COMMISSION

Sonoran Desert, desert ironwood (Olneya tesota) provides shade and refuge from extreme
temperatures, thereby modifying the area beneath its canopy to act as a nursery area
for recruitment of new seedlings (Tewksbury and Lloyd 2001). Consequently, due to its
multitude of inherent benefits to other native flora and fauna, the loss of vegetation is likely
to impact the overall health of the desert ecosystem. Therefore, vegetation cover is likely to
act as an indicator of overall habitat health in Ocotillo Wells SVRA due to its essential utility
by other flora and fauna species.
Birds
As of 2014, bird monitoring methodology at Ocotillo Wells SVRA has been revised to
follow the Landbird Monitoring Protocol for the Sonoran Desert Network developed by the
National Park Service (NPS) (Beaupré et al. 2013). This protocol uses point transects, or
a series of six permanent points, randomly placed and spaced at least 250 meters apart
around a plot center point. Observers spend eight minutes at each of the six points and
record all birds seen or heard. Any birds flushed in route to sample points will also be
recorded. The species, number of individuals, distance from the point to the observed birds,
and sex and age (when known) are recorded.
Sampling occurs twice per year, in the winter (December/January) and spring (March/April),
in an attempt to record migratory, resident, and spring breeding birds. Sampling occurs
in the morning, starting as soon as it is light enough to see at least 200 meters and does
not continue past noon (Beaupré et al. 2013). A pilot study for bird protocols was initiated
in 2014, and continued in 2015. Data collected for birds was analyzed in 2015 after two
consecutive years of surveys were completed.
Bats
Bat monitoring was attempted in the fall of 2013 and spring of 2014. Monitoring used a
pole-mounted microphone attached to a Wildlife Acoustics SM2BAT SongMeter system
capable of recording echolocation frequencies. The system was placed near Ocotillo Wells
District office and a light source where bats have been observed feeding in the crepuscular
hours. Difficulty was encountered in distinguishing the call signatures of distinct bat species
detected by the system.
Software that analyzes bat calls to determine species would greatly increase the accuracy
and efficacy of these monitoring efforts. In addition, bat monitoring courses are offered
intermittently by various organizations. Staff attendance at one of these training courses
would also be immensely beneficial for the success of bat monitoring efforts. At a minimum,
additional research is required to continue to attempt further bat monitoring into the future at
Ocotillo Wells SVRA.
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California State Parks, Off-Highway Motor Vehicle Recreation Commission