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RARE and endangered plants and animals
at Lawrence Livermore? Perhaps surprisingly, there are a few at
the heavily developed main site, even as suburban Livermore edges
ever closer. Twenty-four kilometers to the east, nestled in California’s
Coast Range, the Laboratory’s Site 300 is home to many
more. Here, at the Laboratory’s testing range for high explosives,
interesting flora and fauna abound on 28 square kilometers of rolling
grasslands and steep ravines.
At the main Livermore site, California red-legged frogs (Rana
aurora draytonii), a federally listed threatened species, live in a small
creek and are regularly monitored. They are also breeding in a
drainage retention basin on site for the first time now that Laboratory
wildlife biologists have controlled the bullfrog (a nonnative predator) population. The California tiger salamander (Ambystoma californiense),
which may soon be listed as threatened, has been seen near the
Livermore site.
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When a controlled fire burns through
an area at Site 300, it removes most vegetation but leaves
behind patches of unburned ground where big tarplants (Blepharizonia
plumosa) can mature, flower, and provide seed for the following
year.
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“White-tailed kites (Elanus
leucurus), a California fully
protected bird of prey, are successfully fledging their young most
years
at the main site,” says Livermore wildlife biologist Mike
van Hattem. “Typically, we see many of the same birds here
that we see in a suburban environment.” No rare native plants
have been found at the Livermore site.
At
Site 300, golden eagles are a common sight and feral pigs wreak
havoc now and then on the environment. A variety of plants and
animals thrive in the site’s grasslands and vernal pools,
including a species of poppy discovered in the last decade that
was thought to be extinct. Seven other species of rare plants are
also found at Site 300 alongside numerous rare species of bats,
mice, amphibians, snakes, beetles, eagles, hawks, and smaller birds.
Biologist
Thom Kato, group leader for Livermore’s Environmental
Evaluations Group in the Environmental Protection Department, has
overall responsibility for wildlife monitoring and research at
the Laboratory. The wildlife biologists in his group conduct monitoring
programs required by existing permits and pursue efforts to track
the distribution and abundance of rare and endangered species.
The majority of their monitoring and research efforts are directed
at Site 300, so that staff there can plan appropriately for explosives
testing. “Our goal is to be in a position to meet constantly
changing regulations and ensure overall regulatory compliance,” says
Kato. “That requires being fully familiar with all species
at Site 300.”
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The
data are not conclusive, but it appears that populations of
the big tarplant (Blepharizonia plumosa) may come back in greater
numbers two years after being burned, as shown in these Site
300 maps for years (a) 2000, (b) 2001, and (c) 2002. Controlled
burns are conducted in late spring or early summer, and plants
are surveyed in the fall. |
Stalking the Wild Blepharizonia Plumosa
Most of Site 300 is undeveloped, and the area has been closed to
the public since the testing range was established in the mid-1950s.
Biologists cite these factors and the frequency of controlled burns
for the existing botanical diversity at Site 300. Of the eight
rare plants there, restoration or monitoring activities are being
conducted for three of them.
The large-flowered fiddleneck (Amsinckia
grandiflora) exists in
two populations; however, one of these may have been lost as a
result of heavy rains in 1997. Just one other natural population
is known to exist. An active program is under way to maintain these
habitats and establish additional experimental populations because
the overall numbers of the large-flowered fiddleneck are shrinking.
Better
news exists about the diamond-petaled poppy (Eschscholzia rhombipetala).
Experts thought this plant to be extinct, but it was rediscovered
at the Carrizo Plain (California central coast)
in 1992 and then at Site 300 in 1997. Laboratory biologists
discovered a second population in 2002, and the number of plants
in the original Site 300 population appears to be expanding.
The
third rare plant actively monitored is the big tarplant (Blepharizonia
plumosa), which is widespread throughout the site but extremely
rare elsewhere. Monitoring has shown that populations of the big
tarplant were somewhat larger in 2002 than those observed in 2001,
particularly in areas burned in the past but not burned in the
spring of 2002. Because controlled burns are such an integral part
of safety management at Site 300, this apparent correlation with
changing numbers of a rare plant warrants attention.
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(a) A mist net is set up near the
Elk Ravine Bird Banding Station at Site 300. (b) A
female common yellow-throat (Geothlypis trichas) is trapped
in the mist net, then later banded and released unharmed.
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Detailed
monitoring has shown that the big tarplants themselves don’t survive direct contact with the late-spring and early-summer
fires because the fall-blooming plants are still small at this
time. But the burns are patchy, so some plants survive in the unburned
patches and are able to mature, flower, and provide seed for the
following year. The next year’s plants have the advantage
of reduced competition from other plants in the burned area and
often come back in even greater numbers.
Some
areas of Site 300 are burned every year for safety reasons, while
other areas have burn requirements that vary from year to
year. “If there is flexibility with regard to burning, we
could explore the possibility of giving an area a rest when the
big tarplant population is down so that populations can expand
the following year,” says Tina Carlsen, an ecologist. “Conversely,
we could burn the population area and see if the tarplant comes
back in greater numbers.
“Now,
we’re working to establish a statistical correlation
between the controlled burns and populations of the big tarplant.
A challenge is that we must consider many other contributing factors
besides the fire itself, such as the time of the fire, weather
conditions, other plants and animals in the area, and so on. Every
year is slightly different. Ecology is a complicated science.”
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Two male tricolored blackbirds (Agelaius
tricolor) in the wild. A search for the nesting sites of
these birds is ongoing at Site 300.
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For
the Birds
In
2002, the Laboratory began to prepare a new Environmental Impact
Statement (EIS) evaluating the environmental consequences of continuing
operations. An important aspect of the EIS is providing up-to-date
information on sensitive ecological resources at the Laboratory.
As part of gathering this broad array of ecological data, a census
was started of bird species at Livermore. Gathering this information
helps to ensure that mission activities at Site 300 go on as planned
and are not interrupted by regulatory requirements aimed at protecting
declining populations of migratory and other bird species. Because
too little was known about Site 300 bird populations to adequately
prepare the EIS, van Hattem started a program to count resident
and migratory birds. A team of biologists and volunteers has identified
103 species, of which 24 are state or federal species of special
concern and two, the Swainson’s hawk (Buteo swainsoni) and
willow flycatcher (Empidonax traillii), are listed as California-threatened
and endangered species.
The team elected to use an established and well-defined national
protocol known as the Monitoring Avian Productivity and Survivorship
(MAPS) Program. MAPS was created in 1989 by the Institute for Bird
Populations (IBP) of Point Reyes Station, California, to assess
and monitor the vital rates and population dynamics of more than
120 species of North American land birds in order to provide critical
conservation and management information on their populations. Since
its first season, MAPS has grown nationally from 16 to 570 monitoring
stations and has received the support and endorsement of many federal
agencies and conservation groups. Because MAPS is a widely accepted
methodology, the Laboratory is able to defend the information that
it collects and bases its decisions on, and can provide important
information to a much broader national effort.
Birds are captured in mist nets, banded in accordance with a permit
from the Bird Banding Laboratory (BBL) of the U.S. Geological Survey
Biological Resources Division, and released unharmed. Information
on the habitat, sex, and estimated age and health of banded birds
goes to the BBL. Working with biologists all over the country,
the BBL and the IBP have established an unprecedented storehouse
of data on birds available to all citizens and agencies.
“Site 300 is on the Pacific Flyway—one of the four major North
American migratory routes—so we get all kinds of visitors,” says
van Hattem. “We’ve banded a varied thrush (Ixoreus
naevius) found usually in the redwoods and a black-throated sparrow
(Amphispiza bilineata) that belongs near Mono Lake on
the eastern side of the Sierra Nevada.” Van Hattem has also
directed a search of nesting sites for the tricolored blackbird
(Agelaius
tricolor), a federal species of concern whose numbers are declining
throughout its range.
While
continuing to provide important data needed to fulfill environmental
protection requirements, these and other avian monitoring programs
will allow wildlife biologists to identify and describe patterns
of bird populations across time and space, not only at Site 300
but also in broader geographic areas. Researchers can then begin
to identify how these patterns are related to the ecological characteristics
and population trends of various species, their habitat characteristics,
and the ever-unpredictable weather. Working with Site 300 staff,
wildlife biologists can also suggest ways to carry out programmatic
activities while ensuring that site activities have minimal direct
effect on migratory birds and do not result in violations of regulations
protecting some species. Efforts to integrate management actions
and conservation strategies with programmatic activities may even
help to reverse the decline of bird populations and maintain stable
or increasing populations.
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A captured male Luzuli Bunting
(Passerina amoena) about to be released.
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A Safe Haven
“As time goes on, there will be more concern about the health of
our ecosystem,” Kato says. “We have the unusual and
important task of helping to ensure that the Laboratory performs
its primary mission while at the same time contributing to the
conservation, and potentially to the eventual recovery, of endangered
species at Livermore.”
By offering a safe haven for rare flora and fauna, Livermore
is helping some of the rich diversity of our world to survive
and
thrive.
—Katie Walter
Key Words: birds, Blepharizonia plumosa (big tarplant), endangered
species, plants, threatened species, wildlife.
For further information contact Thom Kato (925) 423-9642
(kato3@llnl.gov).
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