the cougar in the santa ana mountain range, california

Dirt roads (closed to motor vehicles at night)
leading to either end of the overpass would
further enhance the corridor, because cougars
and other animals often to use such roads to
travel through woody vegetation. Such roads
would also allow the overcrossing to be used by
hikers and equestrians. This option should also
include freeway fencing and preventing
urbanization along the ridge east ofthe crossing
point. This option is novel but may be
appropriate given this region's accelerating
urbanization.
4. Import animals into the Santa Ana
Mountain Range. When a cougar enters a
residential area without posing a threat to
human property or safety, the current policy of
California Department of Fish and Game
(CDFG) is that the animal is captured and
moved to the nearest appropriate habitat. Such
incidents occur regularly in southern California.
Several administrators have suggested to us
that this policy could be modified to favor
translocating such non-problem animals into the
Santa Ana Mountain Range. Although clearly
more artificial and less aesthetically pleasing
than maintaining natural connectivity and
letting cougars immigrate on their own, such an
approach may be feasible. However, it would
clearly be an unprecedented experiment, and
would require a commitment (by CDFG) and
funding (most appropriately from the planning
agencies and developers that cause loss of
existing linkages) in perpetuity. If such an
option is pursued, it should include:
• importing only animals of dispersal age
(12-28 months ofage).
• , importing only animals from a similar
habitat type in southern California.
• monitoring the results. This would be a
large experiment. Transplanted animals
would suffer high mortality, and could
disrupt the social structure or resident
cougars; such impacts would depend on
the existing demographics of the
population. If the translocation option is
chosen, many resident cougars and all
30
transplanted animals should be radiotagged
and monitored. The monitoring
effort should continue for at least 20
years, with annual support similar to that
expended in our study.
Chino Hills State Park to Trabuco Ranger
District
A wildlife corridor for cougars between
the Santa Ana Mountain Range and the Chino
Hills will allow cougars to use an area (the
Chino Hills) that cannot support a population
of cougars if it were to become isolated (Beier
1993). Quite simply, if there is no corridor,
then there will be no cougars in the Chino Hills.
To be effective, such a corridor must' not
simply be a freeway underpass, but must reach
from Trabuco Ranger District and the adjacent
Tecate Cypress Reserve in upper Coal Canyon
(the northernmost protected parcels in the Santa
Ana Mountain Range) to Chino Hills State
Park (the southernmost protected parcel in the
Chino Hills).
We approached our evaluation of
potential movement corridors from the
perspective of a cougar attempting to travel
north from the Santa Ana Mountain Range into
the Chino Hills (Figure 8). State Route 91
(Riverside Freeway) and associated urban
growth form a narrow band separating the
Chino Hills on the north from the Santa Ana
Mountain Range to the south. Cougars can
approach the south side of Highway 91 along
the entire 5.5 km from Gypsum Canyon to the
Green River Road exit. Unlike 1-15 near
Temecula, the Riverside Freeway's 8 lanes are
too busy at night to allow safe at-grade
crossings by wildlife. There were 11 culverts
and 3 vehicle underpasses in this 5.5-km
section. Seven of the culverts were < 3 ft in
width and height and were located such that it
would be nearly impossible for a cougar to find
the entrance. Two others (a 4-ft diameter
cylinder and a 5-ft wide box) were similarly