Proceedings of the Ninth Mountain Lion Workshop - Carnivore ...

ural areas (hereafter, developed zone) of the same region. We tested whether
anthropogenic and natural barriers limited puma movements and, thus, connectivity
within landscapes. Finally, we examined whether developed-zone pumas preferentially
used or avoided diminishing size-classes of residential property parcels within animals’
home range areas. We asked whether pumas’ use of parcels by size differed between day
and night, suggesting responses to human activity levels. We focused on this wideranging
species to identify threats to habitat connectivity likely to impact local wildlife
communities (Noss et al. 1996, Terborgh et al. 1999), and to facilitate regional
conservation planning.
Study area
We conducted this study in Sierra, Nevada, Placer, El Dorado and Amador counties, in
California’s western Sierra Nevada Mountains and foothills. The western portion of
these adjoining rural counties borders the agricultural Central Valley and the Sacramento
metropolitan area. Elevation ranges from sea level in the west to over 2500 m at the
Sierra Nevada crest. River canyons running roughly east-west separate mountain ridges
in the higher elevations. Most private and residential lands are in the western foothills,
characterized by oak-dominated (Quercus sp.) woodlands and chaparral. Eastward,
vegetation transitions with rising elevation to conifer forests. This area is primarily nonresidential
timberlands, networked by logging roads. An urban/wildland interface
corresponding to housing density on private versus public lands, typically national
forests, transected our study area and was used to define the “developed” versus
“undeveloped zone” (Fig. 1). Most of the counties’ areas provide puma habitat,
excluding only valley agricultural lands, urban areas, and the high elevation zones of the
Sierra crest.
The area supports populations of mule deer (Odocoileus hemionus), black bear (Ursus
americana) and puma, but represents a region of ecological concern. Large, contiguous
regions at high elevations are protected from land conversion as national forests,
wilderness and other public land designations, while other areas are privately managed
timberlands. In contrast, the western foothills are largely privately owned. Traditional
grazing land is being converted to ranchette-style settlement, or other uses such as
vineyards and orchards. The area is intersected north-south by high-traffic highways US
Route 50 and I-80, which serve as corridors for development emanating from the
Sacramento metropolitan area.
Placer County had the fastest growing human population in California with a projected
27.6% increase from 2000 to 2005 (US Census Bureau 2007). Population increased by
9.6%, 13.1%, and 6.9% in Amador, El Dorado, and Nevada Counties respectively, during
the same period. In Nevada County, the amount of undeveloped land zoned for
residential or commercial development was 3.5 times the county’s developed land area
(Walker et al. 2003). Over 60% of El Dorado County’s undeveloped private land was
zoned for residential (0.4 to 8-ha or 1- to 20-acre) or exurban (8- to 16-ha or 20- to 40acre)
development (Stoms 2004). In Placer County, 93% of the foothills were privately
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