Skip booklet index and go to page content

Prairies Ecozone+ Evidence for Key Findings Summary

Key Findings at a Glance: National and Ecozone+ Level

National and Ecozone+ Level

Table 2 presents the national key findings from Canadian Biodiversity: Ecosystem Status and Trends 2010Footnote3 together with a summary of the corresponding trends in the Prairies Ecozone+. Topic numbers refer to the national key findings in Canadian Biodiversity: Ecosystem Status and Trends 2010. Topics that are greyed out were identified as key findings at a national level but were either not relevant or not assessed for this ecozone+ and do not appear in the body of this document. Evidence for the statements that appear in this table is found in the subsequent text organized by key finding. For many topics, additional supporting information can also be found in the full Prairies Ecozone+ Status and Trends Assessment.Footnote4 See the Preface on page i.

Table 2. Key findings overview

2.1 Theme : Biomes
Themes and topicsKey findings: NationalKey findings: Prairies Ecozone+
1. ForestsAt a national level, the extent of forests has changed little since 1990; at a regional level, loss of forest extent is significant in some places. The structure of some Canadian forests, including species composition, age classes, and size of intact patches of forest, has changed over longer time frames.Forests cover a small proportion of the Prairies Ecozone+ (1–5%). Between European settlement and the 1960s, tree cover expanded into grasslands in many parts of the Aspen Parkland Ecoregion, due in part to changes in the fire regime. Nevertheless, no changes in vegetation zones were detected. Between 1941 and 1981, tree cover in agricultural areas declined from 10 to 3%. From 1985 to 2001, there was a further 6% decline in naturally treed habitat but a 3% increase in tall shrubs. Variability in the growth rates of trees has been attributed to drought years and outbreaks of forest tent caterpillars.
2. GrasslandsNative grasslands have been reduced to a fraction of their original extent. Although at a slower pace, declines continue in some areas. The health of many existing grasslands has also been compromised by a variety of stressors.Native grasslands cover less than 25% of the Prairies Ecozone+. An estimated 70% of native vegetation (mostly grasslands) was lost prior to the 1990s. Losses have slowed but not stopped; in some areas, 10% of remaining native grasslands were lost between 1985 and 2001. About 8% of the native rangelands and tame pastures assessed in Alberta and Saskatchewan were considered "unhealthy" as a result of overgrazing and invasion by non-native plants. Grassland birds declined by 35% as a group from the 1970s to 2000s with declines of greater than 60% for several species.
3. WetlandsHigh loss of wetlands has occurred in southern Canada; loss and degradation continue due to a wide range of stressors. Some wetlands have been or are being restored.Wetlands cover 3% or less of the Prairies Ecozone+. Estimates of historic wetland loss varied from 40 to 71%, depending on the region. At the ecozone scale+, 6% of wetland basins were lost between 1985 and 2001. Wetland drainage and filling remains an ongoing ecological stress, with impacts to continental waterfowl populations.
4. Lakes and riversTrends over the past 40 years influencing biodiversity in lakes and rivers include seasonal changes in magnitude of stream flows, increases in river and lake temperatures, decreases in lake levels, and habitat loss and fragmentation.Water availability is an important driver and issue in this ecozone+, with potential impacts to crop production, rangeland productivity, and wetland conditions for waterfowl. Between the 1940s and 2005, spring melt shifted earlier and seasonal (March–October) runoff volume and peak flows decreased. Average flow declined in several Prairie rivers over the past 50 to 100 years. Water levels in closed-basin lakes declined by four to ten metres from the 1920s to 2006. Construction of large dams peaked between the 1950s and 1970s and fragmentation of river and lake systems continues through small drainage and water control projects.
5. CoastalCoastal ecosystems, such as estuaries, salt marshes, and mud flats, are believed to be healthy in less-developed coastal areas, although there are exceptions. In developed areas, extent and quality of coastal ecosystems are declining as a result of habitat modification, erosion, and sea-level rise.Not relevant
6. MarineObserved changes in marine biodiversity over the past 50 years have been driven by a combination of physical factors and human activities, such as oceanographic and climate variability and overexploitation. While certain marine mammals have recovered from past overharvesting, many commercial fisheries have not.Not relevant
7. Ice across biomesDeclining extent and thickness of sea ice, warming and thawing of permafrost, accelerating loss of glacier mass, and shortening of lake-ice seasons are detected across Canada's biomes. Impacts, apparent now in some areas and likely to spread, include effects on species and food webs.Lake and river ice break up has become earlier on particular lakes and rivers. Data on ice in the Prairies Ecozone+, however, was limited.
DunesFootnotea1Dunes are a unique biome with a very limited distribution in Canada. As a result, information on dunes was not identified as a nationally recurring key finding nor was it included in one of the other key findings in the national report.3 However, because of their significance to biodiversity in the Prairies Ecozone+, information on dunes is included as a separate ecozone+-specific key finding in this report.Active (unstablized) sand dune habitat declined from 1944 to 1991, although losses varied widely across the landscape. At least five species at risk are threatened by alteration of dune habitat.
2.2 Theme: Human/Ecosystem Interactions
Themes and topicsKey findings: NationalKey findings: Prairies Ecozone+
8. Protected areasBoth the extent and representativeness of the protected areas network have increased in recent years. In many places, the area protected is well above the United Nations 10% target. It is below the target in highly developed areas and the oceans.Total area protected increased from between 0.4 and 3.8% in 1992 to 4.5% in 2009. This included 1.2% of the ecozone+ in protected areas classified as IUCN categories I-IV, areas protected for natural and cultural conservation rather than sustainable use by established cultural tradition.
9. StewardshipStewardship activity in Canada is increasing, both in number and types of initiatives and in participation rates. The overall effectiveness of these activities in conserving and improving biodiversity and ecosystem health has not been fully assessed.Stewardship programs and initiatives, particularly those aimed at farmers and ranchers, grew rapidly in the 1990s and 2000s. The National Environmental Farm Plan Initiative and Habitat Stewardship Program for Species at Risk have helped to encourage stewardship activities on private lands. In 2007, approximately 90% of the land under conservation easements in Canada was in the Prairies Ecozone+. Under the Prairie Habitat Joint Venture, winter wheat seeding, which reduces disturbance and provides cover for early-nesting waterfowl species, increased over 600% from 1992 to 2007.
Ecosystem conversionFootnotea1Ecosystem conversion was initially identified as a nationally recurring key finding and information was subsequently compiled and assessed for the Prairies Ecozone+. In the final version of the national report,Footnote3 information related to ecosystem conversion was incorporated into other key findings. This information is maintained as a separate key finding for the Prairies Ecozone+.Approximately 70% of the ecozone+ has been converted, mainly due to agriculture since European settlement. Wetlands, grasslands, and treed habitats all declined between 1985 and 2001.
The landscape is highly fragmented and most remaining natural habitat fragments are less than 10 ha in size. Roads and infrastructure associated with energy development continue to increase fragmentation of the landscape.
10. Invasive non-native speciesInvasive non-native species are a significant stressor on ecosystem functions, processes, and structure in terrestrial, freshwater, and marine environments. This impact is increasing as numbers of invasive non-native species continue to rise and their distributions continue to expand.Both numbers of invasive species and their geographic extent have increased. Native grasslands have been particularly altered by invasive non-native plants, with up to 95% non-native biomass in some areas. Non-native grasses and forbs have reduced native grassland diversity and cover and altered habitat for birds and species at risk. Aquatic ecosystems are also seriously threatened by invasive non-native fish, invertebrates, and plants.
11. ContaminantsConcentrations of legacy contaminants in terrestrial, freshwater, and marine systems have generally declined over the past 10 to 40 years. Concentrations of many emerging contaminants are increasing in wildlife; mercury is increasing in some wildlife in some areas.Herbicides use on agricultural land and the area treated increased rapidly from 1971 to 2006. Measurable pesticide residue was found in 92% of sampled wetlands in the Aspen Parkland Ecoregion in 2002. No data on contaminants in wildlife is included at this time.
12. Nutrient loading and algal bloomsInputs of nutrients to both freshwater and marine systems, particularly in urban and agriculture-dominated landscapes, have led to algal blooms that may be a nuisance and/or may be harmful. Nutrient inputs have been increasing in some places and decreasing in others.Eutrophication in lakes and rivers accelerated in the 20th century due to increased phosphorus and nitrogen inputs. Risk of residual soil nitrogen on agricultural land, however, remains the lowest in Canada and phosphorous levels in some rivers declined in response to improved sewage treatment.
13. Acid depositionThresholds related to ecological impact of acid deposition, including acid rain, are exceeded in some areas, acidifying emissions are increasing in some areas, and biological recovery has not kept pace with emission reductions in other areas.Not considered to be a concern for this ecozone+
14. Climate changeRising temperatures across Canada, along with changes in other climatic variables over the past 50 years, have had both direct and indirect impacts on biodiversity in terrestrial, freshwater, and marine systems.From 1950 to 2007, spring temperature increased by 2.3°C and winter precipitation decreased by 18%. The number of days with snow cover decreased by 16 days. The growing season ended 6 days earlier and trembling aspen flowered 26 days earlier between 1901 and 1997. Some migratory bird species have shown earlier arrival dates of between 0.6 and 2.6 days per degree temperature increase.
15. Ecosystem servicesCanada is well endowed with a natural environment that provides ecosystem services upon which our quality of life depends. In some areas where stressors have impaired ecosystem function, the cost of maintaining ecosystem services is high and deterioration in quantity, quality, and access to ecosystem services is evident.Ecosystem services in the Prairies include water, crop pollination, and nutrient cycling which are necessary for food production and potable water. Important provisioning services include traditional food, fish, and wildlife. The majority of primary productivity is now being used for crop production, impairing the ability of ecosystems to deliver some of these services. Ecosystem services have not been systematically quantified for their economic value, although natural capital in the Upper Assiniboine River Basin was valued in 2004.
2.3 Theme: Habitat, Wildlife, and Ecosystem Processes
Themes and topicsKey findings: NationalKey findings: Prairies Ecozone+
16. Agricultural landscapes as habitatThe potential capacity of agricultural landscapes to support wildlife in Canada has declined over the past 20 years, largely due to the intensification of agriculture and the loss of natural and semi-natural land cover.In 1986, 1996, and 2006, wildlife habitat capacity was low or very low on over 80% of the agricultural landscape (which covers 93% of the ecozone+). From 1986 to 2006, wildlife habitat capacity on the agricultural landscape was constant on 92% of agricultural land, increased on 5%, and decreased on 3%. The dominance of cultivated land and the relatively small proportion of higher value habitat types was the primary reason for the low overall habitat capacity.
17. Species of special economic, cultural, or ecological interestMany species of amphibians, fish, birds, and large mammals are of special economic, cultural, or ecological interest to Canadians. Some of these are declining in number and distribution, some are stable, and others are healthy or recovering.Historic land conversion and human persecution has resulted in declines of many species including birds, freshwater fish, ungulates, and other mammals. Some species, including pronghorn, moose, and several raptors have recovered. Significant declines in grassland and open habitat birds and shorebirds have continued since the 1970s. In constrast, populations of some birds (e.g., Canada geese) have increased rapidly over the same period. Range shifts have been found for some ungulates as a result of changes in competition, tree cover, and hunting pressure.
18. Primary productivityPrimary productivity has increased on more than 20% of the vegetated land area of Canada over the past 20 years, as well as in some freshwater systems. The magnitude and timing of primary productivity are changing throughout the marine system.From 1985–2006, primary productivity, as measured by the Normal Difference Vegetation Index (NDVI), increased for 157,491 km2 (35.1%) and decreased for 1,116 km2 (0.2%; in southeastern Alberta) of the Prairies. NDVI in this ecozone+ is affected by precipitation and land cover change, thus the increasing trend is complicated by drought years and the large proportion of land area in cropland in which changes in cropping practices affect index and trend.
19. Natural disturbanceThe dynamics of natural disturbance regimes, such as fire and native insect outbreaks, are changing and this is reshaping the landscape. The direction and degree of change vary.Historically, the main agents of natural disturbance were fire, drought, heavy grazing, and insect infestations. Fire suppression and human-caused changes to the landscape resulted in a decline in fire leading to woody invasion of some grasslands. However, grassland productivity may have increased as a result. Outbreaks of two major insects, grasshoppers and forest tent caterpillar, were tied to warm, dry summers. Defoliation due to forest tent caterpillar increased in the 1980s and 1990s compared to the 1940s to 1970s.
20. Food websFundamental changes in relationships among species have been observed in marine, freshwater, and terrestrial environments. The loss or reduction of important components of food webs has greatly altered some ecosystems.Patchy, variable grazing by free-roaming bison herds has been replaced by more uniform grazing by confined bison herds and domestic livestock. Large predators such as grey wolf and grizzly bear were nearly eliminated leading to an increase in mesopredators, such as coyotes.
Wildlife diseases and parasitesFootnotea1Wildlife diseases and parasites was initially identified as a nationally recurring key finding and information was subsequently compiled and assessed for the Prairies Ecozone+. In the final version of the national report,Footnote3information related to wildlife diseases and parasites was incorporated into other key findings. This information is maintained as a separate key finding for the Prairies Ecozone+.A wide variety of diseases affect wildlife including waterfowl, cervids, rodents, carnivores, and amphibians. Chronic Wasting Disease is a serious threat to wild deer, elk and moose, and has also caused financial losses to game-farm operations. Type-C Botulism is a disease of waterfowl, especially ducks, which favours alkaline wetlands and dry summers. Dutch Elm Disease threatens the wild elm populations in the eastern part of the Prairies Ecozone+, as well as planted elms in most cities.
2.4 Theme: Science/Policy Interface
Themes and topicsKey findings: NationalKey findings: Prairies Ecozone+
21. Biodiversity monitoring, research, information management, and reportingLong-term, standardized, spatially complete, and readily accessible monitoring information, complemented by ecosystem research, provides the most useful findings for policy-relevant assessments of status and trends. The lack of this type of information in many areas has hindered development of this assessment.Biodiversity monitoring and research vary among provinces. Alberta has field monitoring programs for species diversity and rangeland productivity, but comparable programs are lacking in the other provinces. All provinces have targeted surveys for species of special interest and all provinces have Conservation Data Centres that list plant and animal species and maintain data on their occurrences.
22. Rapid change and thresholdsGrowing understanding of rapid and unexpected changes, interactions, and thresholds, especially in relation to climate change, points to a need for policy that responds and adapts quickly to signals of environmental change in order to avert major and irreversible biodiversity losses.Climate change is predicted to lead to increased frequency of drought years, with major implications for agriculture, grassland productivity, and wetlands.
Note of Table 2

This key finding is not numbered because it does not correspond to a key finding in the national report.Footnote3

Return to notea1 referrer of table 2

Top of Page


Footnote 3

Federal, Provincial and Territorial Governments of Canada. 2010. Canadian biodiversity: ecosystem status and trends 2010. Canadian Councils of Resource Ministers. Ottawa, ON. vi + 142 p.

Return to footnote 3

Footnote 4

Thorpe, J. and B.Godwin. 2013. Prairies Ecozone+ status and trends assessment. Canadian Biodiversity: Ecosystem Status and Trends 2010, Technical Ecozone+ Report. Canadian Councils of Resource Ministers. Draft report.

Return to footnote 4