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

Western Interior Basin Ecozone+

Agricultural landscapes

At lower elevations of the Western Interior Basin, grazing, forage production, and orchards were common while woodland grazing was associated with middle elevations. Over twenty years (1986 to 2006), the agricultural landscapeFootnote22 in the Western Interior Basin expanded from 482,000 to 570,000 hectares to make up approximately 10% of the ecozone+ (Figure 38). Figure 39 shows the total agricultural land area and the amount of land per each agricultural cover type in 1986, 1996, and 2006. Unimproved Pasture was the dominant land cover in the ecozone+ increasing its share from 64 to 67% of total agricultural land over 20 years. The share of Tame Hay expanded (4 to 11%) while declines were associated with Improved Pasture (9 to 5%) and All Other Land (18 to 12%). Overall, the share of CroplandFootnote23 expanded by 6% to make up 15% of agricultural land.

Figure 38. The percentage of agricultural land within the Soil Landscapes of Canada(SLC) polygons of the Western Interior Basin Ecozone+, 2006.

map

Long Description for Figure 38

This map shows the percentage of agricultural land within the SLC polygons of the Western Interior Basin Ecozone+ in 2006. The agricultural landscape makes up approximately 10% of the ecozone+ (570,000 hectares).

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Figure 39. Total agricultural land area, the amount of land per cover type (chart), and the relative percentage of each cover type (table) for the Western Interior Basin Ecozone+ for 1986, 1996, and 2006.

graph

Long Description for Figure 39

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

Percentage of agricultural land (hectares)
Cover Type198619962006
Oilseeds474195849
Pulses142162404
Soybeans000
Berries83165163
Improved Pasture42,15142,12930,699
All Other Land84,26793,23268,850
Summerfallow5,9653,0702,199
Unimproved Pasture306,207312,398381,413
Cereals5,3008,3187,284
Corn2,3871,7862,297
Tame Hay20,84354,63564,114
Other Crops370748662
Fruit Trees11,5049,6429,322
Vegetables814804712
Winter Cereals1,338916786

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The majority of agriculture (81%) in the Western Interior Basin Ecozone+ occurred in the Thompson-Okanagan Plateau Ecoregion over the 20 years. The dominant land cover; Unimproved Pasture gained a greater share of agricultural land (63 to 66%) as did Tame Hay (5 to 12%). Declines were associated with All Other Land (18 to 13%) and Improved Pasture (5 to 2%). The Cropland portion of the agricultural landscape expanded from 9 to 15% of the ecoregion.

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Potential wildlife use of agricultural land

A total of 323 terrestrial vertebrates (232 birds; 72 mammals; 10 reptiles; 9 amphibians) were associated with agricultural land in the Western Interior Basin Ecozone+. All Other Land was the most species rich habitat as it was used by 85% (276) of species for both breeding and feeding habitat. The dominant agricultural land cover (Unimproved Pasture) fulfilled both breeding and feeding requirements of 25% (80) of species while providing a single habitat requirement (either breeding orfeeding) for 44% (142). Only 12% (37) of species were able to use Cropland for both breeding and feeding habitat while 25% (82) were able to obtain a single habitat requirement.

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Wildlife habitat capacity

Average wildlife habitat capacity on agricultural land in the Western Interior Basin Ecozone+ showed a significant declining trend among reporting years (ANOVA; F = 22.1, p<0.05) dropping from 70.4 ± 10.9 in 1986 to 61.3 ± 7.3 in 2006 (Figure 40). Figure 41 and Figure 42 show the spatial distribution of habitat capacity values for 1986 and 2006. Over this time period, habitat capacity decreased significantly on 35% of agricultural land, increased on 7%, and was constant on 58% (ANOVA, Tukey HSD p<0.05 ) (Figure 43).

Figure 40. The share of agricultural land in each habitat capacity category (bars, left axis) and the average habitat capacity for the Western Interior Basin Ecozone+ in 1986, 1996, and 2006 (points and line, right axis).

graph

Long Description for Figure 40

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
<200.000.000.00
20-300.000.450.00
30-400.000.000.46
40-500.933.132.70
50-6032.1319.8969.42
60-7028.5347.5822.92
70-8027.9117.203.61
80-907.9210.260.49
90-1002.301.490.23
>1000.280.000.16

The average habitat capacity for the Western Interior Basis Ecozone+ was 70.37 in 1986, 65.44 in 1996 and 61.26 in 2006.

Years with different letters differed significantly (ANOVA: F = 22.1, Tukey HSD p<0.05).

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Figure 41. Wildlife habitat capacity on agricultural land in the Western Interior Basin Ecozone+, 1986.

map

Long Description for Figure 41

This map shows wildlife habitat capacity on agricultural land in the Western Interior Basin Ecozone+ in 1986. High and moderate wildlife habitat capacity is shown across most of the agricultural landscape, with some scattered regions in the very high category.

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 42. Wildlife habitat capacity on agricultural land in the Western Interior Basin Ecozone+, 2006.

map

Long Description for Figure 42

This map shows wildlife habitat capacity on agricultural land in the Western Interior Basin Ecozone+ in 2006. Moderate wildlife habitat capacity dominates the agricultural landscape, with exception of the Okanagan Lake region, which shows high wildlife habitat capacity.

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 43. Change in wildlife habitat capacity on agricultural land in the Western Interior Basin Ecozone+ between 1986 and 2006.

map

Long Description for Figure 43

This map shows the change in wildlife habitat capacity on agricultural land in the Western Interior Basin Ecozone+ between 1986 and 2006. Over this time period, habitat capacity decreased significantly on 35% of agricultural land, increased on 7%, and was constant on 58%.

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

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Interpretation

Agricultural land in the Western Interior Basin Ecozone+ is dominated by Unimproved Pasture which is of considerable value as wildlife habitat, ranking second only to All Other Land. Declining wildlife habitat capacity was primarily related to almost 6% loss of All Other Land reducing its share to just over 12% of agricultural land. In addition, the share of Improved Pasture dropped from 9 to 5% of agricultural land. These combined losses represented a shift of agricultural land from comparatively higher to lower quality wildlife habitat, as the share of Cropland expanded from 9 to 15%. The expansion of Cropland was mainly due to an increase in the share of Tame Hay from 4 to 11%.

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Footnotes

Footnote 22

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).

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Footnote 23

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

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