Species of special interest

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Amphibians

Amphibians are an integral part of aquatic food webs, feeding on algae and insects at different life stages and serving as food for a wide range of predators, including dragonflies, fish, snakes, and birds. They are particularly sensitive to pollutants absorbed through their skin, which makes them good indicators of wetland contamination and degradation.1

In the Great Lakes Basin, four amphibian species, American toad, western chorus frog, northern leopard frog, and green frog, may have declined since the mid-1990s. Spring peeper is the only species out of eight monitored that has been increasing. However, the timeline is too short to be certain that these are long-term trends and not part of natural variation.1 In the St. Lawrence River, 27% of amphibians and reptiles are at risk within the highly developed river corridor.2 The northern leopard frog is considered Threatened in Alberta, red-listed in B.C., and assessed as Endangered (Rocky Mountain population), Special Concern (Western Boreal/Prairie populations) or Not At Risk (Manitoba and eastern populations) by COSEWIC.3

Batrachochytrium dendrobatids (Bd), a chytrid fungus of the skin, has been implicated in worldwide amphibian declines4 (see Invasive Non-native Species). Ranaviruses have also been responsible for mass die-offs of amphibians worldwide.5 Canada’s Boreal Shield,6 Prairies,7 and Mixedwood Plains6, 8 ecozones+ have documented cases of ranaviruses.

Amphibians in the Great Lakes Basin
Annual occurrence index (percent of monitoring stations where the species was recorded), 1995 to 2007
Graphs: amphibians in the Great Lakes basin. Click for graphic description (new window). iStock.com photos: Western chorus frog © rmarnold; Northern leopard frog © maimai; Bullfrog © Valmol48; Gray treefrog © HKPNC. dreamstime.com photos: American toad © David Anderson Wetlands, Algonquin Provincial Park; Ontario © Elena Elisseeva; Spring peeper © Jason Ross; Wood frog © Mircea Costina; Green frog © Electrochris.
Long Description for Amphibians in the Great Lakes Basin

This graphic contains 8 line graphs displaying the annual occurrence index (percent of monitoring stations where the species was recorded) for eight species of amphibians, from 1995 to 2007. There is a photo of each species on each graph and also a photo showing amphibian habitat – wetlands in Algonquin Provincial Park, Ontario. The overall trends varied, with some declines and some species without clear trends over the relatively short period of record.

The graphs are described in the following set of points:

  1. American toad: a significant decline (recorded at approximately 57% of stations in 1995 and at 40% of stations in 2007);
  2. western chorus frog: a significant decline (at 75% of stations in 1995 and at approximately 45% of stations in 2007);
  3. northern leopard frog: overall a significant decline, with increases through the mid 1990s from being recorded at approximately 35% of sites to approximately 65% of sites, then a decrease, with the index fluctuating around 35% after 2000;
  4. bullfrog: fluctuations, with slightly higher values in the first 4 years of record but no significant trend (with the species recorded at approximately 50% of sites in 1995 and approximately 45% of sites in 2007);
  5. gray treefrog: no significant trend; a sharp initial increase from fewer than 60% of sites in 1995 to just fewer than 80% in 1996, followed by fluctuating levels, with some indication of declines in the most recent years (index values for 2004 through 2007 being approximately 77%, 60%, 60% and 55%).
  6. spring peeper: no trend; present at the same percentage of monitoring stations in 1995 as in 2007 (approximately 70%), but showing large increases and declines in the years between, reaching an index value of approximately 95% in three years
  7. wood frog: no trend; found at a consistently lower number of stations than other amphibians recorded; fluctuating between approximately 22% and 40% over the 12 years. In 1995 wood frogs were recorded at approximately 30% of stations and in 2007 they were recorded at approximately 35% of stations; and
  8. green frog: overall significant decline; a sharp increase from approximately 70% of sites in 1995 to approximately 90% in the late 1990s, followed by a sharp decline to approximately 55% in 2000, followed by fluctuations since 2000 between 55% and 70%.
Source: Archer et al., 2009.1
Globe

Global Trends

As of 2004, 43% of amphibian populations were in decline and 33% of all amphibian species were globally threatened. The dominant causes of declines worldwide are habitat reduction (North America and Europe), over-exploitation (Asia), and unexplained causes, possibly linked to disease (South America, Australia, and New Zealand).9
 

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Fishes using freshwater habitat

Fishes occur in almost all aquatic habitats and represent the largest group of vertebrates in the world.1 Although freshwater is relatively scarce globally, covering only 1% of the Earth’s surface, about 43% of the 29,000 to 32,000 fish species live in freshwater for at least part of their lives.2, 3 With over 8,500 rivers and two million lakes, covering almost 9% of the total land area,4 Canada has a disproportionate amount of the global freshwater habitat, but only about 200 species of native freshwater and diadromous fish. (Diadromous fishes use both marine and freshwater.2)

Fishes are among the world’s most important natural resources, providing numerous goods and services, including an annual global harvest of 92 million tonnes; 10.1 million tonnes from inland waters, most of which is freshwater.5 The commercial freshwater harvest in Canada is over 32,000 tonnes and valued at almost $68 million.6

This section is further divided into the following four topics:

Globe

Global Trends

An estimated 37% of the world’s freshwater fishes are threatened with extinction.17
 

Native freshwater and diadromous fishes at risk

Number of Extirpated, Endangered, Threatened, or Special Concern species
Graph: freshwater and diadromous fishes at risk. Click for graphic description (new window).
Long Description for Native freshwater and diadromous fishes at risk

This bar graph shows the number of Extirpated, Endangered, Threatened, or Special Concern species of freshwater and diadromous fish in 1980, 1999, 2000, and 2010. In 1980 fewer than 5 species fell under these “at risk” categories; by 1999 the number had increased to 42 species, increasing again by 2000 to 60 species. By 2010, 80 species were classified as being at risk.

Note: Diadromous fish use both marine and freshwater. Trends reflect a combination of changes in the condition of species as well as the addition of new information.
Source: data compiled by Hutchings, 20108 from Hutchings and Festa- Bianchet, 20097 and COSEWIC, 20109

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has assessed 18% (35 species) of freshwater and diadromous fishes as Endangered or Threatened throughout all or parts of their ranges. Fifty-eight species (29%) have been assessed as at risk, which includes species assessed as Extirpated and of Special Concern, as well as those that are Endangered or Threatened.7-9 The number of fishes at risk has been growing since the 1980s. The leading causes of declines in Canadian freshwater fishes are habitat loss and habitat fragmentation – caused by dams, weirs, roads and degradation of the riparian zone – and non-native aquatic species.3, 10-12 Overfishing, pollution, climate change, and interactions between wild and farmed species are also linked to declining populations of freshwater fishes.2

Sturgeon, species at risk

Photo: juvenile sturgeon © Traci JensenAll 24 species of sturgeon in the world are at risk, although definitions of “at risk” vary. Two of the five species in Canada are classified as Endangered or Threatened.13 White sturgeon, the largest freshwater fish in Canada, is restricted to the west coast of North America.14 Its size (up to 6 metres), longevity (over 100 years), and late maturity (14 to 30 years), make it especially vulnerable to overexploitation and habitat degradation.15 Of the six B.C. white sturgeon populations, three are declining (Columbia, Kootenay, Nechako), one is now more stable, with some fluctuations (lower Fraser), and two are stable (mid and upper Fraser). Poor juvenile survival, linked to river diversions, changes in sediment quantity and quality, and water flow regulation, associated with dams, are the primary reasons for endangerment of the three declining populations.15, 16

White sturgeon, Nechako River populations
Juvenile production, 1945 to 1990
Graph: juvenile white sturgeon production, Nechako River populations. Click for graphic description (new window).
Long Description for White sturgeon, Nechako River populations

This line graph plots an index of juvenile production for white sturgeon in the Nechako River from 1945 to 1990. The building of the Kenney Dam in 1952 and the following 5 year period during which the reservoir filled are marked on the graph, as are the dates of two slides into the upper Nechako River near Cheslatta Falls in 1961 and 1972. 1950 marked the beginning of a sharp increase in juvenile production, increasing from an index value of 50 in 1949 to 250 in 1953. From 1953 to 1963, annual juvenile production fluctuated widely and then began a rapid decline from 1964 to 1967. From 1967 to 1990 the index of juvenile production remained close to 0 with little variation.

Source: McAdam et al., 200516

Lake sturgeon once sustained large commercial fisheries. Reductions of 50 to 98% have been observed in western Canadian rivers and lake sturgeon have disappeared from the Red-Assiniboine River and Lake Winnipeg. Great Lakes populations have been reduced to a fraction of their original size, and populations in the Ottawa and St. Lawrence rivers are showing recent declines. Before the turn of the century, overfishing was the main threat to lake sturgeon. In recent years, declines are attributed to habitat fragmentation and degradation in the Great Lakes, as well as overfishing, dams, contaminants, and invasive species elsewhere.13

American eel

American eel in Ontario
Average number (thousands) of eels per day at R.H. Saunders Hydroelectric Dam, 1974 to 2005
Graph: American eel in Ontario. Click for graphic description (new window).
Long Description for American eel in Ontario

This line graph shows the average number of eels per day counted at a fish ladder at the R.H. Saunders Hydroelectric Dam, near Cornwall, Ontario, from 1974 to 2005. The number of eels fluctuates annually but increased from fewer than 10,000 in 1974 to over 25,000 in 1982, and then declined sharply to 1986 when declines continued but at a slower rate. Between 1995 and 2005, the number of eels remained at very low levels, well under 500 per day.

Note: no data are available for 1996.
Source: Ontario Ministry of Natural Resources, 201034

The American eel is an example of a once abundant species that is now listed as Special Concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Since the 1970s, populations have declined by 99% in the upper St. Lawrence34 and less extreme declines have been observed in both the lower St. Lawrence and Gulf of St. Lawrence.35, 36 The long life span of American eels, combined with their vast migration distances of up to 4,500 km, make them vulnerable to a wide range of stressors, such as mortality in hydroelectric turbines, physical barriers such as dams, overharvesting, and habitat alteration. Climate change, resulting in changes to ocean currents that carry eel larvae from the spawning grounds, may also contribute to population declines. American eels once provided both subsistence and commercial fisheries in Canada.36

 

Prey fishes in the Great Lakes

Trends in prey fish biomass based on annual bottom trawl surveys
Map and graphs: population trends of prey fishes in the Great Lakes. Click for graphic description (new window).
Long Description for Prey fishes in the Great Lakes

This graphic consists of five line graphs and an associated map of the Great Lakes. The graphs display the trends in prey fish biomass in each Great Lake, based on annual bottom trawl surveys. Four of the five graphs show large biomass declines, especially in recent years. Time frames and measurement units vary from graph to graph.

Each graph is described in the following set of points, by location:

  1. Lake Superior, 1978 to 2007. The mean biomass of prey fish showed an overall pattern of increasing and then declining. In the early 1980s the mean biomass dipped to approximately 2 kilograms per hectare and then increased to fluctuate over a range of about 12 to 20 kilograms per hectare from 1986 to 1994. Values then decreased, fluctuating over a range of about 4 to 8 kilograms per hectare from 1996 to 2007.
  2. Lake Huron, 1992 to 2007. Biomass declined steadily from a peak of 300 kilotonnes in 1994 to approximately 40 kilotonnes in 2007.
  3. Lake Ontario, 1978 to 2007. Biomass of prey fish increased in the first years, with values of about 20 kilograms per trawl tow in 1974 and over 120 kilograms per trawl tow in 1981. From that point, biomass declined steeply, reaching approximately 10 kilograms per trawl tow in 2006 and 2007.
  4. Lake Michigan, 1973 to 2007. The trend was one of overall increase followed by decline. Values in the first 5 years of sampling were in the range of 100 to 120 kilotonnes. A steady increase, starting in1978, reached a peak in 1983 of approximately 450 kilotonnes. Biomass then declined steadily to low values of around 40 kilotonnes by 2007.
  5. Lake Erie, 1987 to 2007. Prey fish biomass showed no clear overall trend or pattern. In 1987 biomass was approximately 50 kilotonnes and in 2007 biomass was approximately 70 kilotonnes. In the years between, values fluctuated between a high of more than 80 kilotonnes and a low of approximately 20 kilotonnes.
Source: adapted from Environment Canada and U.S. Environmental Protection Agency, 200937

The term prey fish refers to fish species that are the main food items of popular commercial and sport fish. A fish is considered a prey fish if it remains small in size, usually feeds on zooplankton or bottom-dwelling species, and is abundant enough to feed a predator fish population.38 Prey fish make up the majority of fish biomass and are the foundation of the Great Lakes fishery (see commercial fishing), as they are eaten by predatory fish such as trout, walleye, and bass. Prey fish include native species such as slimy sculpin, trout-perch, cisco, and bloater, and also non-native species such as alewife, rainbow smelt, and round goby. Declines in prey fish populations have been occurring since the 1980s and 1990s. The most likely causes are: stocking of Pacific salmon, which was done to reduce non-native prey fish; reductions in nutrients; and non-native zebra and quagga mussels, which filter nutrients from the water column and reduce food for the invertebrates that prey fish eat.37

 

Sockeye salmon © iStock.com/RKoopmans
Sockeye salmon

Salmon

Canadian lakes and rivers provide spawning habitat for five species of wild salmon on the West Coast18 and one on the East Coast. Wild salmon are a staple and a cultural foundation species for Aboriginal Peoples.19, 20 They are the basis of commercial, recreational, and Aboriginal food, social, and ceremonial fisheries on both coasts.20, 21 Wild salmon are revered by Canadians, in part because of the mystique of their life cycle – after growing in the ocean they migrate long distances to spawn in freshwater.

Fraser River sockeye returns

Number of returning salmon (millions), 1952 to 2009
Four graphs: Fraser River sockeye returns for four cohorts. Click for graphic description (new window).
Long Description for Fraser River sockeye returns

This graphic consists of four bar charts showing the numbers of returning salmon from 1952 to 2009. Each chart represents a cohort of hatched fish and is described in the following set of points:

  1. 1952 to 2008 cohort. Returns were low relative to other cohorts throughout the 58-year period, reaching just over 5 million in 1984 and 1992.
  2. 1953 to 2009 cohort. Returns fluctuated around 5 million until 1976 when the returns begin to increase, reaching approximately 24 million in 1992.
  3. 1954 to 2006 cohort. Relatively high numbers of returns, approximately 12 million in 1952 and approximately 17 million in 1954, decreasing to approximately 3 million in 1960. This cohort’s returns began to increase to approximately 22 million in 1988 from which point the numbers declined again to approximately 13 million in 2004.
  4. 1955 to 2007 cohort. Did not reach the highs of the 1953 to 2009 cohort or the 1954 to 2006 cohort, but the returns were generally higher than the 1952 to 2008 cohort. In 1988 returns reached a peak of approximately 13 million, but otherwise remained below 7 million, with a low of approximately 1 million in 2004.
Note: it takes four years for most sockeye to return to spawn after hatching.
Source: adapted from Lapointe, 201022
Fraser River sockeye survival
Productivity index (returns/spawner)
4-year running average, 1952 to 2008
Graph: Fraser River sockeye survival. Click for graphic description (new window).
Long Description for Fraser River sockeye survival

This line graph displays annual sockeye survival as a productivity index measured as the number of returns per spawner. The graph plots the four-year running average from 1952 to 2008. Returns fluctuated over this period, reaching highs of approximately 7 million in 1960 and 1987 with a dip to over just over million in the mid 1960s. After 1992 returns showed a strong decreasing trend, with little fluctuation, reaching a low of approximately 1.5 million in 2007 and 2008.

Source: Fisheries and Oceans Canada (DFO), 201023

 

The Fraser River is legendary for its sockeye salmon runs. Since the 1990s, the number of returning sockeye has fluctuated widely, depending on the cohort (see graphs for the four cohorts above), while the survival rate – the proportion of fish that grow to adults and return to spawn – has been declining. In 2009, only 1.5 million adult sockeye returned – the lowest number since 1947. A scientific panel investigating the evidence for declining adult returns concluded that the major cause has been unfavourable physical and biological conditions in the Strait of Georgia, combined with freshwater and marine pathogens.23, 24 In 2010, mid-summer estimates predicted the largest Fraser River sockeye run since 1913.25

In some years, warming water and reduced flows due to climate change have impacted salmon migration, spawning, and rearing success. Sockeye survival and spawning are impaired as river temperatures increase above stock-specific thresholds.26, 27 Since the 1950s, mean summer temperatures in the Fraser River have increased by approximately 1.5°C.26, 28 This trend is likely to continue, increasing the probability of sockeye being exposed to water temperatures that will impair their survival.29

Atlantic salmon population trends

Hundreds of fish, 1970 to 2005
Map and graphs: Atlantic salmon population trends. Click for graphic description (new window).
Long Description for Atlantic salmon population trends

This graphic contains four plot graphs showing the number of Atlantic salmon returning to four rivers in the Atlantic Maritime from 1970 to 2005. Overall, all rivers show a decreasing trends since about 1990 with very low  returns in recent years. Data are plotted as annual points, with no trend lines. The accompanying map shows the watershed each river is a part of.

Each graph is described in the following set of points, by location:

  1. North River, part of the East Cape Breton watershed. Fewer than 1,000 fish returned annually until 1985 when the number of returns was between 1,000 and over 2,000. After the early 1990s numbers declined, reaching a low of approximately 100, and rising again to close to 500 in 2005.
  2. LaHave River, in the Southern Uplands watershed. Returning fish numbers increased from approximately 100 in the early 1970s to almost 8,000 in the late 1980s and then declined to consistent values of approximately 1,000 annually in the 1990s and 2000s.
  3. Stewiacke River, in the Inner Bay of Fundy watershed. Annual returns were distributed widely from 3,000 to 50. Following 1990 the numbers were consistently very low.
  4. St. John River, in the Outer Bay of Fundy watershed. The number of returning salmon ranged from 5,000 to 20,000 until approximately 1994, after which returns consistently remained at fewer than 5,000.
Source: adapted from Gibson et al., 200630

Returns of Atlantic salmon to many rivers in North America have declined since the 1980s or 1990s, with northern populations increasing and southern populations remaining at low levels.30 For example, in inner Bay of Fundy rivers, runs of 30 to 40 thousand fish in the mid-1980s have been reduced to a few hundred fish, and in southern Nova Scotia, most salmon exist only as remnant populations or have been extirpated.31, 32 Although the factors contributing to low marine survival are largely unknown, freshwater declines are a result of the effects of dams, loss of spawning habitat, invasive species, increases in stream temperatures, siltation, contaminants,33 poaching20 and, in southern Nova Scotia, acid deposition.20, 32

 

Photo: recreational fishers, interior British Columbia lake © iStock.com/MarvinBeatty
Interior British Columbia lake

Commercial freshwater fishing

Commercial fish production in Lake Winnipeg
Tonnes (thousands), 1883 to 2006
Graph: commercial fish production in Lake Winnipeg. Click for graphic description (new window).
Long Description for Commercial fish production in Lake Winnipeg

This line graph shows production for three species of commercial fish (walleye, whitefish, and sauger) in Lake Winnipeg, as well as the total fish production, from 1883 to 2006.

The four lines on the graph show the following:

  1. The total amount of fish harvested was highly variable, but generally increased from the late 19th century to a peak around 1940, then declined until about 1970 to a low of less than 500 tonnes. This was followed by an increase over the 1970s and by a period of fairly stable values in the range of 4,000 to 6,000 tonnes through the 1990s and to 2006.
  2. Walleye production was variable, mainly fluctuating at levels below 1,000 tonnes until the late 1990s, when the fishery increased, reaching a production of approximately 4,500 tonnes in 2006.
  3. Whitefish production was also highly variable and shows no overall trend. Production was generally within the range of a few hundred to below 2,000 tonnes, with peaks of approximately 3,500 in 1905 and 1936. In 2006 production was approximately 1,500 tonnes.
  4. Sauger production, which started in the late 1920s, increased rapidly to approximately 4,500 tonnes in 1941. The production declined from the peak and remained fairly stable at around 1,000 to 2,000 tonnes from the 1950s through the 1980s. Production declined steadily from 1990 to 2006 when production was approximately 500.
Source: adapted from Manitoba Water Stewardship Fisheries Branch as cited in Shipley and Kling, 201039

Lakes and rivers in Canada support significant commercial fisheries. Lake Winnipeg supports the largest commercial fishery in Manitoba, valued at approximately $20 million per year. Commercial fish production has been highly variable in Lake Winnipeg over the past 125 years, both in the amount of fish and the species harvested. For example, a dramatic decline in fish production from 1940 to the1960s was followed by an increase since the 1970s. Walleye production is now at historical highs and is the most important fishery species. Sauger, on the other hand, have been declining since the 1970s. Walleye are benefitting from the invasion of rainbow smelt and nutrient enrichment. These same factors are believed to be driving the decline in sauger.39, 40

The Great Lakes commercial fishery has an annual dockside value, in Ontario, that fluctuated between $29 and $37.5 million between 2004 and 2008,41 contributing $850 million per year in direct and indirect benefits to the Ontario economy. The overall commercial harvest has been declining since the 1980s. The main species harvested today are walleye and yellow perch, both native species, and rainbow smelt, a non-native species.42 Overfishing and predation by the non-native sea lamprey led to the collapse of lake trout in the late 1950s. Restoration, including stocking, has maintained a fishery, and lake trout are now reproducing in Lake Superior and Lake Huron.37, 43

Recreational freshwater fishing

Number of fish (millions), 1995 to 2005
Graph: recreational freshwater fishing. Click for graphic description (new window). Photo: Recreational fisher © Rob Stenner.
Long Description for Recreational freshwater fishing

This bar graph shows the number of fish caught and the number of fish retained in the recreational freshwater fishery in 1995, 2000, and 2005, indicating declines in both measures over the ten-year period. In 1995 approximately 250 million fish were caught and approximately 110 million were retained. In 2000 approximately 230 million fish were caught and approximately 80 million fish were retained. In 2005 approximately 220 million fish were caught, and approximately 60 million were retained.

Source: adapted from Orok and Johnson, 200544

Approximately 3.2 million people participated in freshwater recreational fishing, or angling, in 2005, down from 4.2 million in 1995. The reduction in number of anglers has resulted in a reduction in the number of fish caught and the number of fish retained. It has also had an economic impact. Direct expenditures on angling were about $2.5 billion in 1995, 2000, and 2005. Although the dollar value of expenditures has not changed, this represents a 19% decrease in expenditures over 10 years, when adjusted for inflation. Anglers concentrate on some of the same species as the commercial fishery, namely walleye and yellow perch, although other species, such as brook trout, rainbow trout, bass, and northern pike, are also important. In 2000, the Year of the Volunteer, Canadian anglers dedicated over a million days to habitat clean-up and other activities related to improving recreational fishing.44, 45

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Birds

Birds are widespread, readily observed, feed at many levels of the food web, and are responsive to environmental change, making them good indicators of ecosystem health. Birds play an important ecological role, providing food for other species, dispersing seeds, controlling insects, pollinating plants, and modifying habitat. Many also have economic and cultural significance – providing humans with food, recreation, enjoyment, and study and playing an important role in many cultures.

Over the past 20 years, the status of the world’s birds has deteriorated, with more species moving closer to extinction.1 Of particular concern are declines in formerly common species.1 In the last 40 years, 20 common North American bird species lost over 50% of their populations.1, 2 Birds are also shifting their ranges northward in response to climate change – nearly 60% of the 305 species found in North America in winter moved northward by an average of 1.4 km per year (56 km over the last 40 years)3 and breeding ranges of southern North American species have shifted north by an average of 2.4 km per year.4

Canada provides crucial breeding, migrating, and wintering habitat for a significant percentage of the world populations of many species. Nevertheless, the status and trends of birds in Canada are only partially understood. Good data exist for many species, particularly in southern Canada; however, only localized data exist for many others, particularly in the North.

This section is further divided into the following four topics:

Globe

Global Trends

Globally, over 150 species of birds have been lost since the 16th century and one in eight is currently threatened with extinction. The last 20 years have witnessed a steady decline of bird species in terrestrial, freshwater, and marine ecosystems. Between 1988 and 2008, the status of 225 bird species was elevated to a higher level of risk.1
 

Photo: western sandpipers © Jason Puddifoot
Western sandpipers

Shorebirds

Sixty percent of North American shorebirds breed in the Arctic, with the Canadian Arctic providing 75% of the breeding range for 15 of 49 common species.5 Canada has migration sites of great importance as well, including at least three of hemispheric significance – the Bay of Fundy, the Fraser River estuary, and Chaplin/Old Wives/Reed Lakes in Saskatchewan.6 Some southern breeding areas, for example the Prairies, are of global importance to some species.7

Data on shorebird populations are patchy in Canada, but most information indicates declining trends.7-9 Of the 35 species examined in 2000, 49% showed significant declines somewhere in their range.5 The most complete datasets in Canada include the Breeding Bird Survey and the Atlantic Canada Shorebird Survey. Results from these surveys indicate:

  • Between 1976 and 2007, 4 of 12 species (33%) of shorebirds breeding in southern Canada declined significantly. There were no significant increases.10
  • Between 1974 and 2006, 5 of 15 migrating shorebird species (33%) on the Atlantic coast showed significant declines.11, 12

Potential causes of declines of shorebirds include loss and degradation of habitat, climate change, changes in predator regimes (for example, increasing numbers of peregrine falcons may cause shorebirds to move through an area more quickly, leading to an apparent decline13), human disturbance, contaminants, and disease.5 Changes are expected to accelerate due to anticipated changes in Arctic breeding habitat,14 as well as flooding and droughts elsewhere in shorebird ranges7 as a result of climate change.

 

Photo: northern gannets © John Chardine
Populations of northern gannets like this one on Bonaventure Island, Quebec, have increased in North America since the 1950s

Trends in status of breeding seabird populations in Canada

Number of populations in each category, 1980s to 2000s
Graph: trends in status of breeding seabird populations. Click for graphic description (new window).
Long Description for Trends in status of breeding seabird populations in Canada

This bar graph shows the number of breeding seabird populations in Canada that were increasing, stable, and decreasing in the 1980s, 1990s, and 2000s. It shows three bars for each decade. Overall there was a decline in the number of increasing populations and an increase in the number of decreasing populations. In the 1980s, 10 populations were increasing, 3 were stable, and 10 were decreasing. In the 1990s, 8 populations were increasing, 2 were stable, and 14 were decreasing. In the 2000s, 6 populations were increasing, 3 were stable, and 14 were decreasing.

Note: only populations with significant breeding populations, long-term datasets, and those unaffected by terrestrial human activities are included.
Source: adapted from Gaston et al., 200915

 

 

 

Worldwide, the status of seabirds is deteriorating faster than any other bird group.1 In Canada, trends are regional in nature and result from a variety of factors, including climate change, fishing by-catch, resource extraction, transportation, and pollution.15-20 A trend to an earlier breeding date has been found in several populations,21-23 as have changes in diet and condition.24

 
  • Pacific – southern populations, influenced by the changes in sea surface temperature related to the upwellings of the California Current, have been declining since the 1970s.15 Declines may also be due in part to a mismatch in timing between breeding and peak of food availability.25 Populations north of the influence of the current, however, have generally increased since the 1980s.15
  • Atlantic – prior to 1990, populations generally showed positive trends. A major cold-water event in 1990, however, coinciding with overfishing, disrupted food webs,26-29 resulting in immediate change in diet, condition, and population, particularly for gulls.24 Populations of most diving seabirds increased over this period, in part due to closure of the gillnet fishery that had been drowning many birds.30
  • Arctic – with the exception of ivory gulls, which are declining rapidly, change in Arctic seabird populations is slow and possibly the result of events on wintering grounds in the Northwest Atlantic.31, 32 Changes in seabird diet and growth have been found to be related to reduction of Hudson Bay sea ice. This may have negative consequences for populations in the long term.32 Conversely, in the High Arctic, less sea ice may benefit the birds.33, 34
Photo: ivory gulls © Mark Mallory


Ivory gulls

 

Photo: ducks © iStock.com/4loops

Waterfowl

Waterfowl have been monitored cooperatively by Canada and the U.S. since 1948. Concern over declines in populations in the 1980s led to the development of a large international cooperative initiative, the North American Waterfowl Management Plan, to address the declines. Although many duck populations fluctuate widely among years and regions, overall trends for most inland breeding ducks show increases or no significant change between 1961 and 2009.43, 44 Nevertheless, the populations of some species remain low; for example, northern pintail, American wigeon, and greater and lesser scaup have declined significantly in the prairie and western boreal regions.43, 44

Population trends for ring-necked ducks and scaup, western boreal region

Millions, 1961 to 2009
Two graphs showing population trends of ring-necked duck and scaup in the western boreal region. Click for graphic description (new window).
Long Description for Population trends for ring-necked ducks and scaup, western boreal region

This graphic contains two line graphs showing population trends for ring-necked ducks and scaup from 1961 to 2009. An inset map of Canada shows the location of the western boreal region, which is the survey area. Despite annual fluctuations in both species, the population of ring-necked duck increased significantly from approximately 200,000 in 1961, to approximately 1.1 million in 2009, while scaup declined significantly over the same time period. With a population fluctuating around 3.5 million between 1961 and 1970, scaup increased in 1971 to over 6 million, and then showed a steady decline to a low of 3.7 million in 2008.

Source: Canadian Wildlife Service Waterfowl Committee, 200943
Locator map of the western boreal region. Click for graphic description (new window).
Long description for Population trends for ring-necked ducks and scaup, western boreal region

This graphic contains two line graphs showing population trends for ring-necked ducks and scaup from 1961 to 2009. An inset map of Canada shows the location of the western boreal region, which is the survey area. Despite annual fluctuations in both species, the population of ring-necked duck increased significantly from approximately 200,000 in 1961, to approximately 1.1 million in 2009, while scaup declined significantly over the same time period. With a population fluctuating around 3.5 million between 1961 and 1970, scaup increased in 1971 to over 6 million, and then showed a steady decline to a low of 3.7 million in 2008.

Approximately 70% of scaup and ringnecked ducks breed in the western boreal forest and the two species share many life history traits.45 Nevertheless, scaup declined at an average of 1.7% per year between 1961 and 2009 while ring-necked ducks increased by 2.5% per year.43 Reasons for the decline in scaup remain unclear but hypotheses include: contamination or change in food resources; and reduced female survival or reproductive success due to changes in the boreal forest.46, 47 Another possible cause is a mismatch between timing of nesting and food availability due to temperature change for late- nesting species such as scaup.45 Population declines have also been found in other late-nesting species such as scoters.43, 45 Ring-necked ducks breed earlier.

American black duck

Over 90% of the world population of American black ducks breed in eastern Canada48 and the population declined by almost 50% between 1955 and 1985.49 One of the most abundant ducks in eastern Canada, the population has been stable at about 450,000 since 1990, although declines continue in the Mixedwood Plains.43, 44 Causes for the decline are not clear but likely include habitat loss due to development and agriculture49, 50 and displacement through competition with mallards,51 which have been expanding in abundance and range.49, 50, 52 Population increases in other areas could be due to changes in management practices, such as increased hunting restrictions.53

Sea ducks

Photo: king eider © iStock.com/eyebexData for sea ducks are limited because most breed in remote, inaccessible areas in the North.43 Existing data show a mix of trends. Reasons for declines are largely unknown,43 but declines in eiders may be related to harvest and avian cholera may be an issue.54

Upward green arrow mergansers in prairie, boreal, and Atlantic regions
Upward green arrow common goldeneye in prairie and Atlantic regions
Upward green arrow bufflehead in prairie and boreal regions
Downward red arrow scoters in prairie and boreal
Upward green arrow surf scoters in Atlantic43 regions
Downward red arrow long-tailed duck in boreal regions
Downward red arrow Arctic breeding populations of eiders54-58

 

 

 

Landbird populations in Canada

Percent change by habitat type, 1970s to 2000s
Graph: percent change in landbird populations by habitat type in Canada. Click for graphic description (new window).
Long Description for Landbird populations in Canada

This bar graph shows the percent change of Canadian landbird populations in five habitat types from the 1970s to the 2000s. Overall, populations of landbirds in all habitats experienced significant declines except forest birds which showed a non-significant decline of 10% overall. Grassland birds suffered the greatest overall declines at 44%. Birds of other open habitats declined by 42%, urban birds by 22%, and shrub birds by 17%.

Note: data for the 2000s decade includes only 2000 to 2006.
Source: Downes et al., 2010,35 adapted from Breeding Bird Survey data, 200736

 

 

 

Populations of landbirds in all habitat types except forest declined significantly from 1968 to 2006.35 No significant positive trends in any landbird groupings (by habitat, by foraging, or by migration strategy) were evident between 1968 and 2006, although significant positive trends were found for some individual species.35

 
  • Grassland birds, with more than 40% loss of total population since the 1970s, show significant steep declines in all regions of the country and for most species. This is consistent with declines throughout North America10, 37 and is thought to be due to a combination of habitat loss and the intensification of agriculture.35
  • Birds of other open habitats have been declining since the late 1980s. The assemblage contains several species of aerial-foraging insectivores, many of which are showing declines.35
  • The urban group is heavily influenced by two introduced species, European starling and house sparrow, which, although still abundant, are showing declines in Canada and Europe.35
  • The decline in shrub/early succession birds is strongly influenced by declines in relatively abundant sparrows.35 Significant declines were found in the Atlantic Maritime, Boreal Plains, and Boreal Shield ecozones+.
  • Similar to the U.S.,37forest birds show little change overall, although data indicate a decline since the 1990s.35 Trends for individual species vary, with some showing declines while others are stable or increasing. There have been varying degrees of decline in the Pacific Maritime, Montane Cordillera, and Western Interior Basin ecozones+, and increases in the Prairie and Mixedwood Plains where birds have responded to increased forest cover. About 60% of Canada’s landbirds breed in the boreal forest.38
  • Aerial and ground-foraging birds show significant declines of 35 and 27% respectively since the 1970s.35Aerial-foraging insectivores, such as swallows and flycatchers, stand out as a group showing large declines.39, 40 Causes remain unknown but likely include changes in food, climate, and habitat.
  • Long-distance and short-distance migrants showed significant declines of 21 and 24% respectively, while resident birds were unchanged.35 Short-distance migrants include many grassland species. Long-distance migrants include many aerial-foraging insectivores. Loss and fragmentation of habitat on the wintering grounds is one possible cause for decline.41, 42

 

Photo: eastern meadowlark © iStock.com/Canon_BobEastern meadowlark,
grassland bird, declined by 77%

Photo: American kestrel © iStock.com/pollyconn
American kestrel,
bird of other open habitat, declined by 45%

Photo: house finch © iStock.com/MichaelStubblefieldHouse finch,
urban bird, increased by over 200%

 

Photo: mourning warbler © iStock.com/PaulTessierMourning warbler,
shrub bird, declined by 48%

Photo: downy woodpecker © iStock.com/brm1949Downy woodpecker,
forest bird, increased by 30%

 

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Photo: caribou © Anne Gunn

Caribou

Caribou are distributed across most of Canada and can play important ecological roles as herbivores influencing the structure of plant communities, as prey supporting populations of large and medium-sized predators and scavengers, and as a source of nutrients in otherwise nutrient-limited systems. Caribou are an integral part of many cultures, particularly Aboriginal cultures, which have developed with caribou over thousands of years.1

This section is further divided into the following two topics:

Globe

Global Trends

Caribou and reindeer have a circumpolar distribution in the world’s tundra and boreal zones. Wild populations have declined in Russia and are mostly extirpated from Europe, except for a small, stable reindeer population in Norway, and an increasing population in Finland.28 Loss of habitat and climate change are threats worldwide.29
 

Caribou of the Arctic and taiga

Caribou of the Arctic and taiga population trends
Based on information available in August 2010
Map: Caribou of the Arctic and Taiga population trends. Click for graphic description (new window).
Long Description for Caribou of the Arctic and taiga population trends

This map of Canada and Alaska displays the ranges of North American northern caribou herds and their population trends based on information available in August 2010. Question marks on the map indicate some herds as being "under study", meaning that there was a recent census in progress or not yet fully analyzed at the cut-off date for results for this report. Herds for which the trend was based on preliminary data are indicated with an asterisk. Herds are listed here roughly from west to east: In Alaska, the Western Arctic herd is stable; the Teshekpuk Lake herd is increasing; the Central Arctic herd is increasing; and the Porcupine herd (with a range straddling northeast Alaska and the Canadian northwest) is declining. The Cape Bathurst herd is stable, the Bluenose West herd is stable the Bluenose East herd is increasing, the Bathurst herd is declining, the Ahiak herd’s status is unknown, the Beverly herd is declining and under study, the Qamanirjuaq herd is declining, and the Southampton herd is declining. Peary caribou, inhabiting the High Arctic islands, are decreasing. The Dolphin and Union herd is decreasing; the Lorillard herd's trend is unknown and under study; the Wager Bay herd is decreasing and marked as under study. Northern Baffin Island caribou are declining, based on preliminary data, and southern Baffin Island caribou are declining and are currently under study. Along the south of Hudson Bay, the Cape Churchill herd is stable and the Pen Island herd is decreasing; the status of the Coats Island herd is unknown and under study. On the Ungava Peninsula, the Leaf River herd is increasing and under study and the George River herd is declining and under study.

Source: adapted from Gunn and Russell, 2010,2 CARMA, 2009,10 Magoun et al., 2005,15 Elliot, 199816

Abundance of northern caribou, like other northern herbivores, such as lemmings and hares, is cyclic. Caribou numbers generally increased from lows in the mid-1970s to peaks in the mid-1990s, returning to lows by 2009 that are, in some cases, similar to previous lows.2 Some herds, notably the Bathurst and Beverly, which calve in the central Arctic, have experienced severe drops in the past few years.3, 4 Current declining trends may be partly related to natural cycles in abundance.2

Abundance of Peary caribou, which live on the High Arctic islands and are listed as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC),5 is largely influenced by weather. Periodic severe winters trigger large-scale mortality and reduction in productivity.5 Populations have declined by as much as 98% on several islands.6, 7 During two winters in the 1990s, more than 95% of the Peary caribou population in the western half of its range was devastated by heavy snow and the formation of ice layers in the snow.6 Events like these are projected to become more frequent and more widely distributed with climate change.6, 8, 9

Significant changes on caribou ranges since the 1970s could prevent a recovery of some herds to previous peak numbers.10 These changes include the effects of climate change, including changes in wildfire,11 and an increasing presence of people and development, particularly mining and oil and gas activity.12-14 Caribou harvest by humans and predation are also known to affect abundance within some caribou herds.5

 

Forest-dwelling woodland caribou

Map and graphs: status and range of forest-dwelling woodland caribou populations. Click for graphic description (new window).
Long Description for Forest-dwelling woodland caribou population status

This graphic contains a map of Canada showing the range of five populations of forest-dwelling woodland caribou and the status and trends of each population. The map also shows the historical southern boundary of caribou ranges. Current ranges have retracted north of this boundary. In western Canada the historical range excluded the Pacific Maritime and extended south including a portion of the U.S. Rockies. Moving east, the southern boundary followed the boundary of the Prairie Ecozone+ and then dipped into the U.S. side of Lake Superior and cut across southern Ontario just north of the Boreal Shield/Mixedwood Plains border before dipping back into the U.S. near the Ontario and Quebec border.

Associated with each population shown on the map is a bar graph displaying the population trends for each population as well as its COSEWIC status.

Information on status and trends of each population is displayed either as a graph or in note form, as described in the following set of points:

  1. The Northern mountain population had 4 herds increasing, 7 stable, 2 decreasing, and 23 unknown in 2010 (reference 19). Its COSEWIC status is Special Concern. Its current range includes much of the Boreal Cordillera and southern the Taiga Cordillera.
  2. The boreal population had 3 herds increasing, 16 stable, 17 decreasing and 21 herds unknown in 2008 (reference 17). Its COSEWIC status is Threatened. The current range of this population extends broadly through the boreal and taiga forested regions of Canada covering most of the Taiga Plains, the eastern portion of the Boreal Plains, the northern portion of the Boreal Shield, southern portion of the Taiga Shield in Quebec, and the southern part of the Hudson Plains.
  3. The southern mountain population had 13 of 19 herds decreasing in 2002 (reference 18). Its COSEWIC status is Threatened. The population’s current range is in three main areas within the Montane Cordillera Ecozone+, with a few small remnant patches in the southern Montane Cordillera. As of 2002, the range in B.C. had decreased by up to 40% (reference 18).
  4. The Atlantic-Gaspésie population had fewer than 200 adults in 2002 and the current population is isolated in a fraction of its original range (reference 18). The range of this population is shown as a line pointing to the Gaspé region of Quebec.
  5. The Insular Newfoundland population had 1 of 27 herds declining in 2002 (reference 18). The range of this population is shown as a line pointing to the island of Newfoundland.
Source: range for boreal population and southern boundary of historical extent adapted from Environment Canada, 2008,17 range for southern and northern mountain populations adapted from Thomas and Gray, 200218

Forest-dwelling woodland caribou are relatively non-migratory and live in smaller groups than their northern counterparts. They divide their time between lichen-rich mature forest and open areas, including alpine tundra.18 Historically occurring over much of Canada, their distribution has retracted, with the southern boundary continuing to move northward.18, 20 Caribou had completely disappeared from Nova Scotia and New Brunswick by 1930.21

The status of many herds remains unknown; however, where data exist, declines are evident, particularly for the boreal17 and southern mountain populations.22 Woodland caribou are declining primarily because of loss and degradation of habitat and landscape fragmentation due to roads and other linear features. This is resulting in the isolation of populations and increasing vulnerability to predators.17, 23-25 Overharvest of the caribou, fire, and climate change are also considered factors in population decline.17, 18, 26 Generally, populations that are stable or increasing occur in remote areas with little or no industrial activity or where predator control has been used as a management tool.27

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