Goals and Background
For the final project in GIS II, I decided to designated potential areas where a wildlife corridor could be built underneath a road particularly for the Blanding's turtle in Wisconsin. Protecting at-risk species from extinction helps preserve local biodiversity, which in turn, strengthens the health of the local ecosystems. The Blanding's turtle is a protected species and a species of concern in Wisconsin, threatened by habitat fragmentation from encroaching road development.
Starting with the entire state, the analysis will narrow in to one county for further analysis of suitable roads for the installation of a wildlife corridor.
Starting with the entire state, the analysis will narrow in to one county for further analysis of suitable roads for the installation of a wildlife corridor.
Methods
The process started with reprojecting the land cover raster data and Blanding's turtle distribution raster data to NAD 1983 HARN Wisconsin (US feet). The ecological systems field of the land cover data was reclassified to designate all wetland related land types as 1 (the rest as 0). Then the Blanding's turtle distribution data was reclassified to a single value of 1. The two reclassified rasters were multiplied in a Boolean raster operator and overlayed in a raster of likely turtle habitat. The original land cover raster was reclassified to designate grassland and meadow-like habitats, likely nesting habitat, to a value of 1.
Polygons of Wisconsin counties were used as zones for zonal statistics for the sum of cells valued as turtle habitat. Using the identity tool, it turns out that Marinette County contained the most turtle habitat. The turtle habitat raster and nesting site raster were subsequently clipped to a polygon of Marinette County. A Marinette road shapefile was added to the display and processed through a 1620 m (maximum distance the turtle will travel from habitat to nesting sites) Euclidean Distance tool. The distance from 0 to 114 m (area of relatively high turtle traffic) was then reclassified to a value of 1 and then converted into a polygon. Then, the road data was intersected to create points where the lines crossed. Afterward, the points were used to split the road data where it intersects the polygon. It was then possible to select road sections that were contained within the 144 m polygon. Lastly, the selected roads that were merely slivers or did not significantly cross swaths of turtle habitat were deleted as they would not make likely candidate for the location of a highly utilized corridor. Figure 1 displays the results.
Polygons of Wisconsin counties were used as zones for zonal statistics for the sum of cells valued as turtle habitat. Using the identity tool, it turns out that Marinette County contained the most turtle habitat. The turtle habitat raster and nesting site raster were subsequently clipped to a polygon of Marinette County. A Marinette road shapefile was added to the display and processed through a 1620 m (maximum distance the turtle will travel from habitat to nesting sites) Euclidean Distance tool. The distance from 0 to 114 m (area of relatively high turtle traffic) was then reclassified to a value of 1 and then converted into a polygon. Then, the road data was intersected to create points where the lines crossed. Afterward, the points were used to split the road data where it intersects the polygon. It was then possible to select road sections that were contained within the 144 m polygon. Lastly, the selected roads that were merely slivers or did not significantly cross swaths of turtle habitat were deleted as they would not make likely candidate for the location of a highly utilized corridor. Figure 1 displays the results.
Results
Plenty of roads sections make suitable locations for a potential wildlife corridor for the Blanding's turtle. For some reason, not all of the roads were selected that were within the 114 m polygon. This might have something to due with problems with intersecting or splitting the roads. Turtle habitat adjacent to selected roads could hypothetically be surveyed for the presence of turtle population to determine the validity of the selection.
Figure 1: Map of potentially suitable site to install a wildlife corridor.
Sources
Data
Bibliography
Wisconsin Land Cover - U.S.
Geological Survey Gap Analysis Program, 2013, GAP/LANDFIRE National Terrestrial
Ecosystems 2011: U.S. Geological Survey. https://gis1.usgs.gov/csas/gap/viewer/land_cover/Map.aspx
Blanding’s Turtle Distribution – U.S.
Geological Survey Gap Analysis Program, 2016, U.S. Geological Survey Gap
Analysis Program Species Distribution Models: U.S. Geological Survey. https://gapanalysis.usgs.gov/species/data/download/
Marinette County Roads – Marinette County Land
Information Office, 2017, Roads Marinette County, WI 2017: UW – Madison. http://maps.sco.wisc.edu/opengeoportal/
Wisconsin Counties – Price, H. M., 2016, Counties: Mastering ArcGIS - McGraw-Hill
Education.
Bibliography
Bury, R. B., & Germano, D. J. (2002). Differences in Habitat Use by
Blanding's Turtles, Emydoidea blandingii, and Painted Turtles, Chysemys picta, in the
Nebraska Sandhills. The American Midland Naturalist , 241-244.
Joyal, L. A., McCollough, M., & Hunter Jr. , M. L. (2001). Landscape
Ecology Approaches to Wetland Species Conservation: A Case Study of Two Turtle
Species in Southern Maine. Conservation Biology , 1755-1762.
Proulx, C. L., Fortin, G., & Blouin-Demers, G.
(2014). Blanding's Turtles (Emydoidea blandingii) Avoid Crossing Unpaved and Paved Roads. Journal of Herptology , 267-271.
Ross, D. A., & Anderson, R. K. (1990). Habitat
Use, Movements, and Nesting of Emydoidea blandingi in Central Wisconsin. Journal of Herptology , 6-12.
