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Maps of Mountain Lion Sightings in Wisconsin
John
Severson
Ryan
Walker
These maps have been derived from data collected by the Wisconsin Department
of Natural Resources (A. Wydeven and J. Wiedenhoeft) on rare mammal
observation cards (Fig 1) gathered throughout the state. Each
observation was assigned one of three probability ratings: probable,
possible, or not likely. Observations with not likely ratings were
removed from the sample. The criteria for the assignment was arbitrary
but was based on sign (tracks, scat, visual sighting, etc.), credibility of
the observer, and assessment by the DNR.
Methods
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We received the
Wisconsin 1994-2003 cougar sightings as an Excel spreadsheet from Adrian
Wydeven and Jane Wiedenhoeft of the Wisconsin Department of Natural
Resources. We excluded the not likely data as they were probably
not cougar sightings.
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The legal description
was converted to Direction Township Range Section (DTRS) code. The
DTRS is a seven-digit number that begins with the direction from a central
meridian that divides the state. West of the meridian is 2, and East
is 4. This is followed by a series of two-digit numbers for
township, range, and section. If a section was not given, the value
of 16 was given because this is near the center of the township. If
only the county was given, the Xtools extension of ArcView, was used to
determine the center of the county using the convert shapes to centroids
function, which was used for the DTRS data. One observation for
Florence County had a township that did not exist in Wisconsin, so that
data point was excluded. We then had 345 observations.
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Weighted values were
added to the file in another column using 1 for possible sightings,
and 5 for the probable sightings. The Excel file was then saved
as a database file (.dbf).
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We opened the
Wisconsin DTRS polygon shapefile, using ArcView 3.3. This file was
obtained from the Oasis Website maintained by the UWSP College of Natural
Resources (http://oasis.uwsp.edu/).
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We joined the cougar
database file to the DTRS database file. All the section data from
the joined file that did not have cougar data were deleted. This
allowed us to get a polygon file with only the sections with sightings.
However, data from sections with more than one sighting were reduced to
one sighting, bringing our total to 333 observations.
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Using Xtools convert
shapes to centroids, we converted the section polygons to points located
at the center of the section. Point shapefiles were created for
every combination of five consecutive years (1994-1998, 1995-1999, etc.),
as well as the cumulative data for all 10 years.
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Neighborhood
Statistics was used from the Spatial Analyst extension to analyze all the
data. The output grid extent was set at Same as display. The
grid cell size was set at 500 m. Grid cell size needed to be less
than the minimum distance between two points. The output grid cell
size was left As specified below. The row and column settings were
left as default. The statistic used was sum. The neighborhood
used was circle. The radius was set at 10,000 m and the units were
set to distance.
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The Neighborhood
Statistics file was converted to a shapefile.
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This shapefile was
then converted to a Triangulated Irregular Network by using the create
TIN from features function. The height source was set to
Gridcode. Input as soft clip polygons. Value field is
Gridcode.
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Layouts were created
using the Neighborhood Statistics, TIN, and Cougar Sightings data.
Maps
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Aggregated Mountain Lion
Sighting Occurrence in Wisconsin from 1994-2003 |
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| ALL Mountain Lion Sightings in
Wisconsin from 1994-2003 |
Accumulated Weighted Mountain Lion
Sightings in Wisconsin from 1994-2003 |
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Accumulated Weighted
Mountain Lion Sightings in Wisconsin from 1994-1998 |
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Accumulated Weighted
Mountain Lion Sightings in Wisconsin from 1995-1999 |
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Accumulated Weighted
Mountain Lion Sightings in Wisconsin from 1996-2000 |
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Accumulated Weighted
Mountain Lion Sightings in Wisconsin from 1997-2001 |
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Accumulated Weighted
Mountain Lion Sightings in Wisconsin from 1998-2002 |
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Accumulated Weighted
Mountain Lion Sightings in Wisconsin from 1999-2003 |
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