Wetlands

Wetland loss in the Prairies

Graphic thumbnail: Wetland loss in the Prairies

This map shows wetland loss for each of approximately 400 land units in the Prairies between 1985 and 2001. The percent loss is displayed in colour-coded ranges: 0 to 5% loss, 5 to 9%, 9 to 15%, 15 to 25%, and 25 to 45%. Two land units in Manitoba had no data. The majority (65%) of land units had 0 to 5% loss, while four suffered losses of 25 to 45%, and eight suffered losses of 15 to 25%. All 12 are in the eastern half of the ecozone+. Thirty land units had losses of 9 to 15% and 96 showed losses of 5 to 9%. Losses tend to be higher near urban centres. An inset map shows the location of the study area in southern Manitoba, Saskatchewan and Alberta.

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Wetland loss in southern Ontario

Graphic thumbnail: Wetland loss in southern Ontario

This map shows wetland loss for each of 350 townships in southern Ontario from 1800 to 2002. The percent loss is displayed in colour-coded ranges: 0 to 25% loss, 25 to 45%, 45 to 65%, 65 to 85%, and 85 to 100%. Four townships on the northern edge of the study area were unassessed. Wetland loss is extensive, with 80% of townships having lost more than 45% of their wetlands over the time period. Loss was most severe in southwestern Ontario, parts of southeastern Ontario, Niagara, and the Toronto area where loss was from 85 to 100%. Only 5 of the 350 townships showed a loss of less than 25%.

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Change in extent of wetlands along the St. Lawrence River

Graphic thumbnail: Change in extent of wetlands along the St. Lawrence River

This graphic contains two maps showing changes in extent of wetlands over two time periods, generally indicating an overall loss from 1945 to 1978 and gain in the later time period. The first map shows changes in extent of each physiographic unit from 1945 to 1978 through colour-coding according to four categories: 29% loss, 7 to 17% loss, 1 to 6% loss, and no data. Wetland loss occurred in all physiographic units where data existed. The area around Quebec City had the greatest loss at 29%. The Montreal area lost 7 to 17%.

The second map shows changes in extent of physiographic units from1970 to 1978 and 2001 to 2002. This map shows the extent change for each unit as a percent and also groups the changes into three colour-coded categories: wetland gain, stable, and wetland loss. The overall trend was an increase in wetlands. Gains ranged from around 6% west of Montreal to 17% west of Quebec to 12%. Only two areas continued to have a loss -- the areas around Montreal (17% loss) and Lac Saint-Pierre (0.5% loss). The areas east of Quebec City and Cornwall remained stable.

An inset map shows the location of the study area which is the St. Lawrence River between Cornwall, Ontario and east of the Saguenay River, Quebec.

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Old Crow Flats

Graphic thumbnail: Old Crow Flats

This bar graph shows the percent change in surface area of six types of water bodies (ponds, small lakes, medium lakes, large lakes, very large lakes, and all lakes combined) in Old Crow Flats over two time periods, 1951 to 1972 and 1972 to 2001. From 1951 to 1972, all categories had an increase in surface area (ponds increased by 6.9%, small lakes by 10.3%, medium lakes by 7.5%, and large lakes by 4.9%) except very large lakes which decreased by 0.6%. Combined, all lakes had an increase of 1.6%. From 1972 to 2002, surface area decreased in all categories (ponds by 8.5%, small lakes by 1%, medium lakes by 4.9%, large lakes by 8.6% and very large lakes by 3.9%). The surface area of all lakes combined decreased by 5%. An inset map shows the location of the Old Crow Flats in the northern Yukon

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Change in extent of wetlands in the south Okanagan and lower Similkameen Valleys, B.C.

Graphic thumbnail: Change in extent of wetlands in the south Okanagan and lower Similkameen Valleys, B.C.

This bar graph shows the area of wetlands in the south Okanagan and lower Similkameen valleys in 1800, 1938, and 2005. The area of wetlands decreased from 178 square kilometres in 1800 to 69 square kilometres in 1938 to 30 square kilometres in 2005. This represents an 84% loss. An inset map shows the location of the study area in the southcentral interior of British Columbia between north of Vernon and the United States border.

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Peace-Athabasca Delta

Graphic thumbnail: Peace-Athabasca Delta

This map of Canada shows the location of the Peace-Athabasca Delta in northeast Alberta.

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Great Lakes water quality index scores in Canada

Graphic thumbnail: Great Lakes water quality index scores in Canada

This map shows the water quality index scores for wetlands on the Canadian shores of the Great Lakes as a measure of wetland health. Health scores are ranked in six colour-coded categories: excellent, very good, good, moderately degraded, very degraded, and highly degraded. Data for Lakes Ontario, Erie, and Georgian Bay were collected from 2006 to 2009, and data for Lakes Superior and Huron were collected from 1998 to 2005. The map shows that the lower Great Lakes, particularly the western end of lakes Ontario and Erie, had the most degraded sites, with very few sites rated as good and many rated as highly degraded, very degraded, and moderately degraded. Sites in Georgian Bay, Lake Huron, and Lake Superior tended to be in good, very good, or excellent health, with only three sites receiving moderately degraded rankings.

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