Grassland graphic descriptors
Historical loss of grasslands
This graphic includes a map and five pie charts. The map shows the approximate historical distribution of grasslands in Canada, which is concentrated in five areas. The pie charts show theestimated percent loss of grasslands up to the early 1990s in each of the five areas. All five show declines in the extent of grasslands, with tall grass prairie showing the greatest loss.
Each pie chart is described in the following set of points:
- Prairie grasslands. Historically covering the Prairies and the southern portion of the Boreal Plains Ecozone+, approximately 70% was lost by the 1990s (reference 4).
- Tallgrass prairie. As it occurs in two separate areas, two pie charts are used to illustrate the loss of tallgrass prairie. Greater than 99% of the small historic distribution in the southeastern part of the Prairies was lost by 1989 (references 9, 14 and 15) and greater than 97% of the small patches of tallgrass and savannah, historically scattered throughout southeastern Ontario, were lost by 1992 (references 10 and 16).
- Bunchgrass and sagebrush. Historically occurring in southcentral and southeastern British Columbia, two pie charts illustrate the declines in these areas prior to 1990, which are 15 and 19% respectively (references 11 and 12).
Canadian grassland birds
This line graph shows the trend in breeding grassland bird populations in Canada from 1967 to 2006. Each point represents the annual index of abundance based on all grassland species. While fluctuating slightly annually, the graph shows a significant, steady, steep decline from a peak of 89 on the abundance index in 1969 to a low point of 43 in 2002. Although increasing since 2002 to 50, in 2006 the overall trend remains a significant steep decline.
Degree of alteration of Saskatchewan grasslands due to grazing
This bar graph shows the degree to which Saskatchewan grasslands had been altered as a result of grazing by 2007. Twelve percent were severely altered, 35% were moderately altered, and 29% had only minor alterations.
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