Lab number 4 examined a situation where multiple criteria needed to be met in order to satisfy the predetermined requirements established to find suitable bear study areas. These predetermined objectives included the popular forest types bears are found if they are near streams. Then it was necessary to find areas that satisfied both those criteria and additionally areas that are managed by the DNR and are at least 5 km from urban or built up lands. A numbered list of objective steps is as follows:
1. To map a GPS MS Excel file of black bear locations in Michigan
2. To determine the forest types where black bears are found in central Marquette County, Michigan based on GPS locations of black bears.
3. To determine if bears are found near streams.
4. To find suitable bear habitat based on two criteria.
5. To find all areas of suitable bear habitat within areas managed by the Michigan DNR.
6. To eliminate areas near urban or built up lands.
7. Generate cartographic output
8. Generate a digital data flow model of the procedures used to determine suitable bear habitat in Marquette County, Mi
Following these steps will allow us to use various geoprocessing tools in vector analysis to gain our desired result of suitable bear habitat areas for bears in an area of Marquette County in the state of Michigan.
Methods:
Determining that 49 of the 68 bears located were within 500 meters of a stream was done by a join of the bear locations feature with streams feature. Since this amounts to well over thirty percent, it told us this was an important feature and we should map it in our final resulting answer. Also, it is necessary to create a new layer of the three most populated forest types: Mixed Forest Land, Forested Wetlands, and Evergreen Forest Land. This can be done by a summary of a join between bear location and landcover. To determine the areas that satisfy both those requirements, buffer the streams and dissolve all. Next, to find land suitable for both requirements, intersect the created forest layer with the stream buffer layer and dissolve the result. To determine which parts of the area you have found is in DNR managed area, you will need a few steps. First, add the DNR management layer to the data frame. Then clip that to the study area layer to only examine the DNR land in our area of interest. Next, dissolve the DNR layer and intersect it with the previous suitable area followed by a dissolve of the resulting area after the intersection. Finally, to satifsfy our last requirement of getting rid of the area within our suitable result that is 5km or less from urban or built up areas, first select urban and built up areas and create a layer from the selected features. Dissolve the new layer. Finally, use the erase tool to erase this new layer from the most recent suitable area layer. Figure 1. shows a data flow model of these steps and how the final answer is reached.
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| Figure 1. Data Flow Model |
Results:
After all the analysis has been completed, a map of Marquette County, Michigan, showing bear location, streams, all suitable habitat, and suitable habitat that was eliminated from its proximity to urban and built up areas (Figure 2.). It appears as if the majority of suitable bear habitat falls within the southwestern area of our overall study area.
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| Figure 2. Final Map |
Sources:
http://www.mcgi.state.mi.us/mgdl/nlcd/metadata/nlcdshp.html
http://www.dnr.state.mi.us/spatialdatalibrary/metadata/wildlife_mgmt_units.htm
http://www.mcgi.state.mi.us/mgdl/framework/metadata/Marquette.html
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