Wildlife and Roads: Decision Guide Step 2.1.3

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2.1.1: Identify Species to Benefit from Potential Mitigation

2.1.2: Identify Ecological Processes (Water Flow, Animal Movement, Other)

2.1.3: Identify Landscape and Topographic Features That May Affect Movement and Mitigation

2.1.4: Identify Engineering and Maintenance Concerns

2.1.5: Weigh Cost Concerns with Potential Benefits

2.1.6: Identify Appropriate General Wildlife Crossing Type

2.1.7: Other Mitigation Options

2.1.8: References

2.1.3. Identify Landscape and Topographic Features That May Affect Movement & Mitigation

An important consideration in the selection of a wildlife crossing is the topographic relief of an area and the landscape features near the road. Wildlife typically prefer to approach a road crossing while following a natural feature such as a ridgeline, low lying riparian area, or a corridor of vegetation where they feel safe. Paying special attention to where these features occur near a potential mitigation site will not only assist in selecting what mitigation type is best suited for the area, but also help to ensure the successful movement of animals through the landscape to the crossing. Topographic features such as deep water or a steep canyon wall may also serve to prevent wildlife from entering the roadway. These areas can be used as possible "guiding" features. Placement of the crossing may be as important as the type of crossing, so the consideration of landscape and topographic features is critical. A field visit is the best way to be able to judge these characteristics of the landscape. The best way to evaluate the placement of crossings (Step 2.2) would involve wildlife crossing data, and a field visit coupled with expert opinion. Placement is further discussed in Step 2.2.

Decision Guide Overview Step 1: Resource Evaluation Step 2: Identify Solutions Step 3: Select & Create Plan Step 4: Construction Step 5: Monitor & Evaluate The wildlife passage at the base of the hills was located at the northern edge of a mountain range where mule deer and other wildlife preferred moving, rather than through the open sagebrush lands to the north (background in picture). Although the line of site through this passage is less than optimal (wildlife should be able to see that this passage leads to where they want to go), the mule deer in the area have adapted to it and monitoring has found dozens of deer passages every month under the highway bridges. No other mammals have been photographed using this passage in the first four months of monitoring.
The wildlife passage at the base of the hills was located at the northern edge of a mountain range where mule deer and other wildlife preferred moving, rather than through the open sagebrush lands to the north (background in picture). Although the line of site through this passage is less than optimal (wildlife should be able to see that this passage leads to where they want to go), the mule deer in the area have adapted to it and monitoring has found dozens of deer passages every month under the highway bridges. No other mammals have been photographed using this passage in the first four months of monitoring.

A wildlife passage was created when the plans for this bridge along US 93 in Montana were extended to include upland as well as the river. Wildlife typically use riverine areas for movement pathways, especially in steep terrain as in this picture.
A wildlife passage was created when the plans for this bridge along US 93 in Montana were extended to include upland as well as the river. Wildlife typically use riverine areas for movement pathways, especially in steep terrain as in this picture.


2.1.1: Identify Species to Benefit from Potential Mitigation

2.1.2: Identify Ecological Processes (Water Flow, Animal Movement, Other)

2.1.3: Identify Landscape and Topographic Features That May Affect Movement and Mitigation

2.1.4: Identify Engineering and Maintenance Concerns

2.1.5: Weigh Cost Concerns with Potential Benefits

2.1.6: Identify Appropriate General Wildlife Crossing Type

2.1.7: Other Mitigation Options

2.1.8: References