Southern California's most severe drought on record is beginning to
exact a toll on habitat and wildlife in a region with the greatest
number of endangered species in the continental United States.
While snow and rainfall have been normal in
other parts of the state, including the Sierra Nevada, the southern
half of the state is far drier than usual.
Seasonal streams that normally don't dry up
until midsummer are barren depressions or chains of shallow potholes
choked with algae.
While the drought threatens a number of
water-dependent plants and animals, conservationists are
particularly concerned about the fate of southern steelhead, the
rarest sea-going trout in the United States. State biologist Mary L.
Larson is drafting an emergency plan to rescue the southern
steelhead in San Mateo Creek along the northern border of Camp
Pendleton this summer if the drought persists.
"We can't let these fish die,"
Larson said.
Six months ago, Larson became the first
state Fish & Game Department biologist specifically assigned to
coordinate restoration efforts of steelhead habitat in Southern
California.
"We'd like to have a plan in place for
this summer, so if the worst-case scenario happens, the fish won't
die," she said.
She envisions a rescue plan similar to the
practice at the Carmel River in Monterey County, where the steelhead
and salmon are plucked from the river and taken upstream to deeper
pools.
If upstream pools in San Mateo Creek are
too dry, the rare steelhead could be taken to a state hatchery at
Fillmore in Ventura County until the water level rises, she said.
She must persuade scientists with the
National Marine Fisheries Service to go along with the plan. The
policy of the federal agency, which takes over jurisdiction of the
San Mateo Creek steelhead July 1, is not to intervene when nature
threatens wildlife.
A few hundred southern steelhead are all
that remain in the low-flowing streams between San Luis Obispo
County and San Diego.
The southern steelhead is a type of rainbow
trout that, like salmon, begins life in fresh water before going to
sea. What makes the southern steelhead special is its genes. It is
the oldest in the evolutionary chain of West Coast steelhead, which
range as far north as the U.S.-Canada border.
Last week, Larson concluded a weeklong
assessment of streams and rivers in Southern California.
Accompanied by Allen Greenwood, an amateur
naturalist and expert on San Diego's wild trout, Larson hiked 21
miles and inspected 31 back-country streams.
She observed an ecosystem showing signs of
stress from drought.
"It's August already in the
foothills," she said.
At lower elevations, the few wildflowers
that sprouted this spring have been overrun by non-native rye grass.
San Diego is on track to its lowest-ever
rainfall seasonal total since 1850, when record-keeping began. Since
July 1, 2001, 3.02 inches of rain has fallen. The season ends June
30. The National Weather Service said this past winter was the
driest on record for San Diego and Riverside counties. San Diego
County has 40 plants and animal species listed as either threatened
or endangered, more than any county in the nation.
While most of the plants and animals native
to the chaparral have evolved to withstand drought, biologists are
concerned that some endangered species could be pushed closer to the
edge of extinction.
"We would expect to see reduced
reproduction this year for species that are water-dependent, such as
endangered arroyo toads," said Jane Hendron, spokeswoman for
the U.S. Fish and Wildlife Service in Carlsbad.
Scientists at Pepperdine University
recently documented a decline in egg production among frogs and
newts in the Santa Monica Mountains.
Annual wildflowers and clover that serve as
the host plant for the endangered Quino checkerspot butterfly
sprouted and quickly wilted in the parched San Diego back country.
"In the lower elevations closer to sea
level, everything is pretty crispy," said Meredith Osborne, a
botanist for the state. "The annual plants are really very
sparse this year."
Drought-tolerant sage scrub and chaparral
are in bloom, but relatively few pollinating insects are bouncing
from blossom to blossom.
"You can't belive how bad it is in the
back country," said Greenwood, 60, who has been exploring San
Diego's creeks and rivers since he was a teen.
"Water from the snowpack in the Laguna
Mountains wasn't enough this year to charge the aquifers feeding the
springs that supply the streams," he said. Southern steelhead
were thought to be extinct south of Malibu Creek in Los Angeles
County until they were discovered 100 miles south at San Mateo Creek
in February 1999.
Walking with state biologists after the
discovery, Greenwood counted 46 adult steelhead in the pools in the
lower and middle reaches of the creek.
Scientists aren't sure how many are still
alive. State biologists in January found several steelhead in the
deepest pools in San Mateo Creek and a tributary, Devil's Canyon
Creek, northeast of Camp Pendleton.
The creek originates in Riverside County
from springs in the Santa Ana Mountains. The farthest the steelhead
can go upstream is Tenaja Falls about 20 miles from the Pacific
Ocean.
After hiking to the base of the falls last
week, Greenwood and Larson were disappointed to find the flow had
been reduced to a garden-hose-like trickle.
"The falls here should be raging with
water," said Greenwood. "This is how it normally looks in
late August or September."
Larson said she's got plenty of ideas for
helping the steelhead.
Perhaps water districts can be persuaded to
time their releases of water below dams to help the fish. Maybe
ranchers can cooperate by fixing their ponds so non-native bass and
other fish aren't flushed into the creek during floods. Along the
lower reaches of the creek, where the stream bed is too wide and
shallow, the channel could be deepened and replanted with willows,
sycamores and other native trees to shade the water.
The state Coastal Conservancy has $800,000
earmarked for steelhead restoration at the creek, and Larson is
eager to set up a committee to review grant applications.
"It's going to take 20 years or
more," she said. "We may not see southern steelhead
de-listed (from the endangered species list), but we'll make great
strides."
Terry Rodgers: (619) 542-4566;
terry.rodgers@uniontrib.com
