Module 1, Part 2: Corridor Analysis
The purpose of this lab was to create a corridor of potential movement of black bears between two protected areas in the Coronado National Forest. The variables for the analysis included distance to roads, elevation and land cover. The flow chart for the work flow in this analysis is below:
In order to begin the corridor development, I first developed a habitat suitability model. I began by reclassifiying the roads shapefile and elevation and landscape rasters. The rasters were reclassified using the Reclassify tool with the cost values provided. The roads shapefile was first converted to a raster using the Polyline to Raster tool, then using the Euclidean Distance tool to identify distances away from the road within the elevation raster’s extent, then using the Reclassify tool with the cost values provided. The habitat suitability model was then developed using the Weighted Overlay tool with all three reclassified rasters, weighted with landcover at 60% and elevation and roads at 20% with 10 classes.
To create a cost model, the habitat suitability model was inversed using the Reclassify tool and subtracting 10 from the values in the model raster. The Cost Distance tool was used with the inversed habitat suitability model to create two cost distance rasters, first with Coronado 1 as the source and then with Coronado 2 as the source.
The final corridor was created using the Corridor tool with the two cost distance rasters as the inputs. I determined the threshold values for the corridor by examining the minimum and maximum values as well as the standard deviations. I multiplied the minimum value by 1.15 and increased by 0.15 for each other threshold values. Although wide, these values appeared to result in a corridor that best represented the black bear movement without being too wide.
The corridor analysis shows a wide area that is suitable for movement between the two conservation areas, with some areas having higher suitability ratings than others. The corridor analysis reveals clear areas through which black bears are likely to move (red area). Because this analysis weighted land cover higher than other variables, this area must have more suitable land cover for black bears. Even though there are also many roads in this area, the corridor analysis shows this area to be suitable for bear movement because of the land cover type. There are also distinct areas that resemble alternative paths (orange areas), which are suitable for black bear movement.
Overall, corridor analysis is valuable for determining areas suitable for a variety of issues from wildlife movement to routes for installation of infrastructure that involve multiple variables.
In order to begin the corridor development, I first developed a habitat suitability model. I began by reclassifiying the roads shapefile and elevation and landscape rasters. The rasters were reclassified using the Reclassify tool with the cost values provided. The roads shapefile was first converted to a raster using the Polyline to Raster tool, then using the Euclidean Distance tool to identify distances away from the road within the elevation raster’s extent, then using the Reclassify tool with the cost values provided. The habitat suitability model was then developed using the Weighted Overlay tool with all three reclassified rasters, weighted with landcover at 60% and elevation and roads at 20% with 10 classes.
To create a cost model, the habitat suitability model was inversed using the Reclassify tool and subtracting 10 from the values in the model raster. The Cost Distance tool was used with the inversed habitat suitability model to create two cost distance rasters, first with Coronado 1 as the source and then with Coronado 2 as the source.
The final corridor was created using the Corridor tool with the two cost distance rasters as the inputs. I determined the threshold values for the corridor by examining the minimum and maximum values as well as the standard deviations. I multiplied the minimum value by 1.15 and increased by 0.15 for each other threshold values. Although wide, these values appeared to result in a corridor that best represented the black bear movement without being too wide.
The corridor analysis shows a wide area that is suitable for movement between the two conservation areas, with some areas having higher suitability ratings than others. The corridor analysis reveals clear areas through which black bears are likely to move (red area). Because this analysis weighted land cover higher than other variables, this area must have more suitable land cover for black bears. Even though there are also many roads in this area, the corridor analysis shows this area to be suitable for bear movement because of the land cover type. There are also distinct areas that resemble alternative paths (orange areas), which are suitable for black bear movement.
Overall, corridor analysis is valuable for determining areas suitable for a variety of issues from wildlife movement to routes for installation of infrastructure that involve multiple variables.
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