The document discusses the effects of drainage systems and dumping from the Sedgewick landfill on the succession of Comosun Bog towards a forest ecosystem over the past 100 years. It notes that the drainage decreased soil moisture while the dumping and increased decomposition enriched the soil nutrient regime. To analyze the specific impact of the dumping, at least two sites must be examined - one near the dumping and a control site farther away. Species composition, soil nutrients, and moisture will be compared between the sites to determine if the dumping site exhibits greater changes indicative of richer soils. Understanding the extent of each disturbance will help predict regeneration and guide appropriate conservation efforts to maintain the bog environment or encourage natural succession.

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Hannah Crisp
40276123
11/11/14
Effects of Sedgewick Landfill Dumping on Comosun Bog
During the past 100 years, several disturbances have triggered Comosun Bog’s
succession towards a forest ecosystem. The installation of a drainage system has decreased the
bog’s vitally wet soil moisture regime. The bog’s soil nutrient regime has been enriched by a
combination of fire, increased decomposition rates, the old Sedgewhick landfill dumpings near
the bog and nitrogen-fixing species such as Alnus rubrus (red alder) migrating to the site to take
advantage of the increasingly aerobic soil. The City of Vancouver is tasked in determining the
extent to which the Sedgewhick landfill dumping has contributed negatively to the structure,
function and quality of the early successional forest currently over-taking the bog system. This
relationship will be examined by comparing alpha biodiversity, primary nutrient sources and soil
nutrient and moisture regimes between sites affected and unaffected by the dumped material.
Without the Sedgwhich landfill dumping, the bog site would nonetheless continue
succeeding towards a forest ecosystem due to drainage and the resulting species altering the
nutrient regime. It is critical in our analysis to separate the effects of the drainage systems and
that of the Sedgewhick landfill dumpings. For this reason, at least two sites must be examined:
one near the Sedgewhick landfill dumpings and another control site on the north western side of
the bog that is some considerable distance from the dumping site so that it is negligibly affected
by the added nutrients. Other factors that could alter the successional factors in each site must be
considered, such as their relative distance from the main drainage systems, their slope position
(water shedding vs. water receiving) and their percent ground cover by nitrogen-fixing species
such as A. rubrus. Sites should be chosen that exhibit minimal differences in terms of other
factors − besides proximity to dumping− that affect soil moisture and nutrient regimes.
On each site, alpha biodiversity will be measured by determining the percent ground
cover of each species present in the plot. In the original bog ecosystem (and in the remaining
bog), the dominant plants are indicative of poor, wet environments; for example, Ledum
groenlandicum (Labrador tea), Sphagnum spp. (sphagnum mosses) and Kalmia polifolia (bog
laurel). Dominance of plants that indicate a medium wet site, while maintaining the poor nutrient

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regime (e.g. Vaccinium parviflorum (red huckleberry), Gaultheria shallon (salal), Blechnum
spicant (deer fern)) will indicate a site that has been affected by increased soil aeration, but not
by a substantial change in nutrients. Due to the fire that released nutrients and the increase in
decomposition, some change in nutrient regime is expected to have occurred on both sites. If the
dumping site is more highly dominated by species indicating a medium-to-rich soil nutrient
regime (e.g. Rubus spectabilis) than the control site, this could indicate a correlation between the
increased nutrients brought in by the dumped material and site biodiversity.
A change in species composition is a change in ecosystem structure, which in turn affects
function. Species that relied on the poor soil nutrient regime will eventually be outcompeted as
their niche is lost. Any species that interact with these declining species populations will also
face a decline. A loss in current species populations would substantially reduce biodiversity and
consequently decrease ecosystem stability, negatively affecting the quality of the forest. The
large influx of nutrients would likely cause succession towards a more unstable ecosystem than
the succession affiliated solely with increased drainage. In the latter site, nitrogen fixing species
such as A. rubrus would likely still contribute nutrients, but the A. rubrus will contribute a more
sustainable source of nutrients than the temporary pile of nutrient-rich dumped material that
could be leached away. The succession via drainage would resemble a natural fen-to-woodland
pattern, whereas the succession via added nutrients resembles situations in which added
fertilizers cause destructive nutrient and species imbalances.
It is expected that both plots will exhibit a biota that reflects a richer soil nutrient regime
and drier soil moisture regime than the original bog. However, the species composition on the
site affected by the dumped material will likely have a higher dominance of species that prefer
nutrient rich soils, as well as a decline in the original bog species that prefer poor sites. This
drastic change in structure would adversely affect function and stability. Ideally, neither the
drainage nor the dumping would have occurred and the bog ecosystem would continue to support
the unique biota that thrives on poor, wet sites. By understanding the extent to which each
disturbance has affected the ecosystem, regeneration patterns can be predicted and appropriate
conservation methods can be applied, either to maintain the bog environment or encourage
natural succession.

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References
The Crazy Boggers. Invasives, Natives. Retrieved from
http://camosunblog.blogspot.ca/p/invasives-natives.html
Brown, Laurence (2011). The Bog’s History. Retrieved from Maylone Productions Inc for the
Camosun Bog Restoration Group website:
http://www.camosunbog.org/frames_about.htm