The Ecozones of Saskatchewan

Boreal forest in Saskatchewan, Canada (Branimir Gjetvaj Saskatchewan Photography)

The Province of Saskatchewan is located in southwestern Canada with a population of 1.1 million as of July 2013 that contains boreal forests and prairie used by humans for mining and timber (Bureau of Statistics, Government of Saskatchewan). A boreal forest, also known as a taiga, is a region of coniferous forest located just south of the tundra in high latitude areas. The boreal forest is characterized by extremely cold winters and little precipitation (50 cm per year), acidic and mineral poor soils, and a thick surface layer of partly decomposed pine and spruce needles (Berg et al., 2011). A prairie is an ecosystem that is part of the temperate grassland biome which is characterized by hot summers, cold winters, a mixture of grasses and herbaceous flowering plants, and average annual precipitation of about 25 to 75 cm (Berg et al., 2011). The biomes of Saskatchewan can be further broken into four main ecozones: the taiga shield, the boreal shield, the boreal plain, and the prairie (Padbury et al., 1998).

Map of Canada showing political province borders and ecozones. Saskatchewan contains four different ecozones: taiga shield shown in beige, boreal shield shown in gold, boreal plains, shown in light brown above, and prairies shown in dark brown (Torsten, McGill University).

The taiga shield ecozone, in northernmost Saskatchewan, is characterized by short summers and long winters with long nights. The mean annual temperature is 31 degrees, and the precipitation ranges from 200-1000 millimeters per year. The taiga shield in Saskatchewan contains wetlands, forests, meadows, and shrublands, and some of the most common trees are the black spruce, jack pine, and green alder, and shrubs such as cottongrass, lichen and moss thrive in the taiga shield (Torsten, McGill University). Megafauna including both herbivores and carnivores such as moose, woodland caribou, wolves, and lynx populate this ecozone.

The boreal shield ecozone is typified by large areas of exposed bedrock, forests, and large rivers. The mean annual temperature is 31 degrees, with rainfall averaging 400 cm. The vegetation is characterized by coniferous trees, including white spruce, black spruce, and balsam firs. Frequent forest fires make various stages of tree growth common. The animal population is similar to that of the taiga shield ecozone (Torsten, McGill University).

The ecozone of central Saskatchewan is the boreal plains, with an annual mean temperature of near freezing, and due to the Rockies blocking most atmospheric moisture, around 400 millimeters of precipitation. This region contains many lakes due to glacial melting. Despite heavy logging, the boreal plains of Saskatchewan are heavily wooded with fire-adapted trees including spruce, fir and pine species (Torsten, McGill University).

Lastly, the southernmost ecozone in Saskatchewan are the prairies. This ecozone is more temperate than the above, with mean winter temperature of 10 degrees celsius, and mean summer temperatures of 15 degrees celsius. However precipitation is very low due to the rainshadow effect. This in combination with high winds make the prairies of Saskatchewan extremely dry. Due to a large amount of agriculture, the original plants in the praries are dwindling, but include spear grass, wheat, blue grama grass, sagebrush, and chokecherry. The only large carnivore in the prairies is the black bear, however large herbivores include whitetailed deer, mule deer, pronghorn antelope, and elk. Rodents are particularly numerous (Torsten, McGill University).

Current Human Impacts

The main industries in Saskatchewan are timber, agriculture, oil, and mining. Deforestation due to the timber industry has been a problem in Saskatchewan for decades and accounts for 1.7 - 2.5% of Canada’s total CO2 emissions (Fitzsimmons 2003). Not only does deforestation result in increased carbon emissions, but the fragmentation caused by cutting down trees alters the spatial structure of landscapes affecting plant and animal life (Fitzsimmons 2002). In forests that have been fragmented due to deforestation, bird species variety was less  and had a lower daily nest survival than in areas of contiguous forest (Fitzsimmons 2002). The largest decreases in wooded areas in the boreal forests occurred in agricultural areas where the forests have no legal protection (Fitzsimmons 2003). About 95% of Saskatchewan’s prairies have been converted into farmland (Torsten, McGill University).

Source: Saskatchewan and Its People

http://www.rootsweb.ancestry.com/~cansk/SaskatchewanAndItsPeople/VolumeII/logginginnorthernsaskatchewan.html

Saskatchewan also uses hydroelectric power, which can have a large impact on aquatic ecosystems. There are different types of hydroelectric power plants; the more common type is the reservoir plant which requires the building of dams (SaskPower Hydro). Building large dams is damaging to aquatic ecosystems; biodiversity; the natural flood cycle on downstream floodplains; fisheries in the upstream, reservoir and downstream areas; and water quality (World Commission on Dams). In addition, building dams causes the build-up of sediment behind the dam which reduces the flow of nutrients downstream and impacts aquatic and waterfowl ecosystems (World Commission on Dams). The consequence of trapped sediment also acts as a physical barrier for river species who need to travel upriver to hatch their young (World Commission on Dams).

Video of the Gardiner Dam spillway, on the South Saskatchewan River, Saskatchewan, Canada. Gardiner Dam is the third largest embankment dam in Canada, and one of the largest in the world.

Mining is one of Saskatchewan’s most fruitful industries, the main products being potash, uranium, coal, and kaolin clay. Uranium mining in particular has been the subject of environmental impact studies. Uranium mining and milling operations have the potential for trace elements such as U, Ni, As, Se and Mo to be released into the ecosystem (Muscatello et. al, 2008).

Location of Key Lake Uranium Mine within Saskatchewan, Canada (Wikipedia).

Muscatello et. al. 2008 and Wiramanaden et. al. 2009 both performed studies measuring the bioaccumulation of selenium downstream from the Key Lake Uranium Mine in northern Saskatchewan, Canada. After tests of Selenium concentration in water, sediment, and biota, Muscatello et. al. 2008 found that the selenium concentration in the sediment and biota did not depend on the selenium concentration in water, and that biomagnification resulted in a 1.5 to 6 fold increase in selenium content between plankton, invertebrates, and forage fish. They also found that the Selenium content in exposed organisms exceeded the set dietary toxicity threshold for fish of 3-11 milligrams/g dry weight, indicating potential for reproductive harm to fish. Wiramanaden et. al. 2009 also found evidence supporting biomagnification of selenium downstream from Key Lake Mine. The measured concentration of selenium in sediment at all sites exceeded the proposed thresholds for the protection of fish and aquatic birds.

Table 1: Quantification of mining productivity by product by year in Saskatchewan, Canada.
(Saskatchewan Ministry of the Economy, updated November 2013)

Potential Improvements to Human Impacts and Future Prospects

In order to help reverse the effects of deforestation, reforestation of agricultural lands has been proposed to offset carbon emissions (Fitzsimmons 2002). Reforestation would require increasing the size of provincial forests or protected areas, or restoring forest cover adjacent to them which would reverse some of the degradation caused by fragmentation of forest ecosystems (Fitzsimmons 2002). One of the ways that the government of Saskatchewan is reducing the effects of deforestation is by creating new, protected ecological reserves where no new industrial developments will be allowed such as the new Pink Lake Representative Area Ecological Reserve, located 160 kilometres north of La Ronge (Nicholson 2013). As of July 2013 it is now Saskatchewan’s largest provincially-designated protected area; approximately 3,660 square kilometres (Nicholson 2013). The biofuel industry is also responsible for much of the deforestation in Saskatchewan. A proposed solution that has worked in some areas of Europe is planting fast-growing species such as the poplar and willow to burn instead of slower-growing species (Coxworth 2007). In addition, it has been proposed that converting forestry and agricultural crop residues to fuel would decrease waste and increase the total amount of biofuel produced (Coxworth 2007).

There are many ways in which to mitigate the effects on wildlife (in particular freshwater fish) of dams used to generate hydroelectric power, including changes to the structural features of the dams, operational change, predator control, and hatchery construction (FWEE, 2013). Structural improvements than can be made are centered around devices allowing fish to easily bypass the dam, including fish screens, fish-friendly turbines, surface collectors, fish ladders, spill deflectors. Operational changes to the dam affect either the rate of water flow through a dam, or how water passes through a dam. In order to minimize migration time, more water is released when juvenile fish are migrating, effectively flushing them through the dam. Alternatively, permanent drawdowns continually create a water level at the mouth of the dam that is lower than upstream, thus causing an increase in water velocity ahead of the dam. The effect of predators of fish such as predatory fish and aquatic birds can be mitigated below the dam by providing incentives to fisherman for catching predatory fish, and by installing a piano string mesh above the water, causing difficulty for birds to see fish in the river. Lastly, it is possible to reduce the diminishing effect on fish population by creating hatcheries that breed and release fish into rivers (FWEE, 2013). Since building large dams to power reservoir hydroelectric plants, future plants must be away from population centers in the northern parts of Saskatchewan and must be small-scale, run-of-the-river installations (Coxworth 2007).

One way to decrease the negative environmental impact of mines is to increase monitoring and regulations. In his 2004 report, Jarrell outlines initiatives that are being taken by the Key Lake uranium mine in Saskatchewan, Canada to treat their liquid effluent. Key Lake Mine performs a routine, semi-annual, 96-hour static acute lethality test on rainbow trout fry. If this test is failed, a Toxic Identification Evaluation (TIE) study is carried out, involving a systematic fractionation of the effluent mixture in order to characterize, isolate, and identify the toxic constituent(s) (Jarrell, 2004). Reverse osmosis membranes are used to filter trace elements such as iron ions and nickel. Currently, the Key Lake mining operation is transitioning from a water-based ecological assessment to a sediment-based ecological assessment, shown to be a more accurate measure of trace element concentration (Jarrell, 2004).

References

Coxworth, Ann, ed. "Towards a Sustainable Energy Strategy for Saskatchewan - See More At: Http://climateactionnetwork.ca/2007/01/14/towards-a-sustainable-energy-strategy-for-saskatchewan/#sthash.JxzWEwJB.dpuf." Saskatchewan Environmental Society (2007): n. pag. Print.

Berg, Linda R., Mary Catherine. Hager, and David M. Hassenzahl. Visualizing Environmental Science. Hoboken, NJ: Wiley, 2011. Print.

Bernhardt, Torsten, Canadian Biodiversity Website: McGill University, Canadian Heritage, Montreal, Quebec, Canada, “http://canadianbiodiversity.mcgill.ca/english/index.htm.”

Fitzsimmons, M.J., 2002, Estimated rates of deforestation in two boreal landscapes in central    Saskatchewan, Canada: Canadian Journal of Forest Research, v. 32 p. 843-851.

Fitzsimmons, M.J., 2003, Effects of deforestation and reforestation on landscape spatial   structures in boreal Saskatchewan, Canada: Forest Ecology and Management, v. 174, p.        577-592.

Fitzsimmons, M.J., D.J. Pennock, and J. Thorpe, 2004, Effects of deforestation on ecosystem    carbon densities in central Saskatchewan, Canada: Forest Ecology and Management, v.        188, p. 349-361.

Foundation for Water and Energy Education (FWEE), 2013, Protection, Mitigation, and Enhancement Strategies at Hydroelectric Projects: FWEE, Seattle, Washington USA, Web 24 Nov. 2013.

Government of Saskatchewan. "Quick Facts." Bureau of Statistics. N.p., n.d. Web. 22 Nov. 2013.

"Hydro as a Generation Option." SaskPower Hydro as a Generation Option Comments. N.p., n.d. Web. 23 Nov. 2013.

Jarrell, J.P., 2004, Treatment of liquid effluent from uranium mines and mills, report of a co-ordinated research project, “Liquid effluent treatment initiatives at Key Lake uranium mine, Saskatchewan, Canada, 1996-2000”: International Atomic Energy Agency, Vienna, Austria p. 45-73.

McLaughlan, M.S.; Wright, R.A.; Jiricka, R.D. 2010. Field guide to the ecosites of

Saskatchewan’s provincial forests. Saskatchewan Ministry of Environment,

Forest Service. Prince Albert, Saskatchewan. 343 pp.

Muscatello, J.R., A.M. Belknap, and D.M. Janz, 2008, Accumulation of selenium in aquatic       systems downstream of a uranium mining operation in northern Saskatchewan, Canada:   Environmental Pollution, v. 156, p. 387-393.

Nicholson, Val. "NEW ECOLOGICAL RESERVE IS SASKATCHEWAN'S LARGEST."Government of Saskatchewan, June-July 2013. Web. 27 Oct. 2013. http://www.gov.sk.ca/news?newsId=ce66ce19-df12-4732-bceb-f6b9c7252b86

Padbury, G. A., D. F. Acton, and C. T. Stushnoff. Ecoregions of Saskatchewan. Regina: Canadian Plains Research Center, 1998. Print.

Wiramanaden, C.I.E., E.K. Forster, and K. Liber, 2010, Selenium distribution in a lake system receiving effluent from a metal mining and milling operation in northern Saskatchewan,       Canada: Environmental Toxicology and Chemistry, v. 29, no. 3, p. 606-616.

World Commission on Dams. Dams and Development: A New Framework for Decision-making : The Report of the World Commission on Dams. London: Earthscan, 2000. Print.