Peter and Kevin
October 28, 2010
Figure 2. Sign introducing Nose Hill. |
On September 20, 2010, my partner and I set off from Sir Winston Churchill High School to the wilderness of Nose hill Park. The wind was blowing after a large rainfall, we could still feel a light drizzle. Of course, we still went anyways. We prepared ourselves and entered Nose Hill’s vicinities.
Weary from our trip, we reach our destination. To our left were the vast grasslands; to our right was a dense forest. Of course, we knew ahead of time that the grasslands were our destination. We scaled the hill; our pants got wetter and wetter as we reach our target.
We examine the area and set up our simple 10 meter by 1 meter transect. Within the artificial boundaries of our transect was a myriad of life. At first glance, all one could see was grass; tall grass short grass, you name it. Some of these species include: snowberries, asters, wild roses, False Solomon’s Seals, and smooth bromes. With such a rich assortment of biodiversity, we hoped to uncover more about why so many plants can grow in our little transect.
After our initial observations, we decided to take some in-depth data. In the cold September weather, the temperatures at a meter above the ground were consistent 0.5°C. While temperatures 5 cm below the soil had respective temperature of -0.1°C, 0.0°C, 0.9°C, 0.0°C, and -0.2°C. The fact that temperatures beneath the ground were colder than temperatures above ground appalled us. We wondered why this would be. Perhaps, water was frozen beneath the ground, or maybe the soil is poor at retaining heat. We actually still can’t verify why this is.
Figure 4. the grass within our transect. |
Figure 6. A second soil correr sample. Our transect is in the background. |
Figure 5. Grassland soil core sample. |
To further examine our transect we took some soil samples using our soil corer. With limited success, we pulled up two samples. From our samples we could see that the just topsoil extended at least 20 centimeters. The soil from our samples was pretty consistent in their content. It had high humus content as well as decomposing organic matter, as well and some unrecompensed filler. We assumed that this soil composition provided a great abundance and verity of nutrients for the plant.
Figure 7. Soil characteristics and testing. |
The soils were tested by testing the possible nutrients that may have dissolved into distilled water after filtering a distilled water and soil mixture. Each nutrient was tested 5 times. The results were as follows. Ammonium had an average concentration of 2.6ppm, phosphates had an average of 0 ppm, iron had an average concentration of 0 ppm, Calcium had a average concentration of less than 20ppm, and nitrate had an average concentration of 2ppm.
Figure 8. Drawing of a Berlese funnel used to extract soil arthropods. |
Figure 9. Soil sample in the Berlese funnel. |
From these tests we could tell that two essential products from the process of nitrogen fixation and nitrification were present. Ammonium and nitrate are the basic essentials of plant growth. The abundance of these nutrients may explain the variety and abundance of plant life in these grasslands. However, we could not find existing data on the nutrient levels grassland soils so no comparisons could be made. Of course the decomposers like the earthworms probably helped the soil to get to this state. With so much plant life, the soil must depend on the decomposition of dead plants for its nutrients.
Water was found on average to make up 13.3 percent of the soils mass. This was done by finding the mass of 50g of soil after it was dried. The difference in mass must be the water that was evaporated. Organic material was also found to make up about 15.4 percent of the mass of the soil. Again, this was done by drying the soil, submerging it in water and collecting the debris that floats to the surface. The debris (organic material) is then dried and weighed again. Again, no reliable values could be found to compare this data. Therefore, it cannot be determined if a soil in this state is more beneficial or detrimental to plant growth. However, we can infer that this soil composition if beneficial due to the fact that there was such an abundance of producers in the ecosystem.
However, after two trials, only specs of dirt fell down the beaker. Perhaps our soils did not host as much life as we thought. Although, one has to consider that the soil was left in a Ziploc bag for a week.
Of course, there was more to our transect than just soil. To increase our understanding of the ecology of our transect. We gathered all the bio mass in a 0.25m2 area. Our dried producer biomass was 133.44g, our decomposer (a worm) biomass was 2.38g, and our consumer’s (an aphid and dwarf spider) biomass was 1.78g. In total this came to be 137.60g or biomass per 0.25m. According to this ratio, there should be 5504.00kg of biomass per hectare.
Figure 10. Arthropods on the Erlenmeyer flask after 24 hours in the Berlese funnel. |
Figure 11. Conversions of biomass to energy. |
We can also calculate that there are 40000 aphids, worms, and spiders per hectare of grasslands. However these calculations are likely to be completely inaccurate due the fact they are likely to be more consumers in our sample area but they were just too hard to spot.
In total there is 2386.21kj of energy per 0.25m2. According to this ratio, there is 95 448 400kjof energy per hectare.
From what we found in our transect, a food web can be produced as shown in figure 12.
From the species found in this web, we can only conclude the existence of interspecific and intraspecific competition and predation Various plant species compete other species for the space. This suggests interspecific competition. However these species also compete with other in their own species; suggesting intraspecific competition. Finally, aphids ingest the various producers and he spider eats the aphids. These are fine examples of predation.
Unfortunately, due to the lack of time and availability of species, this food web is likely a small fraction of the actual food web of the nose hill park grasslands.
And that concludes the part 1 of 3 part series on the ecology of the Nose Hill Park grasslands. We have observed many different species of plants and animals and found many quantitative relationships in our little transect. Tune to our podcast for the 2nd instalment of the Grassland Ecology of Nose Hill Park: The Transfer of Energy!
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