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Technical Thematic Report No. 14. - Trends in wildlife habitat capacity on agricultural land in Canada, 1986-2006

Prairies Ecozone+

Agricultural landscapes

The majority of agricultural land in Canada was found in the agriculturally dominated Prairies Ecozone+. Agricultural landscapesFootnote17 comprised close to 93% of the Prairies Ecozone+ in 2006 (Figure 26) and consisted of considerable wheat, cereal, oilseed, and pulse crop production with extensive range and pasture land. The agricultural landscape expanded by approximately 1.3 million hectares between 1986 and 1996 (40 to 41 million hectares) then remained generally stable through to 2006. Figure 27 shows total agricultural land area and the amount of land per each cover type for 1986, 1996, and 2006. Cereals were the dominant cover type in each year despite a decline that occurred between 1996 and 2006 (37 to 29%). Unimproved Pasture was the second most abundant cover type. Over 20 years, the share of Unimproved Pasture declined from 25.4 to 24.5% of agricultural land. The percentage of All Other Land was stable around 5%. Oilseed (6 to 11%), Tame Hay (2 to 8%), and Improved Pasture (4 to 8%) gained an increased share while Summerfallow (18 to 7%) decreased.

Figure 26. The percentage of agricultural land within the Soil Landscapes of Canada (SLC) polygons of the Prairies Ecozone+, 2006.

map

Long Description for Figure 26

This map shows the percentage of agricultural land within the SLC polygons of the Prairies Ecozone+ in 2006. Agricultural landscapes comprised close to 93% of the Prairies Ecozone+.

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Figure 27. Total agricultural land area, the amount of land per cover type (chart), and the relative percentage of each cover type (table) for the Prairies Ecozone+ for 1986, 1996, and 2006.

graph

Long Description for Figure 27

This graphic presents a stacked bar graph showing the following information:

Percentage of agricultural land (hectares)
Cover Type198619962006
Oilseeds2,292,9423,267,7444,565,502
Pulses207,286711,4641,858,122
Soybeans129466127,255
Berries3221,0931,284
Improved Pasture1,564,9172,216,7123,344,178
All Other Land1,845,6392,020,9942,156,590
Summerfallow7,111,0425,497,9083,022,828
Unimproved Pasture10,223,2149,883,83610,080,096
Cereals15,470,85715,377,12511,883,281
Corn36,05139,878113,852
Tame Hay671,9892,020,5373,362,006
Other Crops97,994281,149210,857
Fruit Trees314391
Vegetables27,75130,62522,533
Winter Cereals697,571208,380389,220

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Potential wildlife use of agricultural land

A total of 340 species (245 birds; 71 mammals; 13 reptiles; 11 amphibians) were associated with agricultural land in the Prairies Ecozone+. Land cover represented under the All Other Land category (natural and semi-natural land including wetlands, riparian vegetation, and wooded areas) was extremely important wildlife habitat as 78% (264) of species could use such habitats for both their breeding and feeding requirements. Unimproved Pasture was also valuable wildlife habitat as 30% (103) of species used it for both breeding and feeding while 53% (180) could use it for a single life history requirement. In contrast, only 4% (14) of species were able to utilize CroplandFootnote18 for both these habitat requirements. However, when other suitable habitat was present to provide for partial life history requirements, 32% (110) of species were able to use Cropland.

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Wildlife habitat capacity

In 2006, the average wildlife habitat capacity on agricultural land for the Prairies Ecozone+ was low (43.4 ± 11.5). Despite slight shifts in the relative percentage among habitat capacity categories over 20 years there was no significant change at the ecozone+ level (ANOVA, F = 0.48, p = 0.62) (Figure 28). The spatial distribution of habitat capacity values in 1986 and 2006 are shown in Figure 29 and Figure 30, respectively. Over this period, habitat capacity was constant on 92% of agricultural land, increased on 5%, and decreased on 3% (ANOVA, Tukey HSD p<0.05 ) (Figure 31).

There was considerable wildlife habitat capacity variability among ecoregions within the Prairies Ecozone+. The Moist Mixed Grassland had the lowest habitat capacity (low: 38.0 ± 9.5) while the Cypress Upland reported the highest value (moderate: 61.5 ± 9.8).

Figure 28. The share of agricultural land in each habitat capacity category (bars, left axis) and the average habitat capacity for the Prairies Ecozone+ in 1986, 1996, and 2006 (points and line, right axis).

graph

Long Description for Figure 28

This stacked percentage bar graph shows the following  information:

Habitat capacity Categories

  • Very high 90->100
  • High  70-90
  • Moderate 50-70
  • Low 30-50
  • Very low <20-30
Share of agricultural land per habitat capacity category (percentage)
Habitat capacity
Categories
198619962006
<200.520.400.82
20-3013.3015.3610.80
30-4046.1441.5241.94
40-5022.5725.0926.94
50-607.569.709.82
60-706.634.928.00
70-803.282.881.68
80-900.000.120.00
90-1000.000.000.00
>1000.000.000.00

The average habitat capacity for the Prairies Ecozone+ was 42.94 in 1986, 43.06 in 1996 and 43.43 in 2006.

No significant difference occurred between years (ANOVA: F = 0.43, Tukey HSD p<0.05).

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Figure 29. Wildlife habitat capacity on agricultural land in the Prairies Ecozone+, 1986.

map

Long Description for Figure 29

This map shows wildlife habitat capacity on agricultural land in the Prairies Ecozone+ in 1986. Most of the agricultural land is in the low wildlife habitat capacity category, with an area in the moderate to high range in the southern region around the boarder of Alberta and Saskatchewan.

HC means average Habitat Capacity for the ecoregion. All SLC polygons with >5% agricultural land were included in the analysis.

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Figure 30. Wildlife habitat capacity on agricultural land in the Prairies Ecozone+, 2006.

map

Long Description for Figure 30

This map shows wildlife habitat capacity on agricultural land in the Prairies Ecozone+ in 2006. Most of the agricultural land is in the low wildlife habitat capacity category, with an area in the moderate range in the southern region around the boarder of Alberta and Saskatchewan.

HC means average Habitat Capacity for the ecoregion. All SLC polygons with >5% agricultural land were included in the analysis.

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Figure 31. Change in wildlife habitat capacity on agricultural land in the Prairies Ecozone+ between 1986 and 2006.

map

Long Description for Figure 31

This map shows change in wildlife habitat capacity on agricultural land in the Prairies Ecozone+ between 1986 and 2006. Over this period, habitat capacity was constant on 92% of agricultural land, increased on 5%, and decreased on 3%.

ANOVA, Tukey HSD p<0.05. All SLC polygons with >5% agricultural land were included in the analysis.

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Interpretation

Agriculture is the dominant land use in the Prairies Ecozone+, comprising close to 93% of total land. As such, the population viability and persistence of many species within the ecozone+ depends on the availability of suitable habitat on agricultural land. Between 1986 and 2006, the share of cultivated landFootnote19 declined from 66 to 62% of total agricultural land based largely on the reduction of Summerfallow. However, cultivated land still represented a considerable portion of the agricultural landscape that offered comparatively little in the way of wildlife habitat as the vast majority of species required natural or semi-natural land cover to fulfill breeding and/or feeding requirements. Therefore, cover types such as Unimproved Pasture and All Other Land, which together accounted for less than 30% of agricultural land, played a crucial role in determining the viability of wildlife populations in this ecozone+. The relatively small percentage of these important cover types, which included only 5% All Other Land, was the primary reason for the overall low habitat capacity in the Prairies. At the ecozone+ level, Unimproved Pasture declined by just under 1%. The loss was generally the result of "squaring the field” although large blocks of native grassland habitat were occasionally removed (Watmough and Schmoll, 2007). The share of All Other Land was constant as cumulative losses were not detected at such a broad spatial scale. Watmough and Scholl (2007) estimated a 5% decline in natural wetland area between 1985 and 1996 with the average size of lost wetland basins equaling 0.2 hectares. The loss of such important habitats, although relatively small, represents a considerable degradation of the landscape as wildlife habitat.

The Moist Mixed Grassland had the lowest habitat capacity which resulted from a relatively small share of Unimproved Pasture (19%) and All Other Land (4%). Close to 65% of agricultural land in the ecoregion was cultivated and offered little in the way of wildlife habitat. Although the Aspen Parkland and Lake Manitoba Plain registered similar percentages of Unimproved Pasture and cultivated land, habitat capacity was slightly higher as All Other Land attained it greatest share of agricultural land (8%) in these ecoregions. Despite low All Other Land in the Mixed Grassland and Fescue Grassland, habitat capacity was higher than the previously mentioned ecoregions due to a higher share of Unimproved Pasture which in part contributed to a 12% lower share of cultivated land. The Cypress Upland had the highest wildlife habitat capacity (moderate) primarily due to its extensive Unimproved Pastures which comprised close to 62% of agricultural land in the ecoregion. All Other Land, however, made up less than 3% of total agricultural land limiting habitat options for many species.

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Footnotes

Footnote 17

The agricultural landscape (or agricultural land), as discussed throughout this report, includes the "All Other Land” category from the Census of Agriculture, which is made up of areas such as wetlands, riparian zones, shelterbelts, woodlands, idle land/old fields, and anthropogenic areas (farm buildings, green houses, and lanes).

Return to reference 17

Footnote 18

Cropland includes all agricultural land except for All Other Land, Unimproved Pasture, Improved Pasture, and Summerfallow.

Return to reference 18

Footnote 19

Cultivated land includes Summerfallow and annual crops (Oilseeds, Pulses, Soybeans, Cereals, Corn, Tame Hay, Other Crops, Vegetables, and Winter Cereals).

Return to reference 19