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| A storm system moving over the Tehachapi Mountains, viewed from the verdant blooming Antelope Valley, March 2015. |
It seems like the California drought is a hot topic on
everyone’s mind these days, and that’s certainly a good thing. But can we understand more about the severity
of the regional drought here on Tejon Ranch and its effects on biodiversity by looking
closely at weather instrument data to see how much rain falls, or where the
temperature is most extreme? How is the
weather changing over time? How does
precipitation vary across the diverse topography of the Ranch and what effects
does it produce? Good questions, and
we’re just beginning to see some tantalizing patterns.
On the Ranch, the Conservancy monitors seven (soon to be
eight) weather stations spread out across the 270,000 acres that make up the
Ranch. From our lowest elevation sites
in the San Joaquin Valley (500 feet), up to our highest elevation in the
Tehachapi Mountains (6800 feet), and over to our high desert grass and shrublands
of the Antelope Valley in the extreme western Mojave Desert (3000 feet),
there’s an extraordinary diversity of elevation and aspect. For this season’s weather summary, we’re
looking closely at three of the seven stations. Here’s a look at the data for the spring months, plus the total rainfall
from October 2014 through April 2015 at each station.
Comanche Point
San Joaquin Valley, elevation 562 feet
Total Rainfall October 2014-April 2015: 1.11 inches
|
Average temperature (°F)
|
Maximum temperature (°F)
|
Minimum temperature (°F)
|
Precipitation (inches)
|
|
|
February
|
65.4
|
76.7
|
52.9
|
0.00
|
|
March
|
66
|
90.1
|
47.7
|
0.00
|
|
April
|
64.3
|
93.4
|
39.6
|
0.09
|
Michener
Ridgeline of mountains north of Gorman, elevation 4716 feet
Total Rainfall October 2014-April 2015; 5.30”
|
|
Average temperature (°F)
|
Maximum temperature (°F)
|
Minimum temperature (°F)
|
Precipitation (inches)
|
|
February
|
53.7
|
71
|
34.6
|
0.22
|
|
March
|
55.6
|
79
|
34.9
|
0.43
|
|
April
|
53.6
|
80.8
|
33.4
|
0.44
|
Antelope Canyon
Antelope Valley, elevation 3594 feet
Total Rainfall October 2014-April 2015; 6.64”
|
|
Average temperature (°F)
|
Maximum temperature (°F)
|
Minimum temperature (°F)
|
Precipitation (inches)
|
|
February
|
57
|
83.1
|
34.2
|
0.66
|
|
March
|
57.7
|
82
|
31
|
0.80
|
|
April
|
57
|
83.1
|
34.2
|
0.66
|
Notice that the Antelope Canyon weather station reported the
most rain at 6.64 inches, far more than the amount seen on the San Joaquin side
of the Ranch. Docents and professional
staff both noted the spectacular wildflower display in the Antelope Valley. Additionally,
pronghorn seemed exceptionally easy to view this spring in the Antelope Canyon
area, and three new fawns have been observed adjacent to this canyon.
In contrast, Comanche Point actually experienced three
months during October-April with no rain at all. In fact, wildflower viewing on
the San Joaquin side was cancelled for the season due to a sparse display. What
we did see in this area was an astounding density and distribution of exotic
invasive mustard species—Saharan mustard (Brassica
tournefortii), short pod mustard (Hirschfeldia
incana), and hedge mustards (Sisymbrium
spp.). Land managers across the state have been marveling at the banner year
that invasive mustards are having, and Tejon Ranch is no exception. Warm and
dry winters seem to favor these concerning species—something for managers to be
aware of in planning weed treatment efforts in future growing seasons.
We’d love to look at longer trends in the weather data--do
springs flow more in wet seasons or is groundwater unaffected? Is Antelope Canyon a small microenvironment
that tends to see more rain, or was this just a fluke “outlier” year? Are pronghorn always in that area in the
spring, or did they gather there just for this season? Does the weather information we’re gathering
here at the Ranch agree with weather stations from nearby locations? We’ve just started gathering and analyzing the
weather data, and are working to upgrade the actual station instruments. Some weather stations are older than others,
and require a loving touch to maintain. Over
the next few years, we hope to upgrade all of the stations, and perhaps add
more stations in other interesting areas of the Ranch. Still, it’s fascinating to look at this one
snapshot of spring season and see the overt response of precipitation driving biodiversity.
Dr. Richard Chapleau
is a retired science teacher who lives in the Antelope Valley neighboring Tejon
Ranch. He and his wife Lisa Chapleau, a retired math teacher, have been
volunteering with the Conservancy for a year and have inspired Conservancy
staff with their keen smarts, their many talents, and their phenomenal
generosity of time, expertise, and exceptional homegrown eggs. Among other
kind donations of time and energy, they have taken the helm of our weather
program--maintaining weather stations, downloading and organizing data, and analyzing
results. This spring they installed a newly acquired RainWise weather station
at the Conservancy office in Lebec with a live link online for real-time
weather data. Check it out at:
