t impact the Tapinoma sessile species much at all due to them having a great ecological tolerance that beats almost all other species of insects or ants.
When the study of the Tapinoma sessile species was being carried out there were signs of one predator which were the Australian magpie which feed on small insects that live underneath the surface.
Reference list:
https://www.thelawninstitute.org/pages/education/grass-plant-physiology/photosynthesis/