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Taiga Shield Ecozone+ Evidence for Key Findings Summary

Key Findings at a Glance : National and Ecozone+ Level

Table 2 presents the national key findings from Canadian Biodiversity: Ecosystem Status and Trends 2010Footnote 3 together with a summary of the corresponding trends in the Taiga Shield Ecozone+. Topic numbers in this section refer to the national key findings in Canadian Biodiversity: Ecosystem Status and Trends 2010.Footnote 3 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. See the Preface on page i.

Table 2. Key Findings Overview

Theme: Biomes
IDTopicsKey findings: nationalKey findings: Taiga Shield Ecozone+
1ForestsAt 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.While there is some evidence of expansion of forests northward and up slopes in the eastern Taiga Shield, most changes observed are in structure and species composition of vegetation within the forest-tundra zone.
2GrasslandsNative 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.Not relevant
3WetlandsHigh 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.No overall trend information. Ponds are increasing in parts of Quebec and Manitoba due to melting of frozen peatlands.
4Lakes 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.Changes in hydrology on unmanaged streams within the Ecozone+ vary. The streams to the west of the Ecozone+ are part of the Mackenzie River Basin, which has, overall, experienced climate-related increases in streamflow, (1970-2000) while much of the drainage to the east is to Hudson and James bays, which have experienced no net change in total freshwater input (1964-2010). Major changes in the seasonal flow patterns of several rivers, especially those draining to James Bay, have resulted from dams and diversions, starting in 1973.
5CoastalCoastal 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.Coastlines are along James and Hudson bays, Ungava Bay, and the Atlantic Ocean. Little information on status and trends in coastal ecosystems was found for this report. The Hudson Bay region is undergoing a high rate of isostatic rebound, meaning that new soil and vegetation zones are forming. Eelgrass beds, formerly extensive along the James Bay coast, declined rapidly in the late 1990s, recovering somewhat to 2011.
6MarineObserved 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
7Ice 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.Frozen peatlands, in the zones of sporadic and discontinuous permafrost in Quebec and Manitoba, are melting fast, with the southern boundary of permafrost landscape features in Quebec having moved north by 130 km in the past approximately 50 years.

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Theme: Human/Ecosystem Interactions
IDTopicsKey findings: NationalKey Findings: Taiga Shield Ecozone+
8Protected 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.In 2009, 7% of the Ecozone+ was protected, almost all through provincial and territorial reserves and parks.
9StewardshipStewardship 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.Aboriginal peoples make up about 60% of the population of the Taiga Shield, and many follow traditional approaches to stewardship. These approaches vary across cultures and regions but have in common systems based on respect for animals and intimate knowledge of the land.
-Ecosystem conversionFootnote [a]Ecosystem conversion was initially identified as a nationally recurring key finding and information was subsequently compiled and assessed for the Taiga Shield Ecozone+. In the final version of the national report,3 information related to ecosystem conversion was incorporated into other key findings. This information is maintained as a separate key finding for the Taiga Shield Ecozone+.The largest land conversion in the Taiga Shield Ecozone+ has been the flooding of land for hydroelectric development in northern Quebec. For the La Grande development, since the 1970s, about 2,000 km2 of lake area and about 11,000 km2 of land were converted to reservoir. About 6,000 km2 of forest was lost due to conversion to reservoir or to land supporting infrastructure. The reservoirs underwent changes in water chemistry, plankton and fish populations, stabilizing after about 10 years. Further land conversion for hydro development is planned.
10Invasive 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.Limited road access and long, severe winters have kept most invasive species out of the Taiga Shield so far. A few species of birds and plants have been found, mainly near Yellowknife.
11ContaminantsConcentrations 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.Legacy contaminants in fish in Great Slave Lake are stable or declining, although mercury has increased (1993-2008). Mercury in fish increased 3 to 8-fold following reservoir creation in the La Grande complex, peaking after 5 to 13 years and returning to background levels 10 to 35 years after flooding.
12Nutrient 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.The main anthropogenic source of nutrient addition to freshwater systems has been hydroelectric development, through flooding and reservoir creation.
13Acid 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+
14Climate 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.Coverage and distribution of climate trend data are poor for this Ecozone+. Temperatures showed increasing trends while precipitation trends were variable; snow cover duration decreased at the 3 stations with measurements. Most obvious ecological impacts are from changes in permafrost in the south and east of the Ecozone+, and changes in hydrology. There are indications of other impacts, for example caribou may be affected by the increase in ice content in snow.
15Ecosystem 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.Provisioning services are important to cash and non-cash economies in the Taiga Shield and to cultures, nutrition and overall well-being. There are instances of deterioration of provisioning services from severe declines in caribou populations, from environmental changes affecting access to fishing and hunting, from contamination of fish by mercury, and from changes in behaviour of wildlife.

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Theme: Habitat, Wildlif, and Ecosystem Processes
IDTopicsKey Findings: NationalKey Findings: Taiga Shield Ecozone+
-Intact landscapes and waterscapesFootnote [a]Intact landscapes and waterscapes was initially identified as a nationally recurring key finding and information was subsequently compiled and assessed for the Taiga Shield ecozone+. In the final version of the national report,3 information related to intact landscapes and waterscapes was incorporated into other key findings. This information is maintained as a separate key finding for the Taiga Shield ecozone+.The Taiga Shield ecozone+ is a largely intact system. At the current rate of human activity, habitat changes are site-specific and local. However, their cumulative footprint is increasing.
16Agricultural 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.Not relevant
17Species 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.Most migratory tundra caribou herds are in decline and one herd (Bathurst) has declined severely in the last few years. Three local populations of boreal caribou in Labrador are declining. Other herds and local populations in the ecozone+ have stable or unknown trends. Some species of waterfowl are in decline in the western Taiga Shield, especially scaup (63% decline since 1970s) and American wigeon, while trends are more stable in the eastern part of the ecozone+. There have been northward range shifts in the western Taiga Shield of several species, including white-tailed deer, coyote and wood bison.
18Primary 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.Remote sensing shows increased greening, with 36% of the land area showing a significant increase from 1986 to 2006 in NDVI, an index of primary productivity.
19Natural 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.The area burned increased from the 1960s until the 1990s and declined in the 2000s. Decadal changes in area burned may be related to large-scale atmospheric oscillations. There is some indication of earlier fire seasons: an increase in May fires from none in the 1960s to 2.4% of fires in the 1990s. Little information was found on insect outbreaks, which are a less significant forest disturbance than fire in this ecozone+.
20Food 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.Population cycles are a strong component of the system. Many species are migratory or at the edges of their ranges, making them vulnerable to pressures in other, more disturbed regions. There is insufficient monitoring to determine trends and to track effects of changes in one group of species on other ecosystem components.

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Theme: Science/Policy Interface
IDTopicsKey Findings: NationalKey Findings: Taiga Shield Ecozone+
21Biodiversity 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.There is little on-the-ground or long-term monitoring of physical systems in the Taiga Shield. The status of a few keystone species (for example, barren ground caribou) is monitored, but little is known about status and trends for most animal and plant species and little is known about resilience to stressors and how many aspects of the ecosystems react to change. Some specific strengths and gaps are identified.
22Rapid 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.Two instances of rapid change are identified: the precipitous decline in at least one population of migratory tundra caribou and the rapid breakdown of permafrost in peatlands of the eastern Taiga Shield.

Footnote Table


This key finding is not numbered because it does not correspond to a key finding in the national report.Footnote 3

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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.

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