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Hudson Plains 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 2010Reference 3 together with a summary of the corresponding trends in the Hudson Plains Ecozone+ . Topic numbers in this section correspond to the national key findings as described in Canadian Biodiversity: Ecosystem Status and Trends 2010.Reference 3 Topics in grey text were identified as key findings at a national level but were either not relevant or not assessed for this ecozone+ . Key findings that are not relevant to the Hudson Plains Ecozone+ do not appear in the body of this document. Evidence for the statements that appear here are found in the subsequent text organized by key finding and further elaborated on in the full Technical Ecozone+ Report, Hudson Plains Ecozone+ Status and Trends Assessment.Reference 4

Table 2. Key findings overview.
ThemesThemes and topicsKey findings: NationalKey findings: Hudson Plains Ecozone+
Theme: Biomes1. 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.No trends are apparent in the extent of forest cover. Information is insufficient to assess for potential changes in forest structure, including species composition, age class (or time-since-fire), and intactness. No such changes are expected based on minimal anthropogenic disturbance, including harvest, and an effectively natural and apparently unchanged disturbance regime.
Theme: Biomes2. 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.Not relevant
Theme: Biomes3. 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.Information is currently insufficient for analysis of trends in the distribution, extent, or condition of inland wetlands. These wetlands are assumed healthy, with extensive peatlands largely intact, except in limited areas affected by hydroelectric and mining developments.
Theme: Biomes4. 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.The streamflow network is deficient but a reduced total annual volume of freshwater naturally discharged from several rivers is evident over the last four decades, associated with a four day advance in annual peak discharge rate and a decline in peak intensity. Lakes and rivers are relatively undisturbed and assumed to be mostly in good condition overall. However, hydroelectric developments in and around the ecozone+ have affected flow rates and other physical parameters of some rivers and created a large reservoir in the ecozone+ , with impacts on biota. Cumulative effects from these and possible future hydroelectric developments in the watershed is a concern.
Theme: Biomes5. 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.Intense foraging principally by a greatly increased Mid-Continent population of lesser snow goose has resulted in an apparent trophic cascade in this biome, with an associated loss of ~30% of coastal salt marsh vegetation since the 1970s, from Manitoba to James Bay. Additional area is still being damaged. Hydroelectric development that has reduced the discharge of freshwater from some rivers has caused more saltwater intrusion into estuaries with associated impacts on fish communities. Deterioration of eelgrass beds along the eastern James Bay coast is a concern.
Theme: Biomes6. 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.The marine biome is not directly part of the Hudson Plains Ecozone+ , but Ice across biomesand Species of special interest: economic, cultural, or ecologicalillustrate links between sea ice and the ecozone+ ’s climate and polar bears. Other information about the marine ecosystem adjacent to Hudson Plains Ecozone+ can be found in the Arctic-marine Ecozone+ technical and summary reports of the Ecosystem Status and Trends Report (ESTR).Reference 15, Reference 16
Theme: BiomesTundraNote * of Table 2Ecozone+ -specific key findingInformation is insufficient for analysis of trends in the extent or condition of the tundra (including potential treeline shifts) but some damage is occurring to tundra freshwater marshes as an effect of excessive feeding by a greatly expanded lesser snow goose population (see Coastalbiome section above). Some damage is also being caused by operation of wheeled vehicles (tundra buggies/ATVs). The tundra, which reaches its most southerly extent in this ecozone+ , is especially vulnerable to climate change and associated permafrost thaw.
Theme: Biomes7. 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.Sea ice extent in the broader Hudson Bay marine ecosystem has declined 5.3% per decade over the period 1979 to 2006, with decreases evident in all seasons except winter. The annual period of sea ice cover in western Hudson Bay, southern Hudson Bay, and James Bay (areas adjacent to the ecozone+ ) has decreased an average of about three weeks since the mid-1970s. These changes in sea ice are correlated with deteriorations in the polar bear subpopulations that use the ecozone+ . Monitoring data are currently insufficient to assess trends in permafrost but some permafrost degradation is suspected from casual observations, as well as permafrost loss occurring just outside western and eastern ecozone+borders. Data are insufficient for analysis of trends in lake and river ice.
Theme: Human/Ecosystem Interactions8. 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.The amount of protected area has grown from 1939 to the present, most substantially with the addition of Polar Bear Provincial Park in 1970 and Wapusk National Park in 1996. Protected areas now cover 12.8% of the land base, and include two designated Wetlands of International Importance and two new protected areas announced December 2009. Some representation and connectivity gaps remain, particularly in the interior versus the coast.
Theme: Human/Ecosystem Interactions9. 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.Co-management agreements among First Nations and other levels of government are a particularly important type of stewardship initiative in this ecozone+ . Some important new initiatives were recently introduced, including Ontario’s Far North Land Use Planning Initiative and the Eeyou Marine Region Land Claims Agreement . Such initiatives have the capability to have a direct influence at a broad level on conservation of biodiversity values.
Theme: Human/Ecosystem Interactions10. 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.A number of species both non-native and native to Canada have been introduced into the ecozone+ from outside their normal range but their impacts on the ecology of the ecozone+ are not well studied or monitored. Most introduced species are vascular plants (at least 98 species), generally found near villages. A few introduced species of smaller mammals, birds, and fish are also known to be present, with smallmouth bass (a species native to Canada that was introduced outside its normal range) most recently discovered (2008-09). The potential spread of this warm water predatory species as the climate warms is a concern for fish community composition and dynamics.
Theme: Human/Ecosystem Interactions11. 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.Trends in persistent organic pollutants (POPs) in polar bears are variable with some legacy contaminants declining and some newer (emerging) contaminants increasing. Dietary changes linked to a shortening sea-ice season may be affecting the rates at which POPs change in these bears. In contrast, levels of metals in polar bears, including mercury, have not changed since the 1980s. Mercury monitoring in fish has been limited but significant increases were observed following inundation of the Opinaca reservoir in 1980. Methylmercury levels in water declined to pre-impoundment values in ~8-10 years while mercury levels in fish have declined more gradually and are forecast to increase again due to receipt of mercury exported from a recently impounded reservoir upstream, just outside the ecozone+ . Environmental contaminants at former Mid-Canada Line radar sites are a concern but remediation is now in progress for Ontario sites.
Theme: Human/Ecosystem Interactions12. 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.Not considered to be a concern for this ecozone+ . Minimal nutrient inputs and no known algal blooms or related concerns.
Theme: Human/Ecosystem Interactions13. 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+ . No significant concerns with acid deposition at present, although the ecozone+ has some acid-sensitive terrain.
Theme: Human/Ecosystem Interactions14. 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.The few climate stations in the ecozone+ with long-term data show significant trends over the period 1950-2007 for increased mean annual and/or mean seasonal temperatures (winter and/or summer), increased effective growing degree days, decreased total spring precipitation, decreased seasonal days with precipitation (spring or winter), and a decreased proportion of precipitation falling as snow, depending on location. Main impacts associated with the changing climate include: a significantly shorter sea-ice season in Hudson and James bays; deterioration in the polar bear subpopulations that use the ecozone+ ; advancing wildlife phenology; and changing predator-prey interactions involving polar bear. Other early impacts might also be present but are not detectable given a paucity of monitoring. Climate projections forecast a substantial or complete loss of seasonal sea ice in areas adjacent to the ecozone+ and a ~50% or more reduction in continuous permafrost (and complete loss of permafrost that is currently discontinuous or in isolated patches) in the ecozone+ by 2100. Cascading effects on the ecozone+ ’s ecosystems and biota are expected as the ecozone+ ’s defining climatic and edaphic conditions are lost.
Theme: Human/Ecosystem Interactions15. 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.There is no compelling evidence that the capacity of the ecozone+ to supply ecosystem services has deteriorated, based on limited information available for a select set of services examined for the ESTR. Fur harvests continue to decline but this is probably related to market conditions and changes in Aboriginal lifestyle. The ecozone+ ’s climate-regulating services are of notable concern - the ecozone+ is Canada’s largest peatland complex and climate change impacts on carbon storage and cycling there (currently not monitored) may be globally significant.
Theme: Habitat, Wildlife, and Ecosystem ProcessesIntact landscapes and waterscapesNote + of Table 2Intact landscapes and waterscapes was initially identified as a nationally recurring key finding and information was subsequently compiled and assessed for the Hudson Plains Ecozone+ . In the final version of the national report,Reference 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 Hudson Plains Ecozone+.This ecozone+ has the most intact (97% intact, based on a 2006 analysis) or least anthropogenically fragmented landscape of the forested ecozones+ in Canada, with very few linear disturbances (hydroelectricity transmission corridors, winter roads, and two railway lines and one all-season road that connect the ecozone+ to the south). As such, the ecozone+still provides quality habitat for top predator species such as grey wolf, as well as species of national conservation concern such as polar bear, woodland caribou, and wolverine that require large tracts of unfragmented and/or unroaded landscape and are especially vulnerable to human disturbance. Waterscapes (rivers) have experienced some fragmentation by hydroelectric developments but again much less than many other ecozones+ . As such, this ecozone+ still provides much quality, unfragmented habitat important for anadromous fish species and the migratory lake sturgeon (a species of national conservation concern), which tends to be more deeply in decline or extirpated in more developed locales. Development pressure is, however, mounting and cumulative impacts from roads and hydroelectric developments are concerns.
Theme: Habitat, Wildlife, and Ecosystem Processes16. 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.Not relevant for this ecozone+
Theme: Habitat, Wildlife, and Ecosystem Processes17. Species of special interest: economic, cultural, or ecologicalMany 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.Polar bear has declined in body condition (both Southern and Western Hudson Bay subpopulations) and number (Western Hudson Bay subpopulation only). The forest-dwelling ecotype of woodland caribou shows no evidence of range recession or population decline but the migratory forest-tundra ecotype of woodland caribou, and more specifically the Pen Islands (aka Hudson Bay Coastal Lowland) herd, shows eastward range-shift and possible decline. Some migratory bird populations that use the ecozone+ show strong changes in local, seasonal abundance or distribution (for example, semipalmated sandpiper and brant), or otherwise declining populations of continental concern. The increased number and size of discrete lesser snow goose colonies nesting in the ecozone+ is notable. Lake sturgeon is declining in some rivers affected by hydroelectric development.
Theme: Habitat, Wildlife, and Ecosystem Processes18. 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.Increases in primary productivity in this ecozone+ appear much less than for some other areas of Canada. From 1985 to 2006, Normalized-Difference Vegetation Index (NDVI, a measure of gross primary photosynthesis and a proxy for green leaf area based on remote sensing), significantly increased over 4.9% of the land surface and decreased over 0.1% of the land surface. Some increase in primary productivity may also be suggested by observations of increased tree and shrub cover above the treeline near Churchill, Manitoba.
Theme: Habitat, Wildlife, and Ecosystem Processes19. Natural disturbancesThe 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.There is little evidence to suggest that the natural disturbance regime has changed. The large fire (≥ 2 km² ) regime is essentially natural and no trends are apparent since 1980 in its analyzed elements (annual area burned, causes of fire, seasonality and duration of the active fire season, and fire severity index). Information is insufficient to examine trends in native insect outbreaks. Trends in extreme weather events have not been directly examined but rather indirectly using indicators or indices of extreme weather derived from daily temperature and precipitation data. These indices suggest only limited potential change in extreme weather, including increased diurnal temperature range and variability, more warm days (days with daily maximum temperature > 90th percentile), and more summer days (days with daily maximum temperature > 25 °C), depending on location.
Theme: Habitat, Wildlife, and Ecosystem Processes20. 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.Predator-prey cycles are not being monitored and food web structures are otherwise largely unstudied but some changes in food webs are apparent. Loss or serious reduction of important components of the coastal salt marsh food web are evident, reflecting the severe damage that has occurred to these salt marshes since the 1970s. As well, some changes in predator-prey relationships involving polar bear are apparent that are implicated with climate change and associated changes in wildlife phenology.
Theme: Science/Policy Interface21. 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.With certain exceptions such as climate station monitoring and some studies of waterfowl, polar bear (and sea ice in the broader geography), and fish mercury levels in areas affected by hydroelectric development, inventory, monitoring, and research have been episodic and without continuity over the long term. A geographical bias to the available information is also evident, with most information pertaining to coastal versus inland areas. Much of the available information, including Aboriginal traditional knowledge, is also contained in disparate sources of variable accessibility. Enhanced interests in climate change and economic development are currently driving the collection of much new information that will help inform future assessments. Permafrost, hydrology, and carbon flux are particularly notable and important among knowledge gaps but better information is needed on most fronts, including cumulative impacts and climate modelling.
Theme: Science/Policy Interface22. Rapid changes 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.Thresholds and natural ranges of variability are poorly understood. A somewhat anomalous finding for a relatively remote and undisturbed ecozone+ such as this is a substantially damaged coastal biome (see the Coastalbiome section above). As well, sea ice is changing more rapidly than expected, ahead of modelled climate change projections and these changes are correlated with deteriorating polar bear subpopulations. As the sea-ice season shortens, trophic interactions are changing between polar bears and species such as seals and geese. Unexpected interactions are sometimes observed, such as dietary shifts in polar bears amplifying their contaminant levels. These early effects of climate change are a prelude to the major changes expected in this ecozone+ as extent and duration of seasonal sea ice is reduced.

Notes of Table 2

Note * of Table 2

This key finding is not numbered because it does not correspond to a key finding in the national report.Reference3

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Note + of Table 2

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

Return to note + referrer of table 2


Reference 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. Canadian Biodiversity: Ecosystem Status and Trends 2010.

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Reference 4

Abraham, K.F., McKinnon, L.M., Jumean, Z., Tully, S.M., Walton, L.R. and Stewart, H.M. (lead coordinating authors and compilers). 2011. Hudson Plains Ecozone+ status and trends assessment. Canadian Biodiversity: Ecosystem Status and Trends 2010, Technical Ecozone+ Report. Canadian Councils of Resource Ministers. Ottawa, ON. xxi + 445 p.

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Reference 15

Niemi, A., Paulic, J. and Cobb, D. 2010. Ecosystem status and trends report: Arctic marine ecozones+ . DFO Canadian Science Advisory Secretariat Research Document No. 2010/066. Fisheries and Oceans Canada. viii + 66 p.

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Reference 16

DFO. 2010. 2010 Canadian marine ecosystem status and trends report. DFO Canadian Science Advisory Secretariat Science Advisory Report No. 2010/030 (Revised). Fisheries and Oceans Canada. 38 p.

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