Skip booklet index and go to page content

Hudson Plains Ecozone+ Evidence for key findings summary


Theme: Biomes

Key finding 1

Theme Biomes

National key finding

At 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.

The boreal forests of the Hudson Plains Ecozone+ form an important part of the largest intact tract of forest in Canada, which is also considered one of the largest intact forests remaining in the world.Reference 17 However, the Hudson Plains Ecozone+ has a lower proportion and density of forest than many other forested ecozones+ in Canada.Reference9, Reference18 Owing to widespread wet edaphic conditions, forests there are primarily open and often poorly delineated from the many small bodies of water and non-forested wetlands on the landscape. Truly closed forest stands more typically associated with boreal forests are generally confined to better-drained embankments, slopes, flats, and riverbank levees.Reference 19, Reference20 As such, forest productivity in this ecozone+, as reflected in volume per hectare, is low (42 mReference3 /ha) compared to that of the adjacent Boreal Shield and Taiga Shield ecozones+. Reference 21 Overall, forest density decreases from south to north (Figure 2).Reference9, Reference22 On an area basis, coniferous forest types (conifers ≥75% of total) dominate (54.9%) over mixedwood (34.6%), broadleaved (1.1%), and unclassified (9.5%) ones.Reference21 Spruce is the leading genus in 88% of all forest stands.

Figure 2. Forest density in the Hudson Plains Ecozone+ circa 2000, calculated as the percent of forested 30 m² Landsat pixels in each 1 km² analysis unit.
No data are available for Akimiski Island. Forested areas are areas with >10% tree crown cover.
Forest density in the Hudson Plains Ecozone+ circa 2000
Source: Ahern et al., 2011Reference 9
Long description for Figure 1

This map of the Hudson Plains Ecozone+ shows forest density circa 2000, calculated as the percent of forested 30 m² Landsat pixels in each 1 km2 analysis unit. The most densely forested areas are in the southern regions of the Ontario portion of the ecozone+. The least densely forested areas are in the northern portion of the ecozone+ in Manitoba. No data are available for Akimiski Island. Further details can be found in the preceding/next paragraph(s).

Top of Page

Inventory and monitoring information is very limited for forests in this ecozone+, inhibiting the ability to track changes and report on trends.Reference 4 A coarse-scale satellite remote sensing analysis of land cover classes from 1985 to 2005, however, suggests no significant changes are occurring in the extent of forest cover.Reference 9 Overall reductions in forest cover from 1985 to 2005 were small (0.25%) and primarily due to fire, i.e., burned areas that have not yet revegetatedReference9 (see also Natural disturbances on page 63). Given the coarse scale of the analysis, the errors in mapping may, however, be greater than the small amount of change detected. There is also currently little evidence to suggest that the treeline may be moving (see Tundra biome on page 24).

Data are also insufficient to assess trends in forest structure, including: species composition; age class or time-since-fire; and relative intactness. The ecozone+’s forests are, however, also assumed stable in these respects, given an effectively natural and apparently unchanged disturbance regime (see Natural disturbances on page 63) with only minimal anthropogenic disturbance (see Intact landscapes and waterscapes on page 51), including forest harvest. Although commercial forestry is an important industry elsewhere in Canada’s boreal forest (see for example Anielski and Wilson, 2009Reference23 ), it has not been important in this ecozone+, presumably because of the low productivity of its forests, limited existing access to them, and insufficient markets. Currently, only a very small portion at the southern end of the ecozone+ forms part of a forest management unit in Ontario where commercial harvesting may be permitted,Reference24 and planning for potential commercial forestry has been undertaken in the Moose Factory area by the Moose Cree First Nation.Reference25, Reference26 Anthropogenic fragmentation is also very minor, rendering the ecozone+’s forests particularly important for species such as woodland caribou and wolverine that tend to thrive in large tracts of intact and/or unroaded landscape (see Intact landscapes and waterscapes on page 51).

Key finding 3

Theme Biomes

National key finding

High 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.

The Hudson Plains Ecozone+ is considered Canada’s largest wetland complex, and the third largest in the world.Reference27 These extensive wetlands provide critical habitat for many breeding bird populations.Reference 28 Two sites, Southern James Bay Migratory Bird Sanctuaries (comprised of Moose River Bird Sanctuary and Hannah Bay Bird Sanctuary) and Polar Bear Provincial Park (see also Protected areas on page 30), have been designated Wetlands of International ImportanceReference29 because of the staging and breeding habitat these ecosystems respectively provide for geese, dabbling ducks, and tundra swans.Reference 28 Several species of national conservation concern (such as short-eared owl and yellow rail) also use the ecozone+’s inland (freshwater) wetlands.Reference 14, Reference30 Also notable is that a large proportion of wetlands in the Hudson Plains Ecozone+ are peat-forming wetlands (bogs and fens), making this ecozone+ Canada’s largest peatland complex and the second largest at northern latitudes (>40-50º ).Reference 31 As such, the ecozone+’s peatlands contribute significantly to global carbon-cycling and climate regulation (see Climate regulation, a regulating ecosystem service on page 49).

Although there has been high loss of wetlands in southern Canada, there are few documented changes or trends in the distribution, extent (expansions or contractions), or condition of wetlands in the Hudson Plains Ecozone+, albeit these wetlands are for the most part not being monitored. The ecozone+’s wetlands are assumed healthy with extensive peatlands largely intact, with a few notable exceptions where changes have occurred.

The most important documented change in the ecozone+’s wetlands is in the coastal biome, where about one-third of the coastal salt marsh vegetation from Manitoba to James Bay has been destroyed, and additional areas damaged, as a result of overuse by overabundant lesser snow geese (see Coastalbiome on page 20). However, the phenomenon is also occurring to some extent in the freshwater marshes and fens of the adjacent tundra biome, as a decrease of preferred salt marsh forage forces the geese to move inland to nest and feed (see Tundrabiome on page 24).

Other known stressors of wetlands in the ecozone+ include hydroelectric and mining developments, both of which may cause loss of wetlands or alter wetland classes. Where river flows in the ecozone+ have been reduced by hydroelectric development (for example, Eastmain and Opinaca rivers, see Lakes and rivers on page 16), some desiccation has occurred downstream with, for example, shrubby species expanding at the expense of pioneer wetland species.Reference 32 Conversely, some wetlands in the ecozone+ were affected by flooding in 1980Reference32 when waters diverted from the Eastmain and Opinaca rivers flooded 740 km² of land at the northeast edge of the ecozone+ to create the 1,040 km² Opinaca reservoir that is part of the La Grande hydroelectric complex that continues to the north (see Taiga Shield Evidence for Key Findings SummaryReference33 for further discussion).Reference34 Diversion in 2009 of 72% of the mean annual flow of the Rupert River north to the La Grande complex is further changing wetland hydrology in the Quebec portion of the ecozone+.Reference35

The ecozone+’s only active mine, the Victor open-pit diamond mine (90 km west of the mouth of the Attawapiskat River) was constructed beginning in 2006, opened in 2008,Reference36 and is expected to operate for at least 12 years.Reference37 Although the mine occupies a relatively small area of the ecozone+ (~28.8 km² in direct project-related developmentsReference37), the potential area affected by it, like other mining operations, is considerably larger than the mine itself. As well, although a reclamation plan is in place for the mine,Reference38 some activities associated with the mine can adversely affect the ecozone+’s wetlands to the extent that areas will not be restorable.Reference 37 Wetlands are being impacted by dewatering (potentially affecting an area up to ~500 km² Reference39), as well as infilling during development of mine infrastructure; replacement with mineral stockpiles; and drainage interruption around stockpiles.Reference 37 Some wetlands have also been altered through construction of winter roads and transmission lines from Attawapiskat.

Additional resource developments (see Intact landscapes and waterscapes on page 51) and especially climate change (see Climate change on page 42) are notable future concerns for the ecozone+’s wetlands. Although climate-related changes in the extent of inland (freshwater) wetlands are generally not apparent in this ecozone+, a long-term change or trend involving partial degradation and conversion of frozen peat plateau bogs to fens is suggested in an area from the Nelson River north to Churchill.Reference40

Key finding 4
Lakes and rivers

Theme Biomes

National key finding

Trends 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.

No clear trends in overall river-flow and lake-level regimes (for example, magnitude, frequency, timing, duration, and flashiness of low and high flow events) are evident for undeveloped waters in the Hudson Plains Ecozone+, albeit this result is based on data from only two reference hydrometric stations with data judged useful for this analysis.Reference10 Indeed, the Hudson Bay basin has one of the most deficient streamflow networks in Canada.Reference41 Reduced total annual volume of freshwater naturally discharged from several of the ecozone+’s rivers is, however, indicated in studies of the broader Hudson Bay region.Reference42-Reference44 These trends for reduced total volume of freshwater discharged (1964 to 2000 or 2003), disregarding rivers with hydroelectric development or correcting for them, are correlated with large-scale climate oscillationsReference42 and associated with a four day advance in annual peak discharge rate and a decline in peak intensity.Reference43

Lakes and rivers in the ecozone+ are relatively undisturbed and generally assumed to be in good condition overall. However, hydroelectric developments have affected flow rates and other physical parameters of some rivers and created a large reservoir (Opinaca) in the ecozone+, along with associated impacts on biota (see below). Monitoring is mostly limited to these hydroelectric developments, while the remoteness of most of the area’s hundreds of rivers/streams and tens of thousands of small lakes and ponds precludes a comprehensive survey of their component fish communities.Reference14, Reference45 Portions of the Hudson Plains Ecozone+ are, however, recognized as supporting among the highest diversity of freshwater fish species in Canada.Reference 46, Reference47


Rivers in the Hudson Plains Ecozone+ are typically shallow, slow moving, and have cut deeply into the clay and alluvial sediments.Reference 48 The ecozone+ is drained by twelve major rivers: the Churchill, Nelson, and Hayes rivers in Manitoba; the Moose, Albany, Attawapiskat, Winisk, and Severn rivers in Ontario; and the Harricana, Rupert, Eastmain, and Nottaway rivers in Quebec. The large quantities of nutrients and organic material carried by these rivers make the coastal zone (see Coastalbiome on page 20), and especially the river deltas, very productive for fish and wildlife.Reference47 As well, the large volume of freshwater they discharge dilutes the saltwater in Hudson and James bays to a salinity one-third that of normal oceanic water,Reference49 which in turn allows this inland sea to freeze over completely each year (see Sea ice on page 26).

Hydroelectric developments are currently the principal direct human influence on rivers in this ecozone+ (but mining near Attawapiskat is having smaller-scale effectsReference37). The few hydroelectric developments located within the ecozone+ are near the southern boundaries, concentrating downstream effects within the lowlands (Figure 3). Two hydroelectric generating complexes (Long Spruce, established 1976-77; and Limestone Rapids, established 1989) are located along the Nelson River and one generating station (Otter Rapids, established 1961) is located on the Abitibi River (a tributary of the Moose River). Development in the eastern portion of the ecozone+ includes a complex of eight sites associated with the Eastmain River and Opinaca reservoir (established 1979-80), as part of the La Grande hydroelectric complex. After waters from the Eastmain River and its tributary, the Opinaca River, were diverted to the more northerly La Grande River, flows of the Eastmain River (at its mouth into James Bay) and the confluencing Opinaca River were reduced by 90% and 87%, respectively.Reference32, Reference 34

Figure 3. Spatial distribution of dams (>10 m height) in the Hudson Plains Ecozone+ as of 2005, grouped by decade of completion.
Spatial distribution of dams
Source: adapted from Monk and Baird, 2011Reference10 using data from the Canadian Dam Association, 2003Reference50 updated to 2005
Long description for Figure 3

This map of the Hudson Plains Ecozone+ shows the spatial distribution of dams (>10 m height) as of 2005 grouped by decade of completion. In the western part of the ecozone+, two dams were completed along the Nelson River, one in the 1970s and one in the 1980s. In the southeastern part of the ecozone+, one dam was completed in the 1960s on the Abitibi River (a tributary of the Moose River). Development in the eastern portion of the ecozone+ includes a complex of eight sites associated with the Eastmain River and Opinaca reservoir completed in the 1970s and 1980s. Further details can be found in the preceding/next paragraph(s).

Top of Page

In addition to altering river flow rates, hydroelectric developments have altered the magnitude and timing of fluctuations in river flows. For example, post-development studies ~50 km downstream of the Otter Rapids generating station (Abitibi River) reported diurnal water level fluctuations of 0.7-0.9 m in summer and dewatering of one-third to one-half of the river channel during low flows.Reference51 The effects of water level fluctuations at this station are still apparent at least 75 km downstream.Reference52

Rivers in the Hudson Plains Ecozone+ are also influenced by hydroelectric developments upstream, within adjacent ecozones+. Diversion of water from the Churchill River to the Nelson River is noteworthy, as it reduced the flow of the Churchill River into Hudson Bay by about 40%.Reference53 The recent (2009) diversion of 72% of the mean annual flow of the Rupert River north to the La Grande hydroelectric complexReference35 is likewise noteworthy (though lateral flow from tributaries increases the flow at the river mouth to ~48%). Overall, river channel fragmentation and/or flow regulation have strongly affected the Churchill and Nelson river systems in Manitoba, the Moose River system in Ontario, and the Eastmain and Rupert river systems in Quebec.Reference 35, Reference54 The Albany River in Ontario and Nottaway River in Quebec are systems that are considered moderately affected.Reference54

The hydroelectric developments in and around the ecozone+ (described above) are associated with changes in river biota. Lake sturgeon in the northwestern part of the ecozone+ is assigned an elevated “at risk” status category by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) due in part to hydroelectric development (see Lake sturgeon on page 61). Changes in fish habitat and community composition, including a loss in dominance of lake sturgeon, have also occurred in the reduced flow portions of the Eastmain and Opinaca riversReference 34 (see also the estuary and near-shore impacts in the Coastalbiome on page 20). Fish species composition also did not fully recover following impoundment of the Opinaca reservoir in 1980, even though total fishing yield stabilized by 1996 to levels near baseline.Reference34 An additional concern with this reservoir has been the mobilization of mercury and its subsequent bioaccumulation and contamination of fish (see Contaminants on page 38). Impacts on benthic macroinvertebrate communities are also evident, as in the Abitibi River downstream of the Otter Rapids generating station.Reference52

Although construction of hydroelectric facilities appears to have peaked in the ecozone+ in the late 1970s to early 1980s,Reference10 a high potential exists for more. At least one additional development is proposed for the Nelson River.Reference55, Reference56 In Ontario, seven of the 15 new hydroelectric developments included in the Ontario Power Authority’s supply mix plan for development by 2025 are in the ecozone+, along Abitibi (4), Albany (2), and Moose (1) rivers.Reference57 Additional hydroelectric developments are also either in progress or being considered in Quebec.Reference35, Reference58 Cumulative impacts from multiple hydroelectric developments in the Hudson Bay watershed is an ongoing concern.Reference59,Reference60.Reference61,Reference62,Reference63


The Hudson Plains Ecozone+ contains a multitude of mostly shallow bog lakes and ponds that freeze to the bottom in winter, but some larger lakes are deep enough that they do not freeze to the bottom and can, therefore, support fish communities.Reference40, Reference64Reference65Reference66 Owing to remoteness and limited harvest, fish populations in these lakes are assumed to be generally healthy overall, despite insufficient monitoring.Reference45

Information on trends in water levels, water temperature, and water quality is not available for most natural lakes in this ecozone+. However, observations from thermal monitoring of Hawley Lake are notable from the perspective of unusual warming and fish kills (Hawley Lake is one of four lake trout lakes located near the Sutton Ridges). During the unusually warm summer of 2001, Hawley Lake showed strong and unusual thermal stratification, with temperatures exceeding 20°C in the surface layerReference67, Reference68 (Figure 4). Lake trout in the lake were not affected because ample coldwater habitat remained below the epilimnion.Reference67 Warm air temperatures (daily maximums >30°C) combined with the unusual thermal stratification in this headwater lake, however, contributed to a major die-off of anadromous brook trout, as well as white sucker, downstream in the lower reaches of the Sutton River (which drains Hawley Lake) close to its intersection with the Hudson Bay coast.Reference68 Anadromous brook trout summer in the cold ocean but return to spawn and overwinter in cool freshwater rivers and lakes.

Figure 4. Temperature-depth profiles for Hawley Lake in the Hudson Plains Ecozone+, 1976-2001.
In 2001 Hawley Lake showed strong thermal stratification for one of the first times on record, with water temperatures exceeding 20 °C in the surface (discharge) layer.
Temperature-depth profiles for Hawley Lake
Source: reprinted from Gunn and Snucins, 2010 Reference68 (p 82, fig 2) with permission from Springer Science+Business Media
Long description for Figure 4

This line graph shows temperature-depth profiles for Hawley Lake in the Hudson Plains Ecozone+ from 1976 to 2001. During the unusually warm summer of 2001, Hawley Lake showed strong and unusual thermal stratification, with temperatures exceeding 20˚C in the surface layer. Data presented from previous years, 1976, 1977, and 1986, generally follow the same temperature patterns below 15˚C in. Further details can be found in the preceding/next paragraph(s).

Top of Page

Such die-offs of fish during warming events have rarely been recorded within arctic or subarctic watersheds (but see also Hori (2010)Reference69 regarding Aboriginal knowledge of lake whitefish and sucker die-offs in the lower Albany River during a heat wave and period of reduced precipitation in 2005) and it was suggested that this may be among the first of an increasing number of die-offs of vulnerable anadromous stocks that will occur as climate change proceedsReference68 (Climate changeis discussed on page 42). The seasonal sea ice cover in Hudson and James bays moderates the continental climate, but the sea ice season has been shortening (see Sea ice on page 26) and rivers may consequently be warming. Reduced river flows in the region (see earlier) may also contribute to warming.

Key finding 5

Theme Biomes

National key finding

Coastal 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.

New land emerges and vegetation develops continuously along the coastline of Hudson and James bays, as a result of one of the highest rates of isostatic rebound in North America.Reference70 The coastal biome of the Hudson Plains Ecozone+ is dominated by extensive tidal flats, salt marshes, and shallow waters,Reference 5 including some of the largest and best-developed polar salt marshes in the world (i.e., those characterized by the presence of permafrost).Reference71 These salt marsh ecosystems provide important breeding grounds and staging areas for a large number of migratory waterfowl and shorebirds.Reference 72-Reference76 Subtidal eelgrass beds are also an important component of the coastal ecosystem along the Quebec coast in eastern James Bay and in isolated portions of the Ontario James Bay coast.Reference77-Reference79 Eelgrass beds provide feeding grounds and nurseries for coastal fish species and invertebrates, and forage for brant, Canada geese, and ducks.

The Hudson Plains Ecozone+ is an exception to the national key finding that coastal ecosystems tend to be healthy in areas with little development. The coastal-intertidal zone, and in particular its extensive salt marshes, has been under considerable stress over the past four decades, predominantly due to a continuous increase in foraging (grazing and grubbing) by lesser snow goose, but also by increasing Canada goose breeding and moulting populations in this area.

The Mid-Continent population of lesser snow goose, to which individuals migrating through and nesting in both Manitoba and Ontario belong, has greatly increased over the past four decades, by as much as 7% per year,Reference 80 with the adult portion of the population reaching as many as 7 millionReference81 or moreFootnote. The goose population increase is thought to be principally a result of human influences outside the Hudson Plains Ecozone+, including increased supply of agricultural food on wintering grounds (mostly in the southern United States) and along migration routes, declining harvest rate, and the development of refugia.Reference80, Reference83 In many years, especially those with late snow melt and thaw, millions of geese are held up in the Hudson Plains Ecozone+ on their northward journey, exacerbating the impact of their foraging.

Within these grass- and sedge-dominated coastal salt marshes, intensive foraging by the geese has led to vegetation loss, shifts in plant community composition, and exposure and sometimes erosion of sediment. Reference81, Reference 83, Reference84 As snow geese forage with increasing intensity, an apparent trophic cascade occurs wherein swards of their preferred forage species (Puccinellia phryganodes and Carex subspathacea) are replaced by mudflats often devoid of vegetation.Reference 85, Reference86 The trophic cascade is sustained by positive feedbacks. One such feedback involves grubbing in spring, whereby geese uproot large areas of P. phryganodes and C. subspathacea and other species in the salt marshes, fragmenting swards and exposing the edges to secondary effects such as erosion, drying, and hypersalinity. The combined effect of the grubbing and the secondary processes is a reduction in the amount of above-ground vegetative matter. The second feedback involves grazing during the nesting season and following hatch. The remaining sward area, both intact and fragmented, is grazed more intensively by ever larger numbers of geese, allowing for less compensatory growth, and eventual exhaustion of the plants. The end result is an alternate stable state, wherein large areas of exposed sediments are resistant to re-colonization (Figure 5) because few plants can germinate or establish in the saline sediments. The effects are long-lasting when foraging pressure continues and recovery can take decades.Reference81 In some cases, the geese have been forced to move inland to freshwater marshes and fens in the adjacent tundra biome to nest and feed due to the scarcity of preferred salt marsh forage (see Tundrabiome on page 24).Reference 83, Reference87

Top of Page

Figure 5. An example of the severe damage caused to coastal salt marsh ecosystems of the Hudson Plains Ecozone+ due to over-feeding by the greatly increased Mid-Continent population of lesser snow goose.
Geese were excluded from the area inside the fence, La Pérouse Bay, Manitoba.

Top of Page

Trends showing increasing area damaged over time are evident from remote-sensing analyses, whereby successive waves of plant community destruction are seen to transform the entire intertidal ecosystem (Figure 6). Similar processes, feeding pressure, and damage to coastal vegetation have been described from Manitoba to James Bay, including Akimiski Island, Nunavut. Approximately one third of the coastal salt marsh vegetation in the ecozone+ has been destroyed by geese since the 1970s and a far greater area will be severely damaged if this intense foraging pressure continues.Reference 88 Not only does the destruction of salt marshes remove important food resources for species that feed directly on the vegetation, it also reduces suitability of the zone for other bird species dependent on these habitats for nesting and foodReference 89, Reference90 (see also Food webs on page 66).

Figure 6. Normalized-difference vegetation index (NDVI) analysis of Landsat imagery showing areas with vegetation loss from goose foraging at La Pérouse Bay, Manitoba, for three successive periods between 1973 and 2000.
Normalized-difference vegetation index
Source: reprinted from Jefferies et al., 2006Reference81 (p 238, fig 3) with permission from Blackwell Publishing Ltd.
Long description for Figure 6

This map shows normalized difference vegetation index (NDVI) analysis of Landsat imagery showing areas with vegetation loss from goose foraging at La Pérouse Bay, Manitoba for three successive periods between 1973 and 2000. The majority of change to plant communities happened between 1973 and 1984, along the entire coast, with the exception of a small stretch on the inside of the bay. However, between 1984 and 1993 approximately half that stretch showed damaged plant communities, as well as additional areas all along the coast. Between 1993 and 2000, the last unchanged portion of that stretch showed plant loss, and once again other sections throughout the coast were damaged. Further details can be found in the preceding/next paragraph(s).

Top of Page

Changes in overland river flow and associated nutrient and sediment loads that result from hydroelectric developments in and around the Hudson Plains Ecozone+ (see Lakes and rivers on page 16) have impacted salinity and other aspects of habitat quality in the interfacing estuarine and marine environments of Hudson and James bays. For example, the 90% reduction in flow at the mouth of the Eastmain River associated with its diversion north to the La Grande River has led to a greater intrusion of saltwater into the Eastmain River estuary with associated impacts on the fish community.Reference34 Marine species (sculpin, Greenland cod, sand lance) now inhabit the saltwater portion of the estuary; although anadromous lake whitefish and cisco still migrate up the estuary in fall to spawn, their overwintering area is smaller due to the saltwater intrusion; and feeding grounds for walleye are now 5 to 10 km further upstream.

In the near-shore environment, hydroelectric development in the broader James Bay region, and particularly the increased flow output from the La Grande River (to which flows from the Eastmain and Opinaca rivers were diverted), has been implicatedReference91 in a steep decline in subtidal eelgrass beds along the eastern James Bay coast.Reference 92, Reference93 Reduced salinity during the major growing period (June and July) and increased duration of ice cover related to reduced salinity were suggested as the major causes of a sudden and precipitous decline in eelgrass health near the La Grande River, while wasting disease, climate change, and isostatic rebound were rejected as major causes.Reference 93

Climate change is an important future threat to the ecozone+’s coastal biome (see Climate change on page 42) but sea-level rise is less of a concern for this ecozone+ than for some other coastal areas (for example, Tsuji et al., 2009Reference 94) due to an especially high rate of isostatic rebound.Reference70 Still, the combined effect of isostatic rebound and sea-level rise could reduce the rate of successional development of coastal systems.


Theme Biomes

Ecozone+ - specific key finding

The tundra in the Hudson Plains Ecozone+ represents the southernmost zone of continuous tundra vegetation and continuous permafrost in North America.Reference14, Reference 76, Reference95, Reference96 It occurs as a series of beach ridges and inter-ridge areas (extensive sedge meadows and fens and shrub-dominated fens), in a band of land contiguous with the inland side of the coastal-intertidal zone, from Churchill, Manitoba to near the Lakitusaki River, Ontario, in the area of continuous permafrostReference97, Reference98 (see Figure 9 in Ice across biomes). The most inland tundra sites comprise a forest-tundra landscape. The defining tree “line” itself has been described as erratic, extending farthest north on river levees and beach ridges where drainage is better and the active layer deeper.Reference 99

Information is insufficient for analysis of trends in extent or condition of the tundra in the Hudson Plains Ecozone+ as a whole. However, a portion of the ecozone+’s tundra, and in particular its freshwater marshes, is being damaged from excessive feeding by a greatly expanded lesser snow goose population (see the Coastalbiome on page 20 for further discussion of snow goose damage). That is, in some cases the geese have so drastically depleted their preferred food sources (P. phyganodes and C. subspathacea) in the coastal salt marshes that they have moved to forage in less desirable areas within tundra freshwater marshes with similarly devastating effects.Reference100, Reference 101 In response to development of hypersaline soils in grubbed areas, Salix sp. shrubs have been reduced as much as 65%,Reference102, Reference 103 resulting, in turn, in declines of tundra-nesting bird populations located close to snow goose colonies.Reference 83, Reference89 Sammler et al., 2008Reference 101 have shown that localized nesting populations of semipalmated sandpipers, dunlins, savannah sparrows, Lapland longspurs, and other tundra-nesting passerines were more frequent in intact sedge meadow habitats than those altered by goose activity. Although no area-wide population effects were reported, it is likely that as degraded areas expand with continued goose foraging, area-wide effects will occur.Reference 101

Damage to plant communities on both the drier beach ridges and wetter inter-ridge areas of the tundra is also being caused by the operation of wheeled vehicles (tundra buggies/ATVs) in ManitobaReference97 and in OntarioReference 104 (Figure 7).

Figure 7. An example of ATV damage to wet tundra, near Fort Severn, Ontario (July 2008).
HBL ATV tracks in wet tundra Ken Abraham 14 July 2008
Photo © Queen’s Printer for Ontario/K.F. Abraham, Ontario Ministry of Natural Resources
Long description for Figure 7

There are several trails and tracks across the landscape.

The tundra, which reaches its most southerly Canadian extent in the Hudson Plains Ecozone+, is especially vulnerable to climate change and associated permafrost thaw (see Climate change on page 42). Currently, there is no strong evidence that the ecozone+’s treeline is moving north (for example, Scott et al., 1987Reference 105), as is occurring in some other northerly locations in Canada and the world (for example, Harsch et al., 2009Reference 106). The treeline in this ecozone+ has, however, received relatively little direct study. Ballantyne (2009)Reference107 recently documented increases of 12.6% and 6.9% of shrub and tree cover, respectively, in a 2.55 km² study area just north of the functional treeline at Churchill. Climate-driven change to the ecozone+’s tundra may also be suggested by a long-term (non-successional) change or trend involving partial degradation and conversion of frozen peat plateau bogs to fens in an area from the Nelson River north to Churchill.Reference40

Key finding 7
Ice across biomes

Theme Biomes

National key finding

Declining 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.

The sea ice in Hudson and James bays is significantly changing. Loss of sea ice is correlated with deteriorations in the polar bear subpopulations that use sea ice as habitat in winter and the terrestrial environment of the Hudson Plains Ecozone+ in summer. On the terrestrial landscape, permafrost degradation is suspected, but cannot currently be confirmed due to insufficient monitoring data. Data are also insufficient for analysis of trends in lake and river ice.

Sea ice

Hudson Bay, along with James Bay to the south and Foxe Basin to the north, is the largest inland sea in the world and the only sea at this latitude that goes through a complete cryogenic (ice) cycle each year.Reference108, Reference 109 This factor has been primary in shaping the ecosystem around it by creating much cooler temperatures than what is typical of this latitude.Reference110 These cooler temperatures provide the conditions necessary to maintain the southernmost continuous permafrost in North AmericaReference95, Reference 96 and support species of arctic affinity, such as polar bear, arctic fox, and some plants, at their southernmost occurrence (see also Polar bear on page 54).Reference99, Reference111, Reference 112

The winter maximum extent of sea ice has not changed, and Hudson and James bays continue to completely freeze over each year. However, sea ice extent in the broader Hudson Bay marine ecosystem declined significantly over the period 1979 to 2006, on the order of -5.3 ±1.1% per decade, with decreases evident in all seasons except winter.Reference 108 As well, significant trends for longer ice-free periods each year have been detected in areas of Hudson and James bays adjacent to the Hudson Plains Ecozone+, associated with later freeze-up dates, earlier break-up dates, or both, depending on location (see inset).Reference109, Reference 113-Reference115 On average, the annual ice-free period in western Hudson Bay, southern Hudson Bay, and James Bay has increased by ~3 weeks since the mid-1970s.Reference 109 These trends in sea ice are correlated with significant negative impacts on polar bear, which is dependent on sea ice as habitat and a platform for hunting and feeding on seals (see Polar bear on page 54for further discussion). These trends in sea ice are projected to continue, such that James Bay and the southern portion of Hudson Bay (i.e., marine areas adjacent to the ecozone+) may become substantially to completely ice-free by 2100 (see Climate change on page 42).

Sea Ice is Changing

Analysis of historical sea ice data for Hudson and James bays reveals that this inland sea is becoming increasingly ice-free. Gough et al., (2004)Reference 115 found significant trends for earlier dates of sea ice break-up in southwestern Hudson Bay over the period 1971 to 2003. Although they did not find a trend in later freeze-up dates, the trend for earlier break-up alone resulted in an approximate increase in ice-free conditions by approximately 0.49 days per year (Figure 8). Subsequent work that expanded the study area to include the entire Hudson Bay region found a significant trend for earlier break-up in James Bay, southern Hudson Bay, and western Hudson Bay with magnitudes ranging from 0.49 to 1.25 days earlier per year, coincident with temperature trends in these areas.Reference109

Figure 8. Trends in a) date of freeze-up and b) date of break-up of sea ice in southwestern Hudson Bay.
Trends in southwestern Hudson Bay
Source: redrawn from Gough et al., 2004 Reference115 (p 303, fig 2) with permission from Arctic Institute of North America. D ata from t he Canadian Ice Service archives
Long description for Figure 8
These two line graphs show the following information:
--Julian Date

Top of Page


The Hudson Plains Ecozone+ supports the most southern continuous permafrost in North AmericaReference95, Reference 96 and includes a full range of permafrost types across its geography (Figure 9). At the northern extent of the ecozone+, continuous permafrost can be found beneath the coastal ridges and wetlands. As little as 20 km inland from the coast in some areas (as near York Factory), the terrain changes to palsas, localized geomorphic mounds indicative of a transition from continuous to discontinuous permafrost. Sporadic discontinuous and isolated patches of permafrost are found further south, while permafrost is absent at the most southerly extent of the ecozone+ in areas away from the coast. The presence of permafrost, and its effective retention of surface water, contributes greatly to the unique nature of this ecozone+ as Canada’s largest wetland complex.

Figure 9. Permafrost zones in and around the Hudson Plains Ecozone+.
Permafrost zones
Source: adapted from Heginbottom et al., 1995Reference116
Long description for Figure 9

This map shows permafrost zones in and around the Hudson Plains Ecozone+. At the northern extent of the ecozone+, continuous permafrost can be found beneath the coastal ridges and wetlands. As little as 20 km inland from the coast in some areas (as near York Factory), the terrain changes to palsas, localized geomorphic mounds indicative of a transition from continuous to discontinuous permafrost. Sporadic discontinuous and isolated patches of permafrost are found further south, while permafrost is absent at the most southerly extent of the ecozone+ in areas away from the coast. Further details can be found in the preceding/next paragraph(s).

Top of Page

Sufficient data are not currently available with which to evaluate trends in the extent and condition of permafrost, or associated shifts in permafrost boundaries, in the Hudson Plains Ecozone+. Until relatively recently, no permafrost thermal monitoring sites were located and maintained there to help track changes as is being done elsewhere in Canada’s north.Reference117, Reference 118 Ten year data are now available for a permafrost site at Churchill, Manitoba,Reference119 a new permafrost monitoring site was established in 2007 at York Factory, Manitoba,Reference 120 and two more sites have recently been added in northern and southern areas of Wapusk National Park, Manitoba.Reference 121 In Ontario, annual summer monitoring of permafrost began in 2007 and a permanent monitoring site (Brant River) is now in place.Reference122

Changes in permafrost, however, are suspected in the Hudson Plains Ecozone+. Both collapse and erosion features and aggrading features are visible in the ecozone+’s permafrost tension zone and collapse features appear to have become more widespread over time, as in the Ekwan to Lake River areas of the northern James Bay coast.Reference 99 In recent decades, casual observations have also been made of slumping and collapse of river banks along the Hayes and Nelson rivers in the vicinity of York Factory, Manitoba, close to the boundary between discontinuous and continuous permafrost. Partial degradation and conversion of frozen peat plateaus to fens, as well as the enlargement of some associated lakes from eroding shorelines, is also suggested in the area from the Nelson River north to Churchill.Reference40 Moreover, although the relatively short 10 year permafrost record from Churchill shows no significant trend to date, comparison of this data with the much longer climate record at Churchill suggests that the air temperature warming there might have resulted in permafrost warming of ~0.5°C since the mid-1970s.Reference119 Permafrost loss is known to be occurring just outside both western and eastern ecozone+ boundaries in areas where permafrost is discontinuous and in isolated patches respectively.Reference123, Reference 124

Modeling for the Hudson Bay region forecasts a loss of ~50% or more of the continuous permafrost and a virtual elimination of a climate that supports permafrost by 2100,Reference95, Reference125 which would have significant impacts on ecozone+ integrity (see Climate change on page 42).

Lake and river ice

Data are insufficient for analysis of long-term trends in river and lake ice in the Hudson Plains Ecozone+.Reference7 For example, trends in break-up dates for the lower Attawapiskat, Albany, and Moose rivers (near the James Bay coast) were inconclusive when examined from disparate community-based data sources.Reference126 It is, therefore, not known from monitoring if trends being observed elsewhere in northern Canada for earlier break-up and in some cases also later freeze-up of freshwater iceReference127-Reference129 are occurring in this ecozone+. Changes in freshwater ice are, however, suspected. Aboriginal peoples in western James Bay have noted changes in the break-up and/or freeze-up of rivers,Reference 126 as well as a reduction in ice thickness both in naturally flowing rivers and rivers with flows modified by hydroelectric developments and longer ice-free periods for some inland lakes.Reference61

Top of Page


Footnote ‡

This population estimate is higher than estimates derived from mid-winter population surveys reported in other references (for example Canadian Wildlife Service Waterfowl Committee 2009,Reference82 referenced in Canadian Biodiversity, Ecosystem Status and Trends 2010). Mid-winter survey estimates are known to largely underestimate total population levelsReference83 and are most useful for examining trends in relative population size over time.

Return to referencereferrer


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.

Return to reference 3 referrer

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.

Return to reference 4 referrer

Reference 5

Ecological Stratification Working Group. 1995. A national ecological framework for Canada. Agriculture and Agri-Food Canada, Research Branch, Centre for Land and Biological Resources Research and Environment Canada, State of the Environment Directorate, Ecozone Analysis Branch. Ottawa, ON/Hull, QC. 125 p. Report and national map at 1:7 500 000 scale.

Return to reference 5 referrer

Reference 7

Zhang, X., Brown, R., Vincent, L., Skinner, W., Feng, Y. and Mekis, E. 2011. Canadian climate trends, 1950-2007. Canadian Biodiversity: Ecosystem Status and Trends 2010, Technical Thematic Report No. 5. Canadian Councils of Resource Ministers. Ottawa, ON. iv + 21 p. Technical Reports.

Return to reference 7 referrer

Reference 9

Ahern, F., Frisk, J., Latifovic, R. and Pouliot, D. 2011. Monitoring ecosystems remotely: a selection of trends measured from satellite observations of Canada. Canadian Biodiversity: Ecosystem Status and Trends 2010, Technical Thematic Report No. 17. Canadian Councils of Resource Ministers. Ottawa, ON. Technical Reports.

Return to reference 9 referrer

Reference 10

Monk, W.A. and Baird, D.J. 2011. Biodiversity in Canadian lakes and rivers. Canadian Biodiversity: Ecosystem Status and Trends 2010, Technical Thematic Report No. 20. Canadian Councils of Resource Ministers. Ottawa, ON. Technical Reports.

Return to reference 10 referrer

Reference 14

Abraham, K.F. and Keddy, C.J. 2005. The Hudson Bay Lowland: a unique wetland legacy. In The world's largest wetlands: ecology and conservation. Edited by Fraser, L.H. and Keddy, P.A. Cambridge University Press. New York, NY. pp. 118-148.

Return to reference 14 referrer

Reference 17

World Resources Institute. 2010. Map of the state of the world's forests.

Return to reference 17 referrer

Reference 18

Wulder, M.A., White, J.C., Han, T., Coops, N.C., Cardille, J.A., Holland, T. and Grills, D. 2008. Monitoring Canada's forests. Part 2: national forest fragmentation and pattern. Canadian Journal of Remote Sensing 34:563-584.

Return to reference 18 referrer

Reference 19

Coombs, D.B. 1952. The Hudson Bay Lowland: a geographical study. Thesis (M.Sc). McGill University. Montreal, QC. 227 p.

Return to reference 19 referrer

Reference 20

Sjörs, H. 1959. Bogs and fens in the Hudson Bay Lowlands. Arctic 12:2-19.

Return to reference 20 referrer

Reference 21

National Forest Inventory. 2010. Unpublished analysis of data by ecozone+ from: Canada's national forest inventory standard reports [online]. Government of Canada. (last accessed March, 2010).

Return to reference 21 referrer

Reference 22

OMNR. 2007. State of the forest report 2006. Ontario Ministry of Natural Resources. Toronto, ON. 32 p. + CD-ROM.

Return to reference 22 referrer

Reference 23

Anielski, M. and Wilson, S. 2009. Counting Canada's natural capital: assessing the real value of Canada's boreal ecosystems. The Canadian Boreal Initiative (Ottawa, ON) and the Pembina Institute (Drayton Valley, AB). 76 p.

Return to reference 23 referrer

Reference 24

OMNR. 2006. Forest resources of Ontario 2006. Forest Information Series. Ontario Ministry of Natural Resources. Toronto, ON. 159 p.

Return to reference 24 referrer

Reference 25

FFTC. 2007. Forestry Futures Trust 2006/07 annual report. Forestry Futures Trust Committee. Thunder Bay, ON. 100 p.

Return to reference 25 referrer

Reference 26

FFTC. 2009. Forest Futures Trust Ontario 2008-2009 annual report. Forestry Futures Trust Committee. Thunder Bay, ON. 15 p.

Return to reference 26 referrer

Reference 27

Fraser, L.H. and Keddy, P.A. (eds.). 2005. The world's largest wetlands: ecology and conservation. Cambridge University Press. Cambridge, UK. 488 p.

Return to reference 27 referrer

Reference 28

Gillespie, D.I., Boyd, H. and Logan, P. 1991. Wetlands for the world: Canada's Ramsar sites. Canadian Wildlife Service. Ottawa, ON. 40 p.

Return to reference 28 referrer

Reference 29

Wetlands International. 2010. Ramsar sites information service [online]. Wetlands International. (last accessed December, 2010).

Return to reference 29 referrer

Reference 30

COSEWIC. 2010. Wildlife species search. Database of wildlife species assessed by COSEWIC [online]. Committee on the Status of Endangered Wildlife in Canada. Database of wildlife species assessed by COSEWIC (last accessed December, 2010).

Return to reference 30 referrer

Reference 31

Tarnocai, C. and Stolbovoy, V. 2006. Northern peatlands: their characteristics, development and sensitivity to climate change. In Peatlands: evolution and records of environmental and climate changes. Edited by Martini, I.P., Cortizas, A.M. and Chesworth, W. Elsevier. Amsterdam, The Netherlands. pp. 17-51.

Return to reference 31 referrer

Reference 32

Hayeur, G. 2001. Summary of knowledge acquired in northern environments from 1970 to 2000. Hydro-Québec. Montréal, QC. 110 p.

Return to reference 32 referrer

Reference 33

ESTR Secretariat. 2011. Taiga Shield Ecozone+ evidence for key findings summary. Canadian Biodiversity: Ecosystems Status and Trends 2010, Evidence for Key Findings Summary Report No. 9. Canadian Councils of Resource Ministers. Ottawa, ON. In press.

Return to reference 33 referrer

Reference 34

Therrien, J., Verdon, R. and Lalumière, R. 2004. Environmental monitoring at the La Grande complex. Changes in fish communities. Summary report 1977-2000. GENIVAR Groupe Conseil Inc. and Direction Barrages et Environnement, Hydro-Québec. Montréal, QC. 129 p. and appendices.

Return to reference 34 referrer

Reference 35

Hydro-Québec. 2010. Eastmain-1-A/Sarcelle/Rupert project. Hydro-Québec. (last accessed December, 2010).

Return to reference 35 referrer

Reference 36

De Beers Canada. 2008. De Beers officially opens two mines in Canada. News release.

Return to reference 36 referrer

Reference 37

De Beers Canada. 2008. De Beers officially opens two mines in Canada. News release.

Return to reference 37 referrer

Reference 38

AMEC. 2004. De Beers Victor Diamond Mine project closure plan, volume 1 - main report. De Beers Canada Inc. Toronto, ON.

Return to reference 38 referrer

Reference 39

AMEC. 2008. Request for amendment to PTTW #5607-78CL4V dated November 26, 2007 and C. of A. 8700-783LPK dated December 11, 2007. Well field dewatering, De Beers Victor mine. Submitted to Ontario Ministry of Environment, Environmental Assessment and Approvals Branch, Toronto, Ontario; and Ontario Ministry of Environment, Northern Region Technical Support Section, Thunder Bay, Ontario. AMEC Earth & Environmental. Mississauga, ON.

Return to reference 39 referrer

Reference 40

Dyke, L.D. and Sladen, W.E. 2010. Permafrost and peatland evolution in the northern Hudson Bay Lowland, Manitoba. Arctic 63:429-441.

Return to reference 40 referrer

Reference 41

Mishra, A.K. and Coulibaly, P. 2010. Hydrometric network evaluation for Canadian watersheds. Journal of Hydrology 380:420-437.

Return to reference 41 referrer

Reference 42

Déry, S.J. and Wood, E.F. 2005. Decreasing river discharge in northern Canada. Geophysical Research Letters 32, L10401, 4 p.

Return to reference 42 referrer

Reference 43

Déry, S.J., Stieglitz, M., McKenna, E.C. and Wood, E.F. 2005. Characteristics and trends of river discharge into Hudson, James, and Ungava Bays, 1964-2000. Journal of Climate 18:2540-2557.

Return to reference 43 referrer

Reference 44

McClelland, J.W., Déry, S.J., Peterson, B.J., Holmes, R.M. and Wood, E.F. 2006. A pan-arctic evaluation of changes in river discharge during the latter half of the 20th century. Geophysical Research Letters 33:L06715.

Return to reference 44 referrer

Reference 45

Browne, D.R. 2007. Freshwater fish in Ontario's boreal: status, conservation and potential impacts of development. WCS Canada Conservation Report No. 2. Wildlife Conservation Society Canada. Toronto, ON. 100 p.

Return to reference 45 referrer

Reference 46

Chu, C., Minns, C.K. and Mandrak, N.E. 2003. Comparative regional assessment of factors impacting freshwater fish biodiversity in Canada. Canadian Journal of Fisheries and Aquatic Sciences 60:624-634.

Return to reference 46 referrer

Reference 47

Abell, R., Thieme, M.L., Revenga, C., Bryer, M., Kottelat, M., Bogutskaya, N., Coad, B., Mandrak, N., Balderas, S.C., Bussing, W., Stiassny, M.L.J., Skelton, P., Allen, G.R., Unmack, P., Naseka, A., Ng, R., Sindorf, N., Robertson, J., Armijo, E., Higgins, J.V., Heibel, T.J., Wikramanayake, E., Olson, D., López, H.L., Reis, R.E., Lundberg, J.G., Pérez, M.H.S. and Petry, P. 2008. Freshwater ecoregions of the world: a new map of biogeographic units for freshwater biodiversity conservation. Bioscience 58:403-414.

Return to reference 47 referrer

Reference 48

Campbell, D., Kwiatkowski, R. and McCrea, R.C. 1986. Benthic communities in five major rivers of the Hudson Bay Lowlands, Canada. Water Pollution Research Journal Canada 21:235-250.

Return to reference 48 referrer

Reference 49

Prinsenberg, S.J. 1982. Present and future circulation and salinity in James Bay. Naturaliste Canadien 109:827-841.

Return to reference 49 referrer

Reference 50

Canadian Dam Association. 2003. Dams in Canada. Montréal, QC. International Commission on Large Dams (ICOLD), CD-ROM.

Return to reference 50 referrer

Reference 51

Stanfield, R., Riley, J. and Mackey, B. 1972. Biological studies of the Onakawana area. Task Force Onakawana Working Paper 3. Ontario Ministry of the Environment. Toronto, ON. 40 p.

Return to reference 51 referrer

Reference 52

Fiset, W. 1998. Response of benthic macroinvertebrate communities downstream of a peaking hydroelectric generation station in northeastern Ontario. NEST Technical Report TR-036. Ontario Ministry of Natural Resources, Northeast Science and Technology Section. South Porcupine, ON. 36 p.

Return to reference 52 referrer

Reference 53

Manitoba Hydro. 2010. Churchill River diversion [online]. Manitoba Hydro. (last accessed December, 2010).

Return to reference 53 referrer

Reference 54

Dynesius, M. and Nilsson, C. 1994. Fragmentation and flow regulation of river systems in the northern third of the world. Science 266:753-762.

Return to reference 54 referrer

Reference 55

Manitoba Hydro. 2010. Conawapa generation station [online]. Manitoba Hydro. (last accessed December, 2010).

Return to reference 55 referrer

Reference 56

Bernhardt, W.J. (North/South Consultants). 2009. Proposed hydroelectric developments on the Nelson River. Personal communication.

Return to reference 56 referrer

Reference 57

OPA. 2007. Supply -- renewable resources. EB-2007-0707, Exhibit D, Tab 5, Schedule 1. Ontario Power Authority. Toronto, ON. 64 p.

Return to reference 57 referrer

Reference 58

Ministère du développement durable, de l'environnement et des parcs. 2010. Projet hydroélectrique Eastmain-1-A et dérivation Rupert (French only). Gouvernement du Québec. (last accessed December, 2010).

Return to reference 58 referrer

Reference 59

Bunch, J.N. and Reeves, R.R.(eds.). 1992. Proceedings of a workshop on the potential cumulative impacts of development in the region of Hudson and James bays, 17-19 June 1992. Canadian Technical Report of Fisheries and Aquatic Sciences 1874:iv + 39 p.

Return to reference 59 referrer

Reference 60

Rosenberg, D.M., Bodaly, R.A. and Usher, P.J. 1995. Environmental and social impacts of large-scale hydroelectric development: who is listening? Global Environmental Change 5:127-148.

Return to reference 60 referrer

Reference 61

McDonald, M., Arragutainaq, L. and Novalinga, Z. (compilers). 1997. Voices from the Bay: traditional ecological knowledge of Inuit and Cree in the Hudson Bay bioregion. Canadian Arctic Resources Committee, Environmental Committee of Municipality of Sanitkiluaq. Ottawa, ON. 98 p.

Return to reference 61 referrer

Reference 62

Arragutainaq, L., Atkinson, M., Hamilton, A.L. and Fleming, M. 2007. Contemplating the transboundary cumulative effects of hydroelectricity developments on the Hudson Bay marine ecosystem. Presentation prepared for Aboriginal Energy Forum. Toronto, ON, December 10-11, 2007. Nunavut Hudson Bay Inter-Agency Working Group, Municipality of Sanikiluaq. Toronto, ON. 26 p.

Return to reference 62 referrer

Reference 63

Sallenave, J.D. (ed.). 1993. Towards the assessment of cumulative impacts in Hudson Bay. A report from the Cumulative Impact Assessment Workshop held in Ottawa, Ontario, May 18-19, 1993. Hudson Bay Programme, Canadian Arctic Resources Committee, Municipality of Sanikiluaq. Ottawa, ON. 41 p.

Return to reference 63 referrer

Reference 64

OMNR. 1985. Moosonee District background information. Ontario Ministry of Natural Resources. Moosonee, ON. 167 p.

Return to reference 64 referrer

Reference 65

Schetagne, R., Therrien, J. and Lalumière, R. 2003. Environmental monitoring at the La Grande Complex. Evolution of fish mercury levels. Summary Report 1978-2000. Direction Barrages et Environnement, Hydro-Québec Production and Groupe conseil GENIVAR Inc. Quebec, QC. 185 p. + appendix.

Return to reference 65 referrer

Reference 66

Duguay, C.R. and Lafleur, P.M. 2003. Determining depth and ice thickness of shallow sub-Arctic lakes using space-borne optical and SAR data. International Journal of Remote Sensing 24:475-489.

Return to reference 66 referrer

Reference 67

Snucins, E. 2003. Hawley Lake survey, August 1 - 8, 2001. Freshwater Ecology Unit. Laurentian University. Sudbury, ON. 13 p.

Return to reference 67 referrer

Reference 68

Gunn, J. and Snucins, E. 2010. Brook charr mortalities during extreme temperature events in Sutton River, Hudson Bay Lowlands, Canada. Hydrobiologia 650:79-84.

Return to reference 68 referrer

Reference 69

Hori, Y. 2010. The use of traditional environmental knowledge to assess the impact of climate change on subsistence fishing in the James Bay region, Ontario, Canada. Thesis (Master of Environmental Studies). University of Waterloo. Waterloo, ON. 81 p.

Return to reference 69 referrer

Reference 70

Sella, G.F., Stein, S., Dixon, T.H., Craymer, M., James, T.S., Mazzotti, S. and Dokka, R.K. 2007. Observation of glacial isostatic adjustment in "stable" North America with GPS. Geophysical Research Letters 34, L02306, 6 p.

Return to reference 70 referrer

Reference 71

Martini, I.P., Jefferies, R.L., Morrison, R.I.G. and Abraham, K.F. 2009. Polar coastal wetlands: development, structure, and land use. In Coastal wetlands: an integrated ecosystem approach. Edited by Perillo, G.M.E., Wolanski, E., Cahoon, D.R. and Brinson, M.M. Elsevier. Amsterdam, The Netherlands. pp. 119-155.

Return to reference 71 referrer

Reference 72

Niles, L.J., Burger, J., Porter, R.R., Dey, A.D., Minton, C.D.T., Gonzalez, P.M., Baker, A.J., Fox, J.W. and Gordon, C. 2010. First results using light level geolocators to track red knots in the western hemisphere show rapid and long intercontinental flights and new details of migration pathways. Wader Study Group Bulletin 117:123-130.

Return to reference 72 referrer

Reference 73

Morrison, R.I.G. and Harrington, B.A. 1979. Critical shorebird resources in James Bay and eastern North America. Transactions of the North American Wildlife Natural Resources Conference 44:498-507.

Return to reference 73 referrer

Reference 74

Ross, R.K. 1982. Duck distribution along the James and Hudson Bay coasts of Ontario. Le Naturaliste Canadien 109:927-932.

Return to reference 74 referrer

Reference 75

Thomas, V.G. and Prevett, J.P. 1982. The roles of the James and Hudson Bay Lowland in the annual cycle of geese. Le Naturaliste Canadien 109:913-925.

Return to reference 75 referrer

Reference 76

Stewart, D.B. and Lockhart, W.L. 2005. An overview of the Hudson Bay marine ecosystem. Canadian Technical Report of Fisheries and Aquatic Sciences 2586:vi + 487.

Return to reference 76 referrer

Reference 77

Curtis, S. 1973. The Atlantic brant and eelgrass (Zostera marina) in James Bay, a preliminary report. James Bay report series No. 8. Canadian Wildlife Service. Ottawa, ON. 8 p.

Return to reference 77 referrer

Reference 78

Dignard, N., Lalumière, R., Reed, A. and Julien, M. 1991. Habitats of the northeastern coast of James Bay. Occasional Paper No. 70. Environment Canada, Canadian Wildlife Service. Ottawa, ON. 27 p. + map.

Return to reference 78 referrer

Reference 79

Ettinger, K., Lajoie, G. and Beaulieu, R. 1995. Wemindji Cree knowledge of eelgrass distribution and ecology. Unpublished report prepared for the Cree Regional Authority and submitted to Fisheries and Oceans Canada. Quebec Region, QC. 50 p.

Return to reference 79 referrer

Reference 80

Abraham, K.F. and Jefferies, R.L. 1997. High goose populations: causes, impacts and implications. In Arctic ecosystems in peril: report of the Arctic Goose Habitat Working Group. Arctic Goose Joint Venture Special Publication. Edited by Batt, B.D.J. U.S. Fish and Wildlife Service and Canadian Wildlife Service. Washington, DC and Ottawa, ON. pp. 7-72.

Return to reference 80 referrer

Reference 81

Jefferies, R.L., Jano, A.P. and Abraham, K.F. 2006. A biotic agent promotes large-scale catastrophic change in the coastal marshes of Hudson Bay. Journal of Ecology 94:234-242.

Return to reference 81 referrer

Reference 82

Canadian Wildlife Service Waterfowl Committee. 2009. Population status of migratory game birds in Canada, 2009. CWS Migratory Birds Regulatory Report No. 28. Environment Canada. Gatineau, QC. 95 p.

Return to reference 82 referrer

Reference 83

Jefferies, R.L., Rockwell, R.F. and Abraham, K.F. 2003. The embarrassment of riches: agricultural food subsidies, high goose numbers, and loss of arctic wetlands - a continuing saga. Environmental Reviews 11:193-232.

Return to reference 83 referrer

Reference 84

Jefferies, R.L. and Rockwell, R.F. 2002. Foraging geese, vegetation loss and soil degradation in an arctic salt marsh. Applied Vegetation Science 5:7-16.

Return to reference 84 referrer

Reference 85

Handa, T. and Jefferies, R.L. 2000. Assisted revegetation trials in degraded salt-marshes. Journals of Applied Ecology 37:944-958.

Return to reference 85 referrer

Reference 86

McLaren, J.R. and Jefferies, R.L. 2004. Initiation and maintenance of vegetation mosaics in an arctic salt marsh. Journal of Ecology 92:648-660.

Return to reference 86 referrer

Reference 87

Ngai, J.T. and Jefferies, R.L. 2004. Nutrient limitation of plant growth and forage quality in Arctic coastal marshes. Journal of Ecology 92:1001-1010.

Return to reference 87 referrer

Reference 88

Bertness, M.D., Silliman, B.R. and Jefferies, R.L. 2004. Salt marshes under siege. American Scientist 92:54-61.

Return to reference 88 referrer

Reference 89

Rockwell, R.F., Witte, C.R., Jefferies, R.L. and Weatherhead, P.J. 2003. Response of nesting savannah sparrows to 25 years of habitat change in a snow goose colony. Ecoscience 10:33-37.

Return to reference 89 referrer

Reference 90

Rockwell, R.F., Abraham, K.F., Witte, C.R., Matulonis, P., Usai, M., Larsen, D., Cooke, F., Pollak, D. and Jefferies, R.L. 2009. The birds of Wapusk National Park. Wapusk National Park of Canada Occasional Paper No. 1. Parks Canada. Winnipeg, MB. 25 p.

Return to reference 90referrer

Reference 91

PARL. 2008. Standing committee on fisheries and oceans: evidence. Parliament of Canada, House of Commons. Number 016, 39th Parliament, 2nd Session. 13 p.

Return to reference 91 referrer

Reference 92

Hydro-Québec and GENIVAR Inc. 2001. La Grande complex environmental monitoring: the coastal habitats of James Bay. Summary report. 28 p.

Return to reference 92 referrer

Reference 93

Short, F.T. 2008. Report to the Cree Nation of Chisasibi on the status of eelgrass in James Bay: an assessment of Hydro-Québec data regarding eelgrass in James Bay, experimental studies on the effects of reduced salinity on eelgrass, and establishment of James Bay environmental monitoring by the Cree Nation. University of New Hampshire, Jackson Estuarine Laboratory. Durham, NH. 30 p. + appendices.

Return to reference 93 referrer

Reference 94

Tsuji, L.J.S., Gomez, N., Mitrovica, J.X. and Kendall, R. 2009. Post-glacial isostatic adjustment and global warming in subarctic Canada: implications for islands of the James Bay region. Arctic 62:458-467.

Return to reference 94 referrer

Reference 95

Gough, W.A. and Leung, A. 2002. Nature and fate of Hudson Bay permafrost. Regional Environmental Change 2:177-184.

Return to reference 95 referrer

Reference 96

Zhang, T., Barry, R.G., Knowles, K., Heginbottom, J.A. and Brown, J. 2008. Statistics and characteristics of permafrost and ground-ice distribution in the northern hemisphere. Polar Geography 31:47-68.

Return to reference 96 referrer

Reference 97

Smith, R.E., Veldhuis, H., Mills, G.F., Eilers, R.G., Fraser, W.R. and Lelyk, G.W. 1998. Hudson Plains Ecozone. In Terrestrial ecozones, ecoregions, and ecodistricts of Manitoba: an ecological stratification of Manitoba's natural landscapes. Agriculture and Agri-Food Canada, Research Branch, Brandon Research Centre, Land Resource Unit. Brandon, MB. pp. 277-300. (map at 1:1,500,000 scale).

Return to reference 97 referrer

Reference 98

Crins, W.J., Gray, P.A., Uhlig, W. and Webster, M. 2009. The ecosystems of Ontario, part 1: ecozones and ecoregions. Technical Report SIB TER IMA TR-01. Ontario Ministry of Natural Resources, Inventory, Monitoring and Assessment Section. Peterborough, ON. 71 p.

Return to reference 98 referrer

Reference 99

Riley, J.L. 2003. Flora of the Hudson Bay Lowland and its postglacial origins. NRC Press. Ottawa, ON. 236 p.

Return to reference 99 referrer

Reference 100

Ganter, B., Cooke, F. and Mineau, P. 1996. Long-term vegetation changes in a snow goose nesting habitat. Canadian Journal of Zoology 74:965-969.

Return to reference 100 referrer

Reference 101

Sammler, J.E., Andersen, D.E. and Skagen, S.K. 2008. Population trends of tundra-nesting birds at Cape Churchill, Manitoba, in relation to increasing goose populations. The Condor 110:325-334.

Return to reference 101 referrer

Reference 102

Iacobelli, A. and Jefferies, R.L. 1991. Inverse salinity gradients in coastal marshes and the death of stands of Salix : the effects of grubbing by geese. Journal of Ecology 79:61-73.

Return to reference 102 referrer

Reference 103

Abraham, K.F., Jefferies, R.L. and Rockwell, R.F. 2005. Goose-induced changes in vegetation and land cover between 1976 and 1997 in an Arctic coastal marsh. Arctic, Antarctic, and Alpine Research 37:269-275.

Return to reference 103 referrer

Reference 104

Abraham, K. (Ontario Ministry of Natural Resources). 2009. ATV damage to tundra in the Ontario portion of the Hudson Plains Ecozone+. Personal observation.

Return to reference 104 referrer

Reference 105

Scott, P.A., Hansell, R.I.C. and Fayle, D.C.F. 1987. Establishment of white spruce populations and responses to climatic change at the treeline, Churchill, Manitoba, Canada. Arctic and Alpine Research 19:45-51.

Return to reference 105 referrer

Reference 106

Harsch, M.A., Hulme, P.E., McGlone, M.S. and Duncan, R.P. 2009. Are treelines advancing? A global meta-analysis of treeline response to climate warming. Ecology Letters 12:1040-1049.

Return to reference 106 referrer

Reference 107

Return to reference 107 referrer

Reference 108

Parkinson, C.L. and Cavalieri, D.J. 2008. Arctic sea ice variability and trends, 1979-2006. Journal of Geophysical Research-Oceans 113, C07003, 28 p.

Return to reference 108 referrer

Reference 109

Gagnon, A.S. and Gough, W.A. 2005. Trends in the dates of ice freeze-up and breakup over Hudson Bay, Canada. Arctic 58:370-382.

Return to reference 109 referrer

Reference 110

Rouse, W.R. 1991. Impacts of Hudson Bay on the terrestrial climate of the Hudson Bay Lowlands. Arctic and Alpine Research 23:24-30.

Return to reference 110 referrer

Reference 111

COSEWIC. 2008. COSEWIC assessment and update status report on the polar bear Ursus maritimus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa, ON. vii + 75 p.

Return to reference 111 referrer

Reference 112

Hersteinsson, P. and Macdonald, D.W. 1992. Interspecific competition and the geographical distribution of red and arctic foxes Vulpes vulpes and Alopex lagopus . Oikos 64:505-515.

Return to reference 112 referrer

Reference 113

Stirling, I., Lunn, N.J. and Iacozza, J. 1999. Long-term trends in the population ecology of polar bears in western Hudson Bay in relation to climatic change. Arctic 52:294-306.

Return to reference 113 referrer

Reference 114

Stirling, I., Lunn, N.J., Iacozza, J., Elliott, C. and Obbard, M. 2004. Polar bear distribution and abundance on southwestern Hudson Bay coast during open water season, in relation to population trends and annual ice patterns. Arctic 57:15-26.

Return to reference 114 referrer

Reference 115

Gough, W.A., Cornwell, A.R. and Tsuji, L.J.S. 2004. Trends in seasonal sea ice duration in southwestern Hudson Bay. Arctic 57:299-305.

Return to reference 115 referrer

Reference 116

Heginbottom, J.A., Dubreuil, M.A. and Harker, P.A.C. 1995. Permafrost, 1995. In The national atlas of Canada. Edition 5. National Atlas Information Service, Geomatics Canada and Geological Survey of Canada. Ottawa, ON. Data to reproduce map obtained from Geogratis. © Department of Natural Resources Canada. All rights reserved.

Return to reference 116 referrer

Reference 117

Smith, S.L., Burgess, M.M., Riseborough, D. and Nixon, F.M. 2005. Recent trends from Canadian permafrost thermal monitoring network sites. Permafrost and Periglacial Processes 16:19-30.

Return to reference 117 referrer

Reference 118

Smith, S. 2011. Trends in permafrost conditions and ecology in Northern Canada. Canadian Biodiversity: Ecosystem Status and Trends 2010, Technical Thematic Report No. 9. Canadian Councils of Resource Ministers. Ottawa, ON. iii + 22 p. Technical Reports.

Return to reference 118 referrer

Reference 119

Kershaw, G.P. 2010. Climate change at the Arctic's edge: field report. Earthwatch Institute. Edmonton, AB. 12 p.

Return to reference 119 referrer

Reference 120

Sladen, W.E., Dyke, L.D. and Smith, S.L. 2009. Permafrost at York Factory national historic site of Canada, Manitoba, Canada. Current Research 2009-4. Natural Resources Canada, Geological Survey of Canada. Ottawa, ON. 10 p.

Return to reference 120 referrer

Reference 121

Stewart, H. (Parks Canada). 2009. Permafrost monitoring in Wapusk National Park, Manitoba. Personal communication.

Return to reference 121 referrer

Reference 122

Obbard, M. (Ontario Ministry of Natural Resources). 2009. Permafrost monitoring in the Ontario portion of the Hudson Plains Ecozone+. Personal communication.

Return to reference 122 referrer

Reference 123

Camill, P. 2005. Permafrost thaw accelerates in boreal peatlands during late- 20th century climate warming. Climatic Change 68:135-152.

Return to reference 123 referrer

Reference 124

Thibault, S. and Payette, S. 2009. Recent permafrost degradation in bogs of the James Bay area, Northern Quebec, Canada. Permafrost and Periglacial Processes 20:383-389.

Return to reference 124 referrer

Reference 125

Gagnon, A.S. and Gough, W.A. 2005. Climate change scenarios for the Hudson Bay region: an intermodel comparison. Climate Change 69:269-297.

Return to reference 125 referrer

Reference 126

Ho, E., Tsuji, L.J.S. and Gough, W.A. 2005. Trends in river-ice break-up data for the western James Bay region of Canada. Polar Geography 29:291-299.

Return to reference 126 referrer

Reference 127

Bonsal, B.R., Prowse, T.D., Duguay, C.R. and Lacroix, M.P. 2006. Impacts of large-scale teleconnections on freshwater-ice break/freeze-up dates over Canada. Journal of Hydrology 330:340-353.

Return to reference 127 referrer

Reference 128

Duguay, C.R., Prowse, T.D., Bonsal, B.R., Brown, D.G., Lacroix, M.P. and Ménard, P. 2006. Recent trends in Canadian lake ice cover. Hydrological Processes 20:781-801.

Return to reference 128 referrer

Reference 129

Latifovic, R. and Pouliot, D. 2007. Analysis of climate change impacts on lake ice phenology in Canada using the historical satellite data record. Remote Sensing of Environment 106:492-507.

Return to reference 129 referrer

Top of Page