Technical Thematic Report No. 14. - Trends in wildlife habitat capacity on agricultural land in Canada, 1986-2006
For proper interpretation, it must be noted that agricultural landscapes are dynamic, with beneficial and detrimental land cover change often happening concurrently, especially when analyzed at broader spatial scales. The nature of these changes and the resulting land cover mosaic determined the habitat capacity of the landscape and the structure of wildlife communities. Different wildlife species may have different, yet concurrent responses to land cover change. Certain species dependant on a particular habitat would be negatively affected by its loss, while other species may benefit from the newly created land cover. Also, an expanding agricultural landscape initially added natural/semi-natural land that, through time, will be brought under production. So, when assessed at broad-scales, expanding agriculture with its inherently higher natural land content, counterbalanced declining natural habitat in more established areas within the agricultural landscape. Because areas experiencing gains and losses were spatially explicit, proportional constancy of a particular land cover type (habitat) represented at broader spatial scales (nationally or ecozone+) did not capture the impact of habitat change on wildlife at finer scales (regionally or locally).
Comparative value of land cover types used by wildlife in the Canadian agricultural landscape
Figure 1 provides comparative breeding and feeding values of land cover types used in the habitat capacity analysis. The value of a particular land cover type was based on the number of species it supported and its habitat value to them (that is, whether it was primary, secondary, or tertiary). All Other Land (which included woodland, wetland, and riparian areas) ranked highest, followed by Unimproved Pasture (natural land for pasture); demonstrating the importance of these natural/semi-natural land cover types for wildlife. Improved Pasture, Tame Hay, and Fruit Trees ranked next but had a marked decline in their value as both breeding and feeding habitat. Cultivated landsFootnote 6 were characterized by comparatively low value for wildlife, especially in terms of breeding habitat.
The value of All Other Land is further emphasized when one considers that 75% (440) of species that use agricultural land in Canada can fulfill both their breeding and feeding habitat requirements entirely within the natural/semi-natural lands contained within this land cover category. In contrast, only 13% (79) of species can fulfill both breeding and feeding requirements on Cropland habitats.Footnote 7 When other land cover types (primarily All Other Land/Unimproved Pasture) are present in the agricultural landscape, however, the value of cultivated land for wildlife increases dramatically as 36% (203) of species utilize Cropland for a single habitat requirement (either breeding or feeding). A total of 29% (173) of species could use Unimproved Pasture for both breeding and feeding habitat. When other land cover types are present to provide for a single habitat requirement, 48% (282) of species could then utilize Unimproved Pasture. This demonstrates that the value of certain cover types can fluctuate based on the presence of complimentary habitats that fulfill partial life history requirements. Therefore, the maintenance of heterogeneous agricultural landscapes can often benefit wildlife.
Figure 1. Comparative value of cover types used by wildlife for breeding (top) and feeding (bottom) on agricultural land in Canada.
Long Description for Figure 1
This graphic presents two bar graphs comparing value of cover types used by wildlife for breeding (top) and feeding (bottom) on agricultural land in Canada. All Other Land (which included woodland, wetland, and riparian areas) ranked highest, followed by Unimproved Pasture (natural land for pasture), demonstrating the importance of these natural/semi-natural land cover types for wildlife. Improved Pasture, Tame Hay, and Fruit Trees ranked next but had a marked decline in their value as both breeding and feeding habitat. Cultivated lands were characterized by comparatively low value for wildlife, especially in terms of breeding habitat.
The scale on the x-axis is the sum of the habitat values.
- Footnote 6
Cultivated land includes Summerfallow and annual crops (Oilseeds, Pulses, Soybeans, Cereals, Corn, Tame Hay, Other Crops, Vegetables, and Winter Cereals).
- Footnote 7
Cropland includes all agricultural land except for All Other Land, Unimproved Pasture, Improved Pasture, and Summerfallow.
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