Section 3: Ecosystems and their goods and services at the national level
Canada’s main ecosystem types include forests, wetlands, grasslands, tundra, lakes, rivers, and coastal and marine areas. At this large scale, changes in the quality of terrestrial and aquatic ecosystems can be seen by measuring changes in variables such as land cover or ecosystem productivity over time.
This section presents an overview of measures of the quality and productivity of ecosystems using a suite of national level experimental indicators developed as part of the MEGS project. These indicators were designed and developed to measure land cover change, landscape modification, ecosystem service potential and biomass extraction. In addition, measures of fish harvest—an important provisioning service from marine areas—and measures of ecosystem goods and services (EGS) provided by wetlands are also presented.
Land cover change, Canada
Tracking changes in land cover and land use is a useful starting point for studying the state of terrestrial ecosystems. Land cover change resulting from developmental pressures such as the expansion of roads and settlements can affect the quality of ecosystems and their capacity to deliver EGS. However, land cover alone cannot fully explain land’s ability to support and maintain ecological processes and functions. For example, the corridors connecting natural land parcels are important determinants of land’s ability to support habitat and wildlife.
Broadscale analysis of land cover based on the MEGS geodatabase shows that forest and shrubland are the dominant land covers in taiga and boreal ecozones, 1 a majority of the Prairies is in cropland and Canada’s arctic is mostly barren (Map 3.1).
From 2001 to 2011, evergreen, deciduous and mixedwood forest areas across the country decreased from 3.1 million km2 to 3.0 million km2 (-4%), while shrubland increased from 2.4 million km2 to 2.5 million km2 (+4%). Built-up areas in and around cities and towns across Canada increased 8% from 8,996 km2 to 9,680 km2 over the same period (Table 3.1). Put in perspective, these areas grew by an area roughly the size of the City of Toronto.
Many of these changes are the result of the transformation of cropland and forests in the areas surrounding cities and towns (Table 3.2). For example, from 2000 to 2011, 3,361 km2 were converted to built-up area in the southern part of the country. 2
The loss of some of Canada’s best agricultural land through conversion to other uses is a concern given the limited amount of this non-renewable resource. Only about 5% of land in Canada is free from severe constraints to crop production. 3 From 2000 to 2011, there was a 19% increase in the settled area occupying this dependable agricultural land in Canada and a 29% increase on the very best Class 1 agricultural land. 4 , 5
Some cropland also reverted to a more natural land cover, with 9,118 km2 shifting to shrubland from 2000 to 2011 (Table 3.2).
Focus area: Greater Golden Horseshoe
Land cover analyses can also focus on changes at regional or local scales. 6 In southern Ontario, the Greater Golden Horseshoe area covers almost 33,200 km2. Located to the west of Lake Ontario, it includes some of Canada’s largest cities (Map 3.2). The area, named for its economic wealth and horseshoe shape, has a high concentration of economic activity, as well as some of Canada’s best agricultural land. In 2011, the Greater Golden Horseshoe was home to 26% of the Canadian population.
Increasing urbanization in the Greater Golden Horseshoe has placed pressure on the landscape. Within the Greater Golden Horseshoe, population has grown from 4.5 million in 1971 to 8.7 million in 2011 (Table 3.3). In 1971, two-thirds of the population living in the Greater Golden Horseshoe was located in the central settled areas around Toronto, Oshawa and Hamilton, inside the greenbelt. With increasing population growth, the number of people living in these areas increased by 36%. However, population growth increased much more in the adjacent area, increasing from 39,148 in 1971 to 1.8 million in 2011. Overall, the proportion of the population living inside the greenbelt, in the greenbelt and outside the greenbelt remained largely unchanged over the same period.
Recognizing the developmental pressures associated with population growth, in 2005 the government of Ontario established a ‘greenbelt’ covering 22% of the Greater Golden Horseshoe area, protecting farmland, wetlands, forests and other green space from urban development. 7 When the greenbelt was established, the area between it and the existing settled areas was identified to accommodate further urban expansion and is known as the whitebelt. Consisting of rural and agricultural land, this area is under pressure from population growth and competing land uses.
From 2000 to 2011, settled area in the Greater Golden Horseshoe increased by 28%, from 2,972 km2 to 3,807 km2 (Table 3.4). For the area outside the greenbelt, the largest proportion of this change occurred as natural land 8 was converted to settled area. Inside the greenbelt, almost 300 km2 was converted to settled area, more than two-thirds of which was converted from agricultural land area. Given the limited availability of good quality agricultural land in Canada, losses of this non-renewable resource could have implications for longer-term agricultural sustainability.
Ecosystem quality measure: Human landscape modification
Landscapes that are least disturbed by human activity are generally better able than modified landscapes to maintain the complex ecological functions that support the production of EGS. Land cover, landscape measures and human pressures were analyzed by sub-drainage area (SDA) 9 in order to better understand the status of terrestrial landscapes.
This assessment focuses on five measures of ecosystem quality: landscape type, natural land parcel size, 10 distance to natural land parcel, 11 barrier density 12 and population density (Tables 1, 2 and 3, Appendix C). These measures provide information on the overall integrity of natural areas and present changes in land cover and population as indicators of the quality of terrestrial ecosystems. Together, these five human landscape modification measures provide information about how human activity has modified natural land areas across Canada.
Landscape type
The type of landscape, as well as changes in land cover over time, can provide information on the degree of human modification to the landscape and changes in the provision or flow of EGS. Terrestrial landscapes 13 are grouped here into three categories: natural or naturalizing areas, 14 agricultural land areas and settled areas. 15
Natural landscapes represent some of the least modified areas including forests, wetlands, barrenlands, grasslands and shrublands. Agricultural land can be moderately to highly modified from the natural landscape, while settled areas are highly modified from their natural state. The conversion of land to a more highly modified state can affect ecosystem productivity. For example, the conversion of land from a natural area to a settled area can have impacts on available habitat and biodiversity. However, the term ‘natural’ does not imply these areas are all highly productive—some natural landscapes may not be significant providers of EGS.
Natural landscapes are the dominant land cover type in most areas of the country, but certain areas of the Prairies, southern Ontario, the St. Lawrence River Valley in Quebec, as well as Prince Edward Island, have a much higher proportion of modified landscapes when compared to other SDAs (Table 2, Appendix C).
SDAs with the lowest percentage of natural landscapes in 2011 were found in the Prairies in the Lower South Saskatchewan-05H (8.5%) and Battle-05F (8.9%). These SDAs also had the highest percentage of agricultural landscape.
SDAs with the highest percentage of settled land were located in the heavily populated areas of the Windsor to Québec City corridor in southern Ontario and Quebec. They include the Lake Ontario and Niagara Peninsula-02H, with settlements covering 11.4% of the landscape; the Central St. Lawrence-02O (7.7%) and the Northern Lake Erie-02G (6.6%).
Conversion to and from natural or naturalizing and agricultural landscapes
From 2001 to 2011, the largest changes in land cover occurred as agricultural land reverted to natural or naturalizing landscapes. 16 The largest shifts occurred in the southern Prairies, particularly in the Qu’Appelle-05J, Assiniboine-05M, Lower South Saskatchwan-05H and Lower North Saskatchwan-05G SDAs which together saw an area of 10,475 km2 reverting to a natural or naturalizing landscape from agricultural land. To put this figure in context, this change represents an area three times greater than the land area of the Regina census metropolitan area (CMA). Other large shifts occurred in the Upper Peace-07F SDA, where 1,258 km2 reverted to a natural or naturalizing state.
The largest conversions to agricultural land were from natural landscapes and these occurred in the Upper South Saskatchewan-05A (1,468 km2) and the Thompson-08L (973 km2) SDAs.
Conversion to settled landscapes
Between 2000 and 2011, 3,158 km2 was converted from agricultural and natural land to settled areas. The largest increases in settled landscapes from 2000 to 2011 occurred in Ontario and Quebec. The largest single increase of any SDA was in the Lake Ontario and Niagara Peninsula-02H SDA, which includes Toronto—an increase of approximately 627 km2 in settled area—mostly at the expense of agriculture (Map 3.3).
Other large increases in settled area occurred in the Central St. Lawrence-02O (311 km2), Northern Lake Erie-02G (310 km2), Bow-05B (201 km2) and Central North Saskatchewan-05E (198 km2). Most of these increases were also at the expense of agricultural land.
There were no substantial decreases in settled landscapes anywhere in Canada.
Natural land parcel sizes
The size of natural land parcels can provide insight about landscape fragmentation and also its ability to maintain ecosystem functions. For example, larger natural areas generally provide better habitat for wildlife. 17 Smaller areas may provide fewer resources and may result in increased competition between species, which can lead to effects like decreased species richness.
The smallest average natural land parcel sizes in the country are found in SDAs with the largest human populations and the most agricultural activity, including the Prairies and southern Ontario. The two southern Ontario SDAs of Eastern Lake Huron-02F and Northern Lake Erie-02G had average natural land parcel sizes of 0.8 km2 and 0.3 km2 in 2011. The average parcel size for eight (O5E to 05J and O5M to 05O) of the most modified SDAs in the Prairies was between 0.3 km2 and 0.8 km2, among the smallest in Canada.
Natural land parcel sizes are generally larger in the Maritimes than in the highly modified landscapes of the Prairies, southern Ontario and the St. Lawrence Valley in Quebec. Prince Edward Island-01C had the smallest average natural land parcel size in the Maritimes (2.3 km2).
In comparison, the average natural land parcel size in the Lower Fraser-08M SDA in B.C. was 80.6 km2.
Distance to natural land parcels
The average distance to a parcel of natural land provides another indication of the level of landscape modification. For example, the distance to natural land parcels can affect the ability of pollinators to disperse pollen from one natural area to another. As the distance increases, it becomes more difficult for species to move from one area to another, potentially decreasing genetic diversity.
The farthest average distance to natural land parcels is found in the Prairies in the Qu’Appelle-05J SDA, with an average distance of 1,295 m in 2011. The Souris-05N and Lower South Saskatchewan-05H SDAs also have an average distance to natural land parcels of greater than one kilometre (Table 3, Appendix C).
In the other highly modified landscapes of southern Ontario and the St. Lawrence Valley in Quebec, there are three SDAs (O2F, O2G and O2M) with average distances to natural landscapes of over 250 m. Prince Edward Island-01C has the farthest average distance in the Maritimes with an average distance of about 230 m. In contrast, many SDAs had short average distances to natural land parcels, for example, the Abitibi-04M SDA in Quebec had an average distance of 9 m.
Barrier and population densities
Roads and infrastructure such as rail and transmission lines represent another type of landscape fragmentation. These linear features cut across the landscape, splitting it into smaller patches. These barriers generally degrade habitat, though they increase the perimeter of natural areas, which can be beneficial for some species. Roads also increase access to natural landscapes, allowing better provision of recreational and educational services. 18
Barrier density, population, and settled areas are interconnected issues. Higher barrier densities generally coincide with higher population densities, as seen in all four SDAs in southern Ontario (02E to 02H), the Upper and Central St. Lawrence SDAs in Quebec (02M and 02O), Red-05O SDA in the Prairies and Prince Edward Island-01C (Tables 1 and 3, Appendix C).
SDAs with the highest population densities from 2001 to 2011 are in southern Ontario and along the St. Lawrence Valley in Quebec. The highest densities are in Lake Ontario and Niagara Peninsula-02H SDA (272 people/km2) and Central St. Lawrence-02O (148 people/km2). Barrier densities are also high in these two SDAs, which include the cities of Toronto and Montréal, with an average of 2.2 km and 1.8 km of barriers/km2 respectively.
In the Maritime Provinces, Prince Edward Island-01C has the highest population density at 25 people/km2 and the highest barrier density of 1.4 km/km2. In the Prairies, the Bow-05B has the highest population density at 52 people/km2, while on the West coast, the Lower Fraser-08M, has a density of 33 people/km2.
Some of the largest increases in population densities are in the Prairies and southern Ontario—population density increased in the Upper North Saskatchewan-05D (27%), Bow-05B (28%), Red Deer-05C (19%), Central North Saskatchewan-05E (19%) and Lake Ontario and Niagara Peninsula-02H (16%).
These five indicators—landscape type, natural land parcel size, distance to natural land parcel, barrier density and population density—can be related and when viewed together they can help create a useful representation of the overall quality of an ecosystem.
Ecosystem services potential: Boreal forest case study
Ecosystem service potential is the capacity of landscapes to deliver goods and services without affecting ecosystem integrity. 19 , 20 This capacity is controlled by the ecosystem’s biophysical structures and processes such as climate, soils, land cover and productivity, which interact to generate ecosystem functions. 21 While ecosystem services require a human beneficiary to be considered as such, the potential to provide that service exists independently of use.
A framework for quantifying the potential of landscapes to provide EGS was developed in the context of the MEGS project. The boreal 22 forest case study was used to test and demonstrate the value of this approach (Appendix D). Ecosystem services that were addressed in the case study were habitat provision, carbon sequestration, resilience to epidemic insect outbreaks, opportunities for solitary wilderness experiences, prey for hunting, timber supply, scenic beauty, habitat for charismatic or iconic species, air filtration, soil fertility, and water purification.
The case study also applied an aggregate measure for assessing the total ecosystem potential—the overall relative ecosystem capability to deliver a number of different ecosystem services—while also representing the individual contribution of each EGS.
Information on a single regulating service—water purification—is presented here for illustrative purposes.
A regulating service: Water purification
Forest ecosystems can affect water quality in many ways. Riparian forests provide shade, which moderates water temperatures, and provide a source of organic debris and nutrients, which are used by aquatic organisms. Natural processes in forested areas, such as landslides, channel erosion, blowdown, and wildfire, can affect water quality by increasing sediment and nutrient concentrations and stream temperatures. Forests also modify the chemistry of incoming precipitation as a result of vegetation and soil interactions. Natural disturbances and management activities may change dissolved and chemical particulate concentrations in water bodies. 23
Water purification is defined as the filtration and decomposition of wastes and pollutants in water, as well as the assimilation and detoxification of compounds through soil and subsoil processes. Preliminary results of the study showed that the potential of boreal watersheds to purify water is largely intact, with 71% of the watersheds assessed experiencing no negative change in their water purification potential from 2000 to 2010 (Maps 3.4, 3.5 and 3.6). 24
While still relatively high, the water purification potential index of watersheds declined from 2000 to 2010 in some regions of the boreal forest, including in the south-west and eastern parts. Underlying causes of these changes varied and included, in no particular order, an increase in the area affected by forest fires, a decrease in forest cover and riparian forest buffer, and an increase in the area affected by settlements and other human landscape features (e.g., roads, powerlines).
Ecosystem productivity measure: National biomass extraction
Ecosystems have the capacity to provide or contribute to the production of many goods that people use including organic materials such as agricultural products, fish, and timber, which can collectively be referred to as ‘biomass.’ The extraction of these goods can place pressure on ecosystems, potentially reducing their ability to produce EGS in the future. For example, overfishing can deplete fish populations upon which people rely as a stock of natural resources; farming and forestry practices can result in soil erosion; and livestock production can degrade the productivity of pasture land and rangeland through overgrazing. Measuring the extraction of biomass is a step towards the development of indicators that help explain whether human use of ecosystem goods is sustainable. 25 , 26 For more information see Appendix E.
Table 3.5 shows the extraction of biomass for human use for the following categories: agricultural crops, livestock and poultry, milk, maple products and honey, forestry, and fisheries. An estimated 285.8 million tonnes of biomass were extracted for human use from Canada’s terrestrial and aquatic ecosystems in 2010. Biomass extraction related to crops was highest in Alberta, Saskatchewan and Ontario. The top three provinces producing livestock and poultry were Quebec, Alberta and Ontario. Quebec and Ontario account for the largest proportion of biomass extraction in the form of milk, maple products and honey.
Half of Canada’s forest biomass extraction came from British Columbia, followed by Alberta (15%) and Quebec (13%). Coastal fisheries accounted for the majority of Canada’s total biomass extraction from commercial fisheries, with the vast majority coming from the Atlantic provinces.
The largest proportion of biomass extraction occurred in British Columbia, as a result of the importance of forestry (Map 3.7). While proportionally less biomass was extracted in marine and coastal areas, this result can be attributed to the lower relative contribution of fisheries to total biomass extraction compared to agriculture and forestry. Comparatively little biomass extraction took place in Canada’s North.
Marine and coastal ecosystem goods and services
Oceans and coasts may provide as much as two-thirds of the planet’s ecosystem services. 27 However, marine and coastal ecosystems worldwide face many threats, including overfishing, coastal development and impacts related to climate change and ocean acidification. 28 Given the many gaps in knowledge about marine ecosystems, there is a high level of concern about the cumulative effects of these issues and their impacts on ecosystem components and functions, and on the provision of EGS.
Textbox 2: Marine and coastal areas
Canada’s marine and coastal waters cover about 5.6 million km2, 29 equivalent to about 56% of Canada’s land mass. They have been classified into 12 ecoregions based on oceanographic and depth similarities and general ecological features (see Appendix H). At finer scales there is a wide variety of ecosystem types, ranging from estuaries, bays, fjords and other coastal areas, continental shelves and slopes, and the open ocean.
There is a great deal of diversity in what can be found in any given area of the ocean, from below the seafloor to above the surface. Marine areas have characteristic patterns of temperature and chemistry, as well as predictable currents and tides. These characteristics will influence the types of organisms that live in each area including seagrasses and other marine plants; corals, sponges and other invertebrates like sea urchins and starfish on or near the bottom; phytoplankton and zooplankton, fish, and marine mammals such as seals, dolphins and whales; and seabirds in the land, water and air. These different parts and aspects of the ecosystem interact and influence each other, through predation, provision of shelter and competition for space and food.
Marine EGS depend on healthy marine ecosystem components, processes and functions. For example, fisheries rely on the structures and processes required to support productive fish populations, including reproduction, growth, survivorship, and availability of both the harvested fish and their prey. The oceans' carbon cycle relies on the dissolution and release of atmospheric carbon dioxide in the water, as well as on the absorption and release of carbon by marine plants—how these factors balance one another determines whether the oceans are a source or sink of atmospheric carbon dioxide. Recreational values may depend on the presence of fish species that people enjoy catching or on the diversity of life that can be seen when diving in coastal waters.
An important characteristic of marine ecosystems and their goods and services is the degree to which they are interconnected. Fishing that depletes one type of fish is likely to have indirect effects on other species as a result of numerous ecological relationships. Some fishing methods negatively impact marine habitats, undermining their productive potential and also potentially affecting other EGS. Higher levels of carbon dioxide in the ocean make it more acidic, which can impact shellfish 30 and can also create anoxic conditions, potentially leading to fish kills. 31
Fish—perhaps the best known provisioning service—can be captured for direct human consumption and to a lesser extent for animal feed. Fish are also increasingly farmed for human consumption.
Marine and coastal ecosystems also play an important role in regulating global climate both because of the ocean’s role in storing and moving heat, and because much of the carbon dioxide emitted into the atmosphere from burning fossil fuels and other sources eventually enters the ocean. 32 Oceans also dilute and store sewage and other waste products, while seagrasses and shoreline vegetation protect coastlines from erosion. 33
Cultural services with substantial economic benefits including camping, boating, fishing, diving and whale watching are also obtained from marine and coastal ecosystems. Other cultural services include the heritage value attached to the oceans and people’s interactions with them.
While many important EGS are obtained from the oceans, few data are available, with the exception of commercial fishery catches. 34 In 2011, commercial fish landings on Canada’s Atlantic and Pacific coasts totalled over 850,000 tonnes (Table 3.6). Two-thirds of the landed weight originated from relatively few areas (Maps 3.8 and 3.9).
Characterization of spatial relationships is important in understanding marine and coastal EGS. Areas with low landed weight can still be important to the well-being of a species being fished. Salmon, for example, hatch in rivers, sometimes hundreds of kilometres from the ocean, but spend much of their adult life feeding and growing in the ocean before returning to the same river to spawn. Species such as mussels spend most of their life in the same place, but their eggs and larval forms may drift for hundreds of kilometres before settling on the ocean bottom, while the food they filter from the water can also come from quite far away. These examples show how impacts on the ecosystem, such as pollution, can originate in one area but have significant effects on fish populations elsewhere.
Understanding spatial relationships is important for other marine and coastal EGS as well. Recreational services may be enjoyed more in highly populated areas where they are accessible to more people. However, pollution from distant sources can be transported into these recreational areas by ocean currents, affecting the enjoyment of the services by local residents and visitors. Other services, such as carbon sequestration, are provided by ecosystems distributed over a wider area, and the benefits are also more widely distributed.
Data that would allow assessment of the status of marine and coastal ecosystems and EGS are sparse. However, for commercial fisheries, relevant data exist because scientists and managers monitor and assess the status of fish stocks against benchmarks (e.g., healthy, cautious or critical status). In 2011, a summary of the status of 155 major Canadian fish stocks classified 46% as healthy, 20% as cautious, and 11% as critical, while the status of the remaining 23% of fish stocks was unknown. 35
Valuation of marine and coastal ecosystem goods and services
Each marine and coastal area may provide a wide range and quantity of EGS. Many are intermediate goods in a chain of production leading to a final good or service, and much work remains to untangle this web and produce sound monetary value estimates. A number of methods could be applied to assess values of these EGS (Appendix B).
Commercial fisheries catch is almost always associated with markets and financial transactions, and can therefore be tracked. On the other hand, other services provided by marine and coastal areas are usually not associated with markets. Explicit prices are therefore not observed through payment by beneficiaries; in fact, beneficiaries may not even be aware that they are benefiting.
In 2011, commercial fishery landings were valued at $2.1 billion (Table 3.6). Maps 3.10 and 3.11 show the areas in Canada’s Pacific and Atlantic waters where the greatest value is generated from these fisheries. The value of the fishery is unevenly distributed geographically, with the specific areas of concentration differing for each species group. Because of differences in market value for fish, lobster, crab and other species, the areas of highest value are not always the same as those accounting for the largest portion of landed weight. In addition, in some coastal areas, even a comparatively small landed value may be critical to the local economy.
Recreational fisheries offer another example of a service for which monetary value estimates are available—anglers’ direct expenditures for fishing trips in 2010 totalled $2.5 billion. 36 While much of this total was for freshwater fishing, expenditures on marine fishing trips in British Columbia alone totalled $368 million with a further $338 million spent on major purchases and investments wholly attributable to marine recreational fishing in the province. 37 A portion of these values is attributable to the fish themselves, but the value is also partly attributable to other aspects of the recreational fishing experience, some of which also rely in part on EGS.
Marine and coastal EGS provide benefits at many scales—these services range from recreational fishing in local waters to the critical carbon sequestration services provided by oceans at a global scale. Some beneficiaries have a more direct interest in the sound management of coastal and marine ecosystem assets since these assets directly support livelihoods through harvesting and processing activities. Maps 3.12 and 3.13 present the Canadian marine coastal fisheries ecumene. They focus on coastal areas at the ecodistrict level, 38 in which selected employment activities related to the marine environment—commercial fishing, aquaculture and seafood processing—are found. On the East coast, in 2006, these activities represented 14% of employment in those communities where the activities were present, compared with 4% on the West Coast (Table 3.7). In some of the smaller communities, these activities represented a third to nearly half of the employment. 39
Freshwater wetland ecosystem goods and services
As water moves through the environment it is transformed and transferred from one state to another and from one ecosystem to the next. Wetlands, areas where water accumulates for prolonged periods of time, play an important role in this cycling of water.
Wetlands are defined as lands that are seasonally or permanently covered by shallow water, including lands where the water table is at or close to the surface. Wetlands can be classed into two main categories—organic and mineral—and are further subdivided into five classes: marshes, swamps, bogs, fens, and shallow open waters.
As the interface between the aquatic and terrestrial environments, wetlands provide critical functions and EGS at global, regional and local scales. Some important functions and services provided by wetlands include the regulation of water flow and quality, soil retention and formation, and climate. Wetlands also provide habitat for many living organisms—plant and animal, terrestrial and aquatic—and provide opportunities for recreation and education.
Freshwater wetland extent in Canada
Wetlands exist in a diverse range of environments and natural settings across Canada (Map 3.14). Although there are many types of wetlands, two are of particular interest nationally and regionally because of their extent and number—peatlands and prairie pothole wetlands.
Peatlands are organic wetlands and are the most common type of wetland in Canada, covering approximately 12% of the landscape 40 and accounting for about 76% of total wetland area. 41 Large areas of peatland are concentrated in the Hudson Bay Lowlands, northern Alberta, central Northwest Territories and parts of Manitoba (Map 3.15). More than a third (37%) of the total extent of peatland is frozen year-round and is particularly sensitive to climate change. 42
The prairie pothole region—an area covering approximately 390,000 km2 or 22% of the Prairie provinces 43 —is known for the hundreds of thousands of small ‘pothole’ wetlands that dot the landscape. These small depression wetlands are usually less than 1 hectare (ha) in size, can have water present on a continuous or sporadic basis and can be connected to or isolated from surface waters in streams and rivers. 44 Although individually small, collectively these wetlands represent a major component of the hydrology of the Prairies.
Over the years, development and other pressures have resulted in all types of wetlands being converted to other land uses in and around agricultural and settled areas, resulting in important losses in wetland EGS. It is estimated that since 1800, 200,000 km2 of Canadian wetlands have been lost, due to drainage and other types of human activity. 45
In the Prairies, small pothole wetlands have experienced continuous land use pressure, with losses occurring at a higher rate than other types of wetlands, usually to agricultural land use. 46 Since 1900 between 40% and 70% of the potholes in the western Prairies of North America have been drained, mainly to increase agricultural production. 47 , 48 , 49
In southern Ontario, the area covered by large wetlands—those greater than 10 ha in size—decreased by approximately 72% from pre-settlement times to 2002. 50 Although the majority of this change occurred long ago, there was a 3.5% reduction from 1982 to 2002. 51
In Alberta it is estimated that up to 64% of wetlands have been lost from early settlement to 1996. 52 The government of Alberta has found that wetland area has decreased by 24% in the Shepard Slough, just east of Calgary, a loss of 7.7 km2 between 1962 and 2005. 53
The impact of climate change on wetlands is coming into increased focus due to changes in the water cycle including changes in the frequency, magnitude, timing and distribution of precipitation and increased temperatures particularly in arctic and subarctic regions. Researchers have found that approximately 60% of Canada’s peatland will likely be impacted by climate change, resulting in significant changes to their ecosystem services. Changes are already occurring and are expected to accelerate, resulting in degradation of permafrost in the subarctic and boreal regions and severe drying of peatlands in the southern portions of the boreal region. 54
Towards valuation of wetland goods and services
Recent studies in Ontario found that wetland ecosystems provide the highest value of services and are the most valuable ecosystems on a per hectare basis. 55 The value of EGS from Great Lakes coastal wetlands in southern Ontario is estimated at close to $15,000/ha/year. 56 In the Credit Valley watershed of southern Ontario, wetland services were estimated to have an annual benefit of $187 million/year. 57 Potential wetland values for recreation in the Shepard Slough region of Calgary were estimated at approximately $4.4 million/year. 58 The annual value of phosphorus and nitrogen processing by wetlands in British Columbia’s Lower Fraser Valley was estimated to be between $452/ha and $1,270/ha. 59
Although some organizations have determined monetary values for wetland EGS, from an accounting perspective, valuation remains a challenge due to difficulties in determining appropriate methods and a lack of data. To begin, the inventory of Canada’s wetlands remains incomplete, largely as a result of the size of the country and the number of wetlands, but also because of the complexity in delineating these areas.
As a result, this analysis focuses on contextual characteristics of the regional supply and demand for wetland goods and services as a way to understand the relative importance and value of specific wetland EGS in different areas of the country. 60 Contextual analysis allows for important aspects of value to be explored and better understood, particularly where monetary or physical measures are not feasible.
Tables 1, 2, and 3 (Appendix F) present supply characteristics and indicators of demand for wetland services by sub-drainage area (SDA) focusing on population density, agricultural land use, livestock density, land modification, 61 fertilizer application, and nitrogen and phosphorous from manure and comparing these indicators of demand to the extent or supply of wetlands in each area. For example, the Lake Ontario and Niagara Peninsula-02H, Central St. Lawrence-02O and Northern Lake Erie-02G SDAs have among the highest population and livestock densities and proportions of land in agriculture. These indicators help represent the pressure that humans put on ecosystems and can also indicate a higher demand for the services provided by wetlands.
The section also focuses in more detail on wetland EGS for a single drainage region—the Assiniboine-Red in the Prairies—as an example of how local and regional studies can determine the benefits of wetland EGS.
Streamflow regulating services
Wetlands modify the flow of water as it passes through watersheds, 62 lessening the magnitude of peak flows 63 and supplementing low flows. This flow regulation service is valuable in watersheds with a high variability of streamflow, peak flows that can result in damaging floods or low flows that exacerbate drought. In Canada, variability of flow, 64 flood hazards and drought conditions are most acute on the Prairies, although similar concerns exist on a more localized scale elsewhere. The floods in Calgary and High River in 2013 bring attention to the issue of streamflow variability, highlighting the importance of the benefits provided by wetlands.
The hydrology of Canada’s prairie region is highly variable, with fairly well-drained, semi-arid basins in the southwest part and many wetlands and lakes in the relatively wet north-central and eastern parts. 65 The Missouri-11A, Souris-05N and Western Lake Winnepeg-05S SDAs in the southern Prairies, had the highest water flow variability in the country (Table 3, Appendix F). This variability in water flow is one of a number of factors, which, if taken together, would favour higher values for particular wetlands.
Total water storage capacity lost due to wetland drainage in Calgary’s Shepard Slough region is estimated at 9.2 million m3 between 1965 and 2011. 66 This represents a 20% decrease in available water storage capacity—which would have an impact on the provision of flood protection services.
Water quality regulating services
Wetlands have the ability to trap and retain nutrients and pollutants that are dissolved or suspended in water, helping to purify or clean water. Information on phosphorous and nitrogen in livestock manure, fertilizer application, population and agricultural production provide context to explain the demand for and value of water quality regulating services offered by wetlands (Table 3, Appendix F).
Eutrophication—the nutrient enrichment of water bodies—is an important issue across Canada and is particularly important in areas that have been highly modified by human activities, for example in the Prairies, southern Ontario and southeastern Quebec. The Northern Lake Erie-02G SDA in southern Ontario had among the highest levels of land modification, represented by natural land parcel size, as well as some of the highest proportions of fertilized land area and amounts of nitrogen and phosphorous coming from manure (Table 3, Appendix F).
Soil retention and formation services
Soil retention and formation in wetlands occurs where eroded soil and suspended soil particles settle out of the water as they enter wetlands, rather than being transported away by streams or rivers. This soil retention process is particularly important in highly modified areas of the Prairies, the south shore of the St. Lawrence in Quebec, and southern Ontario, because erosion is more likely to occur where there is modification of the landscape.
Higher total suspended solids and turbidity 67 levels can be an indication that there is more erosion taking place. In 2011, turbidity levels of untreated surface waters supplying drinking water plants were highest in the Prairies and the St. Lawrence drainage regions. 68
Habitat provision services
Wetlands provide diverse habitat for terrestrial and aquatic organisms, for example nesting habitat for birds. Approximately 600 species of wildlife, including more than one-third of Canada’s species at risk, are found in wetlands. 69 Given their high biological productivity, wetland habitat services have a high value in all places but are particularly valuable in areas where wetlands are relatively scarce or where the landscape is highly modified, such as southern Ontario and the Prairies (Tables 1 and 3, Appendix F). Ranking SDAs by natural land parcel size indicates that the Prairies have eight of the top ten most modified landscapes while the remaining two SDAs are in southern Ontario (Table 3, Appendix F).
Climate regulating services
Carbon sequestration is an important global service provided by wetlands. Peatlands for example, help mitigate the release of greenhouse gases such as methane into the atmosphere by storing carbon as organic matter in the ground. With permafrost melt occurring as a result of climate change, these peatlands may begin to emit greenhouse gases instead of storing carbon, reversing some of the climate regulating services that they are currently providing. 70
Significant amounts of peatlands are present in the SDAs surrounding the Hudson Bay Lowlands, northern Alberta, central Manitoba, the Northwest Territories and parts of Newfoundland and Nova Scotia (Table 1, Appendix F). Within the Hudson and James Bay Lowlands, a region along the south and west of Hudson and James Bay, peatlands cover a continuous area of approximately 290,000 km2 to 325,000 km2. 71 , 72 , 73 , 74
Recreation and education services
SDAs along the Windsor to Québec City corridor and across the southern Prairies have been highly modified from their natural state. Agriculture area accounts for over 74% of the land area in 12 of these SDAs, while six SDAs have among the highest proportions of settled area in the country (Table 3, Appendix F). As well, the number and size of wetlands has decreased over time. 75 , 76 The predominance of modified landscapes, combined with decreases in the number and size of wetlands, affects the availability of nature-based educational and recreational opportunities.
Remaining wetlands, such as those of Point Pelee National Park and Rondeau Provincial Park located in the relatively densely populated Northern Lake Erie–02G SDA in southern Ontario, take on added value due to the scarcity of wetlands and natural landscapes in neighbouring areas. Both parks and their surrounding communities benefit from the economic activity of people travelling to and using the parks for recreational and educational services such as bird watching and hiking.
Focus area: Assiniboine-Red drainage region
The Assiniboine-Red drainage region is located in the south central and southeastern portion of the Prairies (Map 3.16). The landscape of the Assiniboine-Red drainage region has been highly modified by agricultural activities. In 2011, it supported a population of 1.47 million people (Table 2, Appendix F) and over 34,400 farms. 77 The drainage region includes the Assiniboine-05M, Souris-05N, Qu’Appelle-05J and the Canadian part of the Red River-05O SDAs, all of which drain into Lake Winnipeg. These four SDAs are among the most modified landscapes in Canada with over 75% of the landscape used for agriculture. Parcel sizes of natural landscapes are among the smallest in Canada, while the distances to natural landscapes are among the largest in the country. To put this in perspective, a person in the Qu’Appelle would have to walk 1.3 km on average before finding a natural land area greater than 250 m2.
Wetlands cover between 10% and 20% of the Assiniboine-Red landscape (Table 1, Appendix F), although the region also includes many small pothole wetlands that are not easily measured and are therefore largely excluded from the estimate. 78 In this region many wetlands have been and continue to be lost through drainage and conversion to agricultural land. For example, between 1968 and 2005, 21% of wetland area in the Broughton’s Creek watershed in Manitoba was degraded or lost due to drainage activities. 79
Various regional and local studies have demonstrated that wetlands in the Assiniboine-Red drainage region provide various EGS including streamflow and water quality regulation, soil retention and formation and habitat provision. Findings from these studies are detailed below.
Streamflow regulating services
The Assiniboine-Red drainage region had the highest variability in water yield—an estimate of renewable freshwater—in Canada for the period from 1971 to 2004. 80 The Missouri, Souris River, Battle and Qu’Appelle SDAs have high variability of streamflow and experience recurrent flooding (Table 3, Appendix F). Extreme flows, both high and low, are important concerns, and the region has had several large floods including the 1995 and 2011 floods on the Assiniboine River and the 1997 and 2007 floods on the Red River.
Between 1968 and 2005, the total number of wetlands in the Broughton’s Creek watershed in the Little Saskatchewan sub-sub-drainage area decreased by 70% as a result of drainage and degradation, resulting in an 18% increase in peak flows following rainfall and a 30% increase in streamflow. 81
Water quality regulating services
Water quality is a major concern in the Assiniboine-Red drainage region due to the level of nutrients such as phosphorous and nitrogen. 82 SDAs in the southern part of the Prairies, including those draining from the United States, contribute to the quantity of nutrients entering Lake Winnipeg. For example, SDAs in this drainage region have some of the largest percentages of land area where fertilizer is applied compared to other areas of the country (Table 3, Appendix F). Because the extent of wetland area is relatively low in these SDAs compared to many other parts of the country, the value of these scarce wetlands and the demand for their water quality regulating services should be relatively high.
Soil retention and formation services
In 2011, the highest turbidity readings in Canada for surface waters supplying drinking water plants were found in the Prairies, including the Assiniboine-Red drainage region. 83 While high turbidity readings may not be representative of all water bodies in the Assiniboine-Red drainage region, the data emphasize the value of and demand for water quality regulating services provided by wetlands.
Habitat provision services
There is high demand for habitat provision services in the Assiniboine-Red drainage region as there are extensive agricultural areas and fragmented natural landscapes. While prairie potholes represent only 10% of the continent’s waterfowl breeding area, they produce half of North America’s waterfowl in an average year. 84 A study of small wetlands in the Tobacco Creek watershed has shown that restoration can be an efficient and cost effective means for establishing habitat, particularly for waterfowl and water quality improvements. 85
Comparing the supply or extent of wetlands to the many demands for their services can help demonstrate the value of wetland EGS. In the case of the Assiniboine-Red drainage region, the many demands for wetland EGS relative to the low supply of wetlands illustrates how the value of wetland EGS in this drainage region could be considered among the highest in Canada.
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