How
did the Rodeo-Chedeski fire impact the mule
deer population? |
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Background:
The Rodeo-Chedeski fire is the largest fire recorded in Arizona, burning
over 468,000 acres of forest habitat in less than one-month in June
2002. Effects of a catastrophic fire concern biologists because they
can be detrimental to the habitat and its inhabitants. Post fire effects
can be even more severe when they impact already declining populations,
but there are also circumstances where fires can help.
Western US mule deer populations have declined significantly over the past
20 years with several probable reasons for decline. One reason often cited
is the decline in suitable forest habitat. Mule deer density and distribution
varies depending on forest habitat quality, which is directly linked to
the amount of cover and quality of vegetation.
Arizona ponderosa pine forests burned every 2 to 8 years before European
settlement, and these natural lightning strike fires increased vegetation
diversity. Tree density was much lower than it is today, so when fires
did occur, they were cooler. Research indicates cooler fires often stimulate
browse growth, create openings in dense stands, and increase the nutritional
content of forage. Although the Rodeo Chedeski was very severe below the
Mogollon Rim, the high speed of the fire above the rim left a mosaic of
unburned (7%) and lightly burned habitat (40%), while 53% of the area was
moderately to heavily burned. We will examine how mule deer use the different
severities of burned habitats in the Rodeo-Chedeski area.
Location:
We will conduct the project on the Apache-Sitgreaves
National Forest in the eastern portion of the
burn. The project will extend as far north
as Highway 260, east to Forest Service road
(FR) 146, south to the Fort Apache Indian Reservation,
and west to FR 168.
Approach:
We will capture female mule deer and collar
them with GPS radio-collars that record a minimum
of 5 locations a day. This new technology allows
us to collect much more information than ever
before without us being there and influencing
their movements. We will use satellite imagery
and remote sensing to create a GIS vegetation
cover map that will help us identify habitat
differences. We will examine mule deer habitat
use in patches of different burn severities
to determine how the Rodeo Chedeski fire influenced
female mule deer behavior.
Benefits:
An increase in the number of catastrophic fires
has caused a broad scientific, social, and
political consensus that restoration of ecological
sustainability in southwestern pine forests
is necessary and urgent. Recently, the President
proposed categorical exclusion from the National
Environmental Policy Act (NEPA-Healthy Forest
Initiative) for forest thinning projects, and
annual treatments are now proposed for >81,000
ha in Arizona and New Mexico. Numerous treatments
and techniques from mechanical to burning are
planned to reduce tree density, and results
may mimic the heterogeneous landscape left
by the Rodeo Chedeski Fire. Reducing tree density
at landscape scale areas could positively influence
mule deer by increasing early successional
stage habitat rather than later stages, when
most nutrients are used up by woody material.
However, the optimal area to be thinned and/or
burned, and the cover that needs to be left
needs to be determined so that mule deer can
escape heat and predation. We hope that studying
the response of mule deer to a mosaic of burned
habitat patches will provide specific suggestions
to design future forest thinning projects soon
to occur under the Healthy Forest Initiative.
Hopefully, these suggestions will benefit and
increase mule deer numbers in what is currently
poor quality habitat.
For more information
contact:
Stan Cunningham, Arizona Game and Fish Department, 5000 W. Carefree Highway Phoenix, AZ 85086-5000
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