Monday, November 28, 2011

A day at the Pond, by Jeff and Liz

On September 22, 2011, the students of Sir Winston Churchill High School’s Bio 20 IB went on an expedition to Nose Hill Park in Calgary, Southern Alberta to observe and record data about the exciting ecosystems. Nose Hill Park is a man-preserved environmental area located in the North West quadrant, situated between John Laurie Blvd and Shaganappi Trail of Calgary, Alberta and spans 1127 hectares making it the largest government owned park in Calgary.
Calgary is situated between two different ecological biomes; a region of the earth that we identify as having certain patterns with temperature, precipitation, and living organisms. The biomes that Calgary can be considered both in are the Grassland biome and the Boreal Forest. Nose Hill Park is a well preserved natural area that is controlled by the municipal government and is open to the general public.
As we first entered the park, we noticed the no dogs sign. We were told that because of the abundance of ducks and other organisms, dogs were banned in order for the ducks to remain in their environment undisturbed and safe. We learnt that Nose Hill pond is a drainage pond, used to collect and store rainwater from surrounding neighbourhoods such as Edgemont and Ranchlands. The pond also provides the only major water resource for surrounding organisms in Nose Hill, as the other sources come and go according to fluctuating rain levels.
  For this entry, we will be exploring aspects of the pond such as the significance of the organisms, how they interact, and the pond environment that these little creatures live in. The main focus of our entry is to discuss the effect of a realistic natural disaster on the species that we have captured and identified.
We observed specifically the storm drainage pond, pictured in figure 1.

Figure 1.  A picture of Nose Hill Pond taken on September 22, 2011 by Elizabeth in SWC’s Bio 20 IB class using a Canon PowerShot SD850 IS.

With one simple swoop of a butterfly net, we were able to capture several insects including the damselfly and a daddy long-leg spider, which is mentioned later in Table 1. The surrounding vegetation around the pond provided a perfect habitat for the damselfly to flourish, as we also observed a couple of damselfly attempting to reproduce. Unfortunately, my partner interrupted them during the copulation as he tried to catch them. We also caught a couple of aquatic organisms such as leeches. They are quite unique as they, like their name suggests, “leech” blood from other organisms to survive. This is an example of parasitism, a type of symbiotic relationship, or in simpler terms, interaction between organisms. Parasitism is an interaction between two organisms in which one organism benefits while the other is negatively affected, physically in the case of the leeches. This is just a small sample of the kind of interactions Nose Hill pond houses. Other samples of interactions between organisms include mutualism, commensalism and Intraspecific competition. For starters, intraspecific competition is competition between two organisms within the same species for a limited resource; a perfect example of intraspecific competition in Nose Hill pond is the competition between mating in damselflies. When we caught our damselflies, we noticed that two of them (presumably the males) were fighting for the lone female in the plastic bag, much like other species in the wild. We will be talking about the importance of symbiotic relationships later in this blog, as well as the consequences when these relationships are threatened by natural disasters.

            In our adventure, we identified the following species as shown in table 1.

Species (common name)
Scientific Name
Physical Descriptions
Daddy Long Legs Spider
Pholcus Phalangioides
Roughly 1cm body length (not including legs), legs 5 or 6 times the length of the body.
Brownish grey in colour with darker brown markings on the body.
Water Boatman
Corixa Punctata
Aquatic insects that paddle along the surface of water. Although aquatic, they lack gills. Normally grow between 5 – 15 mm long. Are able to stay buoyant due to the tiny hairs on their legs.
Ischnura heterosticta
Roughly 4 cm in body length. Bright blue in colour. Structurally similar to dragonflies but slimmer, generally smaller and their wings fold over backs.
Roughly 0.7cm in body length,

Table 1. Some of the species identified from the Nose Hill storm-drainage pond in Calgary, Alberta by Jeff Ma and Elizabeth Tang, students of the 2011 Biology 20 IB class at Sir Winston Churchill High School.

The significance of our topic is due to the idea of succession; the gradual and orderly process in which an ecosystem undergoes progressive replacement of organisms. We will evaluate how an organism will recover after a natural disaster where the habitat is heavily damaged and is in need of serious repair. In order to evaluate the effect of a natural disaster on the species, we have to become aware that interactions that occur between these four organisms as well as other interactions that occur in general areas such as the pond.
In  Calgary, the major realistic natural disasters that can occur based on historic trends are hailstorms, tornados, flash floods, and fires.
If any of the mentioned natural disasters happened to hit our Nose Hill drainage pond, the most evident effect these natural phenomenon would be physical destruction of flora leading to an unsettling of the trophic levels because of the lack of producers that feed the primary consumers. Trophic levels are the ranking of living things by their order of consumption. Producers include plant life that use solar energy to fabricate energy for themselves. Primary consumers are the organisms that consume producers, followed by secondary consumers and tertiary consumers as shown in the following diagram.

Figure 3. The Trophic Levels of organisms. Arrows signify consumption of one organism by another, through the different trophic levels.

Damage specific to a fire would be heavy destruction of all plant life compared to other disasters such as tornadoes, flash floods, and hailstorms. Damage specific to both a flash flood and hailstorms would be over fertilization and imbalance of nutrients due to erosion and presence of debris from property damage and drowning. Over fertilization includes high levels of phosphate, nitrogen and potassium which will lead to an algae bloom. This coverage of aquatic plants not only blocks sunlight for the underwater organisms, but it reduces the oxygen levels as well.
Many organisms depend heavily on these relationships, hence the term, symbiosis which means living together. Therefore, if something like a natural disaster were to happen, wiping out a good percentage of a certain species due to loss of habitat or food, other organisms that depended on that one species will suffer as well. To put it simply, all organisms made and will make connections that, if broken, cause ripples throughout this web of life. Natural disasters initially cause habitat destruction; this reinforces the idea and importance of succession, where the ecosystem gradually undergoes a change in which organisms will adapt physically or behaviourally.
Why is succession so important? It is simply because if every natural disaster that occurred wiped out the entire population of every organism it encompassed, soon enough, every species would become extinct.
All in all, the pond that we visited in Nose Hill is an essential habitat to many organisms and houses several symbiotic relationships. It also provides a significant resource of water for many surrounding organisms. We conclude this entry based on the realization of how truly vital this pond is, not only to the many organisms immediately surrounding the area, but of those all connected through the different trophic levels and the Calgary area as a whole. These interactions mentioned in the blog will not be possible without the location of the pond, the pond itself and the vegetation surrounding it.

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